Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Bihar Board 12th Chemistry Objective Questions and Answers

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 1.
Which of the following is a primary halide ?
(a) iso-Propyl iodide
(b) sec-Butyl iodide
(c) tert-Butyl bromide
(d) neo-Hexyl chloride
Answer:
(a) iso-Propyl iodide

Question 2.
Which of the following is not an allylic halide ?
(a) 4-Bromopent-2-ene
(b) 3-Bromo-2-methylbut-1-ene
(c) 1-Bromobut-2-ene
(d) 4-Bromobut-1-ene
Answer:
(d) 4-Bromobut-1-ene

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 3.
The IUPAC name of tertiary butyl chloride is
(a) 2-chloro-2-methypropane
(b) 3-chlorobutane
(c) 4-chlorobutane
(d) 1, 2-chloro-3-methylporpane
Answer:
(a) 2-chloro-2-methypropane

Question 4.
The IUPAC name of CH3)2 CH – CH2 – CH2Br is
(a) 1-bromopentane
(b) 1-bromo-3-methylbutane
(c) 2-methyl-4-bromobutane
(d) 2-methyl-3-bromopropane
Answer:
(b) 1-bromo-3-methylbutane

Question 5.
The IUPAC name of the compound is
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 1
(a) 1 -fluoro-4-methyl-2-nitrobenzene
(b) 4-fluoro-lmethyl-3-nitrobenzene
(c) 4-methyl-l-fluoro-2-nitrobenzene
(d) 2-fluoro-5-methyl-1 -nitrobenzene
Answer:
(d) 2-fluoro-5-methyl-1 -nitrobenzene

Question 6.
Which of the following compounds can yield only one monochlorinated product upon free radical chlorina­tion ?
(a) 2, 2-Dimethylpropane
(b) 2-Methylpropane
(c) 2-Methylbutance
(d) n-Butane
Answer:
(a) 2, 2-Dimethylpropane

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 7.
Bromination of methane in presence of sunlight is a
(a) nucleophilic substitution
(b) free radical substitution
(c) electrophilic substitution
(d) nucleophilic addition
Answer:
(b) free radical substitution

Question 8.
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 2

Question 9.
The reaction
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 3
(a) nucleophilic addition
(b) free radical addition
(c) electrophilic addition
(d) electrophilic substitution
Answer:

Question 10.
Which of the following reactions follows Markovnikov’s rule ?
(a) C2H4 + HBr
(b) C3H6+Cl2
(c) C3H6+ HBr
(d) C3H6 + Br2
Answer:
(c) C3H6+ HBr

Question 11.
Methyl bromide reacts with AgF to give methyl fluride and silver bromide. This reaction is called
(a) Fitting reaction
(b) Swarts reaction
(c) Wurtz reaction
(d) Finkelstein reaction
Answer:
(b) Swarts reaction

Question 12.
Which of the following molecules has highest dipole moment ?
(a) CH3Cl
(b) CH2Cl2
(c) CHCl2
(d) CCl4
Answer:
(a) CH3Cl

Question 13.
Which of the following compounds has the highest boiling point ?
(a) CH3CH2CH2Cl
(b) CH3CH2CH2CH2Cl
(c) CH3CH(CH3)CH2CH2Cl
(d) (CH3)3CCl
Answer:
(b) CH3CH2CH2CH2Cl

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 14.
Which one of the following is not correct order of boiling point of the alkyl/aryl halides ?
(a) CHCl3 > CH2Cl2
(b) CH3(CH2)3CI>CH3(CH2)2Cl
(c) (CH3)3CCl > (CH3)2CHCH2Cl
(d) CH3(CH2)3Cl >CH3CH2CHClCH3
Answer:
(c) (CH3)3CCl > (CH3)2CHCH2Cl

Question 15.
Which of the following compounds will have highest melthing point ?
(a) Chlorobenzene
(b) o-Dichlorobenzene
(c) m-Dichlorobenzene
(d) p-Dichlorobenzene
Answer:
(d) p-Dichlorobenzene

Question 16.
Choose the correct increasing order of density of the following compound.
(a) C3H7CI < C3H7I < CH2CI2 < CCI4
(b) C3H7I < C3H7CI < CH2CI2 < CCI4
(c) C3H7I < C3H7CI < CCI4 < CH2CI2
(d) CCI4 < CH2CI2 < C3H7I < C3H7CI
Answer:
(a) C3H7CI < C3H7I < CH2CI2 < CCI4

Question 17.
Alkyl halides are immiscible in water though they are polar because
(a) they react with water to give alcohols
(b) they cannot form hydrogen bonds with water
(c) C – X bond cannot be broken easily
(d) they are stable compounds and are not reactive
Answer:
(b) they cannot form hydrogen bonds with water

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 18.
Butane nitrile can be prepared by heating
(a) propyl alcohol with KCN
(b) butyl chloride with KCN
(c) butyl alcohol with KCN
(d) propyl chloride with KCN
Answer:
(b) butyl chloride with KCN

Question 19.
Ethyl alcohol is obtained when ethyl chloride is beild with
(a) alcohoic KOH
(b) aqueous KOH
(c) water
(d) aqueous KMnO4
Answer:
(b) aqueous KOH

Question 20.
Which of the following alkyl halide undergoes hydrolysis with aqueous KOH at the fastest rate ?
(a) CH3CH2CH2CI
(b) CH3CH2CI
(c) CH3CH2CH2CH2CI
(d) CH3CH2CH(Br)CH3
Answer:
(d) CH3CH2CH(Br)CH3

Question 21.
The alkyl halide is converted into an alcohol by
(a) elimination
(b) dehydrohalogenation
(c) addition
(d) substitution
Answer:
(d) substitution

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 22.
An alkyl halide, RX reacts with KCN to give propane nitrile, RX is
(a) C3H7Br
(b) C4H9Br
(c) C2H5Br
(d) C5H11Br
Answer:
(c) C2H5Br

Question 23.
Tertiary alkyl halides are practically inert to substitution by SN2 mechanism because
(a) the carbocation formed is unstable
(b) there is steric hindrance
(c) there is inductive effect
(d) the rate of reaction is faster in SN2 mechanism
Answer:
(b) there is steric hindrance

Question 24.
Among the choices of alkyl bromide, the least reactive bromide in SN2 reaction is
(a) 1- bromopentane
(b) 2 – bromo -2- methylbutane
(c) 1 – bromo -3- methylbutane
(d) 1 – bromo -2- methylbutane
Answer:
(b) 2 – bromo -2- methylbutane

Question 25.
Which of the following haloalkanes is most reactive ?
(a) 1-Chloropropane
(b) 1-Bromopropane
(c) 2-Chloropropane
(d) 2-Bromopropane
Answer:
(d) 2-Bromopropane

Question 26.
Consider the following bromides :
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 4
The correct order of SNi reactivity is
(a) A > B > C
(b) B > C > A
(c) B > A > C
(d) C > B > A
Answer:
(b) B > C > A

Question 27.
Consider the following reaction :
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 5
The reaction proceeds with 98% recemisation. The reaction may follow
(a) SN1 mechanism
(b) SN2 mechanism
(c) E1 mechanism
(d) E2 mechanism
Answer:
(a) SN1 mechanism

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 28.
Which one of the following chlorohydrocarbons readily undergoes solvolysis ?
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 6
Answer:
(c)

Question 29.
Which of the following is the most reactive towards nucleophilic substitution reaction ?
(a) ClCH2 — CH = CH2
(b) CH2 = CH — Cl
(c) CH3CH = CH — Cl
(d) C6H5CI
Answer:
(a) ClCH2 — CH = CH2

Question 30.
SN1 reaction is fastest in
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 7
Answer:
(c)

Question 31.
Which of the following alkyl halides is hydrolysed by SN1 mechanism ?
(a) CH3Cl
(b) CH3CH2Cl
(c) CH3CH2CH2Cl
(d) (CH3)3CCI
Answer:
(d) (CH3)3CCI

Question 32.
Which of the following will give enantiomeric pair on reaction with water due to presence of asymmetric carbon atom ?
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 8
Answer:
(c)

Question 33.
Which of the following is most reactive towards aqueous NaOH?
(a) C6H5Cl
(b) C6H5CH2Cl
(c) C6H5Br
(d) BrC6H4Br
Answer:
(b) C6H5CH2Cl

Question 34.
Which of the following haloalkanes reacts with aqueous KOH most easily ?
(a) 1-Bromobutane
(b) 2-Bromobutane
(c) 2-Bromo-2-mthylpropane
(d) 2-Chlorobutane
Answer:
(c) 2-Bromo-2-mthylpropane

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 35.
Which alkyl halide exhibits complete recemisation in SN1 reaction ?
(a) (CH3)3CCl
(b) CH3CH2CH2Cl
(c) CH3CH2Cl
(d) C6H5CH2Cl
Answer:
(d) C6H5CH2Cl

Question 36.
The order of reactivity of various alkyl halides towards nucleophilic substitution follows the order
(a) R – I>R – Br>R – Cl>R – F
(b) R – F>R – Cl>R – Br>R – I
(c) R – Cl>R – Br>R – I>R – F
(d) R – Br>R – I>R- Cl>R – F
Answer:
(a) R – I>R – Br>R – Cl>R – F

Question 37.
2-Bromo-3,3-dimethyIbutance on reaction with aqueous KOH yields X as the major product. X is
(a) 2, 3, 3-trimethylpropan-1-ol
(b) 2, 2-dimethylbutan-3-ol
(c) 2, 3-dimethylbutan-2-ol
(d) 2,2-dimethylpropan-2-ol
Answer:
(c) 2, 3-dimethylbutan-2-ol

Question 38.
Ethylene dichloride and ethylidene chloride are isomeric compounds. The false statement about these isomers is that they ………………..
(a) are both hydrolysed to the same product
(b) contain the same percentage of chlorine
(c) are position isomers
(d) react with alcoholic potash and give the same product
Answer:
(a) are both hydrolysed to the same product

Question 39.
The major product formed in the following reaction is
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 9
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 10
Answer:
(d)

Question 40.
A mixture of 1-chloropropane and 2-chloropropane when treated with alcoholic KOH gives
(a) prop-1 -ene
(b)  prop-2-ene
(c) a mixture of prop-1-ene and prop-2-ene
(d) propanol
Answer:
(a) prop-1 -ene

Question 41.
2-Chloro-2-methylpropane on reaction with ale. KOH gives X as the product. X is
(a) but-2-ene
(b)  2-methylbut-1-ene
(c) 2-methylprop-1-ene
(d) 2-methylbutaion-2-ol
Answer:
(c) 2-methylprop-1-ene

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 42.
Reaction of trans-2-phenyl-l-bromocyclopentane on reaction with alcoholic KOH produces
(a) 4-phenylcyclopentene
(b) 2-phenylcylopentene
(c) 1-phenylcyclopenetene
(d) 3-phenylcyclopentene
Answer:
(d) 3-phenylcyclopentene

Question 43.
Identify (Z) in the following reaction series.
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 11
Answer:
(b)

Question 44.
The ease of dehydrohalogenation of alkyl halide with alcoholic KOH is
(a)3°<2°< 1°
(b) 3°>2°> 1°
(c) 3°<2°> 1°
(d) 3°>2°< 1°
Answer:
(b) 3°>2°> 1°

Question 45.
Elimination of bromine from 2-bromobutane results in the formation of
(a) equimolar mixture of 1 and 2-butene
(b) predominantly 2-butene
(c) predominantly 1-butene
(d) predominantly 2-butyne
Answer:
(b) predominantly 2-butene

Question 46.
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 12
In the given reaction what will be the final product ?
(a) CH3CH2CH2I
(b) CH3CHICH2I
(c) CH3CH2CH2CH2CH3
(d) CH3CH2CHI2
Answer:
(a) CH3CH2CH2I

Question 47.
The order of reactivites of methyl halides in the formation of Grignard reagent is
(a) CH3I>CH3Br>CH3CI
(b) CH3CI > CH3Br > CH3I
(c) CH3Br>CH3CI>CH3I
(d) CH3Br > CH3I > CH 3CI
Answer:
(a) CH3I>CH3Br>CH3CI

Question 48.
Alkyl halides react with metallic sodium in dry ether producing
(a) alkanes with same number of carbon atoms
(b) alkanes with double the number of carbon atoms
(c) alkenes with triple the number of carbon atoms
(d) alkenes with same number of carbon atoms
Answer:
(b) alkanes with double the number of carbon atoms

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 49.
On treating a mixture of two alkyl halides with sodium metal in dry ether, 2-methylpropane was obtained. The alkyl halides are
(a) 2-chloropropana and choromethane
(b) 2-chloropropane and chloroethane
(c) chloromethane and chloroethane
(d) chloromethane and 1-chloropropane
Answer:
(a) 2-chloropropana and choromethane

Question 50.
Chlorobenzene on treatment with sodium in dry ether gives diphenyl. The name of the reaction is
(a) Fitting reaction
(b) Wurtz-Fitting reaction
(c) Sandmeyer reaction
(d) Gattermann reaction
Answer:
(a) Fitting reaction

Question 51.
Aryl halides are less reactive towards nucleophilic substitution reactions as compared to alkyl halides due to
(a) formation of a less stable carbonium ion in aryl halides
(b) resonance stabilisation in aryl halides
(c) presence of double bonds in alkyl halides
(d) inductive effect in aryl halides
Answer:
(b) resonance stabilisation in aryl halides

Question 52.
The end product (Q) in the following sequence of reactions is
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 13
Answer:
(c)

Question 53.
Chloroform is kept in dark coloured bottles because
(a) it reacts with clear glass
(b) it undergoes chlorination in transparent glass bottles
(c) it is oxidised to poisonous gas, phosgene in sunlight
(d) it starts burning when exposed to sunlight
Answer:
(c) it is oxidised to poisonous gas, phosgene in sunlight

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 54.
Triiodomethane has antiseptic property because of
(a) liberation of iodoform
(b) liberation of free iodine
(c) formation of phosgene gas
(d) none of these
Answer:
(b) liberation of free iodine

Question 55.
The fire extinguisher ‘pyrene’ contains
(a) Carbon dioxide
(b) Carbon disulphide
(c) Carbon tetrachloride
(d) Chloroform
Answer:
(c) Carbon tetrachloride

Question 56.
An organic halogen compound which is used as refrigerant in refrigerators and air conditioners is (a)BHC
(b) CCl4
(c) freon
(d) CHCl3
Answer:
(c) freon

Question 57.
Which one is correct ?
(a) Freon-14 is CF4, Freon-13 is CF3Cl, Freon-13 is CF2Cl2 and Freon-11 is CFCl3
(b) Freons are chlorofluorocarbons
(c) Freons are used as refrigerants
(d) All the above
Answer:
(d) All the above

Question 58.
Toluene reacts with a halogen in the presence of iron (III) chloride giving ortho and para halo compounds. The reaction is
(a) electrophilic elimination reaction
(b) electrophilic substitution reaction
(c) free radical addition reaction
(d) nucleophilic substitution reaction
Answer:
(b) electrophilic substitution reaction

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 59.
Which reagent will you use for the following reaction ?
CH3CH 2CH2CH3 → CH3CH 2CH2CH2CI + CH3CH2CHCICH3
(a) Cl2/UV light
(b) NaCl + H2SO4
(c) Cl2 gas in dark
(d) Cl2 gas in the presence of iron in dark
Answer:
(a) Cl2/UV light

Question 60.
Which of the following is an example of vic-dihalide ?
(a) Dichloromethane
(b) 1, 2-Dichloroethane
(c) Ethylidene chloride
(d) Allyl chloride
Answer:
(b) 1, 2-Dichloroethane

Question 61.
The position of – Br in the compound in CH3CH = CHC(Br) (CH3)2 can be classified as………………….
(a) allyl
(b) aryl
(c) vinyl
(d) secondary
Answer:
(a) allyl

Question 62.
Ethylidene chloride is a/an……………
(a) vic-dihalide
(b) gem-dihalide
(c) allylic halide
(d) vinylic halide
Answer:
(b) gem-dihalide

Question 63.
A primary alkyl halide would prefer to undergo……………..
(a) SN1 reaction
(b) SN2 reaction
(c) a-elimination
(d) racemisation
Answer:
(b) SN2 reaction

Question 64.
Which of the following alkyl halides will undergo SN1 reaction most readily ?
(a) (CH3)3C – F
(b) (CH3)3 C- Cl
(c) (CH3)3 C – Br
(d) (CH3)3 C – I
Answer:
(d) (CH3)3 C – I

Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes

Question 65.
Which is the correct IUPAC name for
Bihar Board 12th Chemistry Objective Answers Chapter 10 Haloalkanes and Haloarenes 14
(a) 1- Bromo-2-ethylpropane
(b) 1 – Bromo-2-ethyl-2-methylethane
(c) 1- Bromo-2-methylbutane
(d) 2-Methyl- 1-bromobutane
Answer:
(c) 1- Bromo-2-methylbutane

Question 66.
hat should be the correct IUPAC name for diethylbromomethane ?
(a) 1-Bromo-1, 1-diethylmethane
(b) 3-Bromopentane
(c) 1-Bromo-1-ethylpropane
(d) 1-Bromopentane
Answer:
(b) 3-Bromopentane

Question 67.
The reaction of toluene with chlorine in the presence of iron and in the absence of light yields …………….

Answer:
(d)

Question 68.
Molecules whose mirror image is non superimposable over them are known as chiral. Which of the following molecules is chiral in nature ?
(a) 2-Bromobutane
(b) 1-Bromobutane
(c) 2-Bromopropane
(d) 2-Bromopropan-2-ol
Answer:
(a) 2-Bromobutane

Question 69.
Which is the corret inreasing order of boiling points of the following compounds ?
1-Bromoethane, 1-Bromopropane, 1-Bromobutane, Bromobenzene
(a) Bromobenzene < 1 -Bromobutane < 1 -Bromopropane
< 1-Bromothane
(b) Bromobenzene < 1-Bromothane < 1-Bromopropane
< 1-Bromobutane
(c) 1-Bromopropane < 1-Bromobutane < 1-Bromothane
< Bromobenzene
(d) 1 -Bromoethane < 1 -Bromopropane < 1-Bromobutane
< Bromobenzene
Answer:
(d) 1 -Bromoethane < 1 -Bromopropane < 1-Bromobutane
< Bromobenzene

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

Bihar Board 12th Hindi Model Papers

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

समय 3 घंटे 15 मिनट
पूर्णांक 100

परिक्षार्थियों के लिए निर्देश

  1. परीक्षार्थी यथा संभव अपने शब्दों में ही उत्तर दें।
  2. दाहिनी ओर हाशिये पर दिये हुए अंक पूर्णांक निर्दिष्ट करते हैं।
  3. इस प्रश्न पत्र को पढ़ने के लिए 15 मिनट का अतिरिक्त समय दिया गया है।
  4. यह प्रश्न पत्र दो खण्डों में है, खण्ड-अ एवं खण्ड-ब।
  5. खण्ड-अ में 50 वस्तुनिष्ठ प्रश्न हैं, सभी प्रश्न अनिवार्य हैं। (प्रत्येक के लिए । अंक निर्धारित है) इनके उत्तर उपलब्ध कराये गये OMR शीट में दिये गये वृत्त को काले/नीले बॉल पेन से भरें। किसी भी प्रकार का व्हाइटनर/तरल पदार्थ/ब्लेड/नाखून आदि का उत्तर पत्रिका
  6. में प्रयोग करना मना है, अथवा परीक्षा परिणाम अमान्य होगा।
  7. खण्ड-ब में कुल 15 विषयनिष्ठ प्रश्न हैं। प्रत्येक प्रश्न के समक्ष अंक निर्धारित हैं।
  8. किसी तरह के इलेक्ट्रॉनिक यंत्र का उपयोग वर्जित है।

खण्ड-अ

वस्तुनिष्ठ प्रश्न

प्रश्न संख्या 1 से 50 तक वस्तुनिष्ठ प्रश्न है जिसके साथ चा विकल्प दिए गए हैं, जिनमें से एक सही है । अपने द्वारा चुने गए सह विकल्प को OMR शीट पर चिह्नित करें। (50 x 1 = 50)

बहुविकल्पिक उत्तरों में से सही उत्तर दें।

प्रश्न 1.
‘बातचीत’ शीर्षक के चरनाकार हैं :
(a) जगदीश चन्द्र माथुर
(b) बालकृष्ण भट्ट
(c) रामचन्द्र शुक्ल
(d) शमशेर बहादुर सिंह
उत्तर:
(b) बालकृष्ण भट्ट

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

प्रश्न 2.
“उषा’ शीर्षक कविता के रचयिता है:
(a) सुभद्रा कुमारी चौहान
(b) ज्ञानेन्द्रपति
(c) जयशंकर प्रसाद
(d) शमशेर बहादुर सिंह
उत्तर:
(d) शमशेर बहादुर सिंह

प्रश्न 3.
‘अर्द्धनारीश्वर’ शीर्षक के रचनाकार हैं :
(a) रामचन्द्र शुक्ल
(b) जगदीश चन्द्र माथुर
(c) हजारी प्रसाद द्विवेदी
(d) रामधारी सिंह ‘दिनकर’
उत्तर:
(d) रामधारी सिंह ‘दिनकर’

प्रश्न 4.
‘प्रेम के पीर’ के कवि कौन हैं :
(a) जायसी
(b) नाभादास
(c) जयशंकर प्रसाद
(d) सुभद्रा कुमार चौहान
उत्तर:
(a) जायसी

प्रश्न 5.
‘रोज’ शीर्षक कहानी के लेखक कौन हैं :
(a) अज्ञेय
(b) मलयज
(c) रामधारी सिंह ‘दिनकर’
(d) नामवर सिंह
उत्तर:
(a) अज्ञेय

प्रश्न 6.
इनमें से कौन-सी रचना प्रसाद जी की नहीं हैं :
(a) देवदासी
(b) कामायनी
(c) झरना
(d) आँसू
उत्तर:
(c) झरना

प्रश्न 7.
पं0 चन्द्रधर शर्मा ‘गुलेरी’ की कहानी का नाम है :
(a) तिरिछ
(b) जूठन
(c) उसने कहा था
(d) इनमें से कोई नहीं
उत्तर:
(c) उसने कहा था

प्रश्न 8.
श्री कृष्ण ने किस पर आक्रमण किया था ?
(a) रावण पर
(b) कंस पर
(c) सहस्रबाहु पर
(d) इनमें से किसी पर नहीं
उत्तर:
(b) कंस पर

प्रश्न 9.
निम्नांकित में से कौन-से रचनाकार बिहार के हैं ?
(a) शमशेर बहादुर सिंह
(b) रामधारी सिंह दिनकर
(c) मोहन राकेश
(d) जगदीश चन्द्र माथुर .
उत्तर:
(b) रामधारी सिंह दिनकर

प्रश्न 10.
तुलसीदास अपना पेट कैसे भरते थे ?
(a) कविताएँ करके
(b) कथावाचन से
(c) रामकथा गाकर
(d) राम श्री राम का नाम लेकर
उत्तर:
(d) राम श्री राम का नाम लेकर

प्रश्न 11.
‘शिक्षा’ शीर्षक निबंध के निबंधाकार कौन हैं ?
(a) जे० कृष्णमूर्ति
(b) उदय प्रकाश
(c) मलयज
(d) मोहन राकेश
उत्तर:
(a) जे० कृष्णमूर्ति

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

प्रश्न 12.
‘गाँव का घर’ कविता के कवित हैं :
(a) ज्ञानेन्द्रपति
(b) जयशंकर प्रसाद
(c) रघुवीर सहाय
(d) इनमें से कोई नहीं
उत्तर:
(a) ज्ञानेन्द्रपति

प्रश्न 13.
ओ सदानीरा’ शीर्षक में किस महापुरुष की चर्चा है ?
(a) बाल गंगाधर तिलक
(b) महात्मा गांधी
(c) सदन मोहन मालवीय
(d) चन्द्रशेखर आजाद’
उत्तर:
(b) महात्मा गांधी

प्रश्न 14.
‘भगवान श्री कृष्ण’ किस कवि के पूज्य थे ?
(a) सूरदास
(b) तुलसीदास
(c) नाभादास
(d) कबीरदास
उत्तर:
(a) सूरदास

प्रश्न 15.
‘जूठन’ शीर्षक की विद्या क्या है?
(a) कहानी
(b) शब्द-चित्र
(c) आत्मकथा
(d) इनमें से कोई नहीं
उत्तर:
(a) कहानी

प्रश्न 16.
‘जयशंकर प्रसाद’ की श्रेष्ठ कृति है :
(a) कामायनी
(b) लहर
(c) आँसू
(d) चित्राधार
उत्तर:
(a) कामायनी

प्रश्न 17.
निम्नांकित में कौन अज्ञेय का उपन्यास नहीं है :
(a) अपने-अपने अजनबी
(b) नदी के द्वीप
(c) शेखर : एक जीवन
(d) त्रिवेणी
उत्तर:
(d) त्रिवेणी

प्रश्न 18.
‘मुक्तिबोध’ का जन्म हुआ था :
(a) रामगढ़ में
(b) भोपाल में
(c) श्योपुर में
(d) वाराणसी में
उत्तर:
(c) श्योपुर में

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

प्रश्न 19.
‘मालती’ किस शीर्षक की पात्रा है ?
(a) रोज की
(b) जूठन की
(c) ओ सदानीरा की
(d) तिरिछ की
उत्तर:
(a) रोज की

प्रश्न 20.
सुभद्रा कुमारी चौहान की मृत्यु का कारण था :
(a) महामारी
(b) कार दुर्घटना
(c) फाँसी
(d) गोली
उत्तर:
(b) कार दुर्घटना

प्रश्न 21.
‘रजनीश’ का संधि-विच्छेद है :
(a) रज + नीश
(b) रजनी + ईश
(c) रजणी + इश
(d) राज + ईश
उत्तर:
(b) रजनी + ईश

प्रश्न 22.
‘पावन’ का सन्धि-विच्छेद है :
(a) पा + वन
(b) पो + अन
(c) पौ + अन
(d) इनमें से कोई नहीं
उत्तर:
(c) पौ + अन

प्रश्न 23.
‘सत्कार’ का संधि-विच्छेद है :
(a) सत + कार
(b) सत् + कार
(c) सम् + कार
(d) स + आकार
उत्तर:
(b) सत् + कार

प्रश्न 24.
“विद्यालय का संधि-विच्छेद है :
(a) विद्या + आलय
(b) विद्या + लय
(c) विद्या + अलय
(d) इनमें से कोई नहीं
उत्तर:
(a) विद्या + आलय

प्रश्न 25.
‘दिनेश’ का संधि विच्छेद है :
(a) दिन + ईश
(b) दिन + इश
(c) दिन + नेश
(d) दीन + ईश
उत्तर:
(a) दिन + ईश

प्रश्न 26.
‘आगमन’ में कौन-सा उपसर्ग है?
(a) अ
(b) आ
(c) आग्
(d) इनमें से कोई नहीं
उत्तर:
(b) आ

प्रश्न 27.
‘पूर्णिमा’ के कौन-सा प्रत्यय है ?
(a) इमा
(b) ईमा
(c) एमा
(d) इनमें से कोई नहीं
उत्तर:
(a) इमा

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

प्रश्न 28.
‘जलज’ कौन-सा समास है ?
(a) तत्पुरुष
(b) अव्ययीभाव
(c) कर्मधारय
(d)द्वन्द्व
उत्तर:
(a) तत्पुरुष

प्रश्न 29.
‘देवालय’ कौन-सा समास है ?
(a) कर्मधारय
(b) अव्ययीभाव
(c) तत्पुरुष
(d) इनमें से कोई नहीं
उत्तर:
(c) तत्पुरुष

प्रश्न 30.
‘लम्बोदर’ कौन-सा समास है ?
(a) बहुव्रीहि
(b) तत्पुरुष
(c) कर्मधारय
(d) द्वन्द्व
उत्तर:
(a) बहुव्रीहि

प्रश्न 31.
‘रात-दिन’ कौन-सा समास है :
(a) द्विगु
(b) बहुव्रीहि
(c) द्वन्द्व
(d) इनमें से कोई नहीं
उत्तर:
(c) द्वन्द्व

प्रश्न 32.
‘प्रतिदिन’ कौन-सा समास है :
(a) अव्ययीभाव
(b) बहुव्रीहि
(c) द्वन्द्व
(d) इनमें से कोई नहीं
उत्तर:
(a) अव्ययीभाव

प्रश्न 33.
‘आग’ का पर्यायवाची शब्द है :
(a) व्योम
(b) पयोज
(c) अग्नि
(d) पीयूष
उत्तर:
(c) अग्नि

प्रश्न 34.
‘ईश्वर’ का पर्यायवाची शब्द है :
(a) आत्मा
(b) परमात्मा
(c) देवेन्द्र
(d) शंकर
उत्तर:
(b) परमात्मा

प्रश्न 35.
‘अन्धकार’ का विलोम है :
(a) प्रकाश
(b) दिन
(c) उजला
(d) सूर्य
उत्तर:
(a) प्रकाश

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

प्रश्न 36.
‘अदेह’ का विलोम है :
(a) विदेह
(b) सुदेह
(c) सदेह
(d) इनमें से कोई नहीं
उत्तर:
(c) सदेह

प्रश्न 37.
‘गोरा’ का विलोम है :
(a) गौर
(b) काला
(c) कुरूप
(d) श्यामला
उत्तर:
(b) काला

प्रश्न 38.
‘ठण्ढ़ा’ का विलोम है :
(a) अग्नि
(b) गर्म
(c) वाष्प
(d) चिनगारी
उत्तर:
(b) गर्म

प्रश्न 39.
“दिवाकार’ का विलोम है :
(a) निशाकर
(b) निशाचर
(c) रजनी
(d) तमस
उत्तर:
(a) निशाकर

प्रश्न 40.
‘साधारण’ का विपरीतार्थक शब्द है :
(a) असामान्य
(b) असाधारण
(c) अस्वाभाविक
(d) इनमें से कोई नहीं
उत्तर:
(b) असाधारण

प्रश्न 41.
‘जिसका आचरण अच्छा है’ के लिए एक शब्द है :
(a) दुराचारी
(b) सदाचारी
(c) सबल
(d) बलवान
उत्तर:
(b) सदाचारी

प्रश्न 42.
‘जिसके पास धन हो’ के लिए एक शब्द है :
(a) निर्धन
(b) निर्दयी
(c) कठोर
(d) जिज्ञासु
उत्तर:
(a) निर्धन

प्रश्न 43.
‘घोड़ा बेचकर सोना’ मुहावरा का अर्थ है :
(a) गहरी नींद में सोना
(b) निश्चिंत होना
(c) अधिक मुनाफा. कमाना ।
(d) व्यापार करना
उत्तर:
(b) निश्चिंत होना

प्रश्न 44.
‘चैन की बंशी बजाना’ मुहावरा का अर्थ है :
(a) मनोरंजन करना
(b) सुखी रहना
(c) समृद्ध होना
(d) आराम से रहना
उत्तर:
(b) सुखी रहना

प्रश्न 45.
‘राई का पहाड़ बनाना’ मुहावरा का अर्थ है :
(a) चुगली करना
(b) छोटी बात को बढ़ा चढ़ा कर कहना
(c) असंभव को संभव करना
(d) इनमें से कोई नहीं
उत्तर:
(b) छोटी बात को बढ़ा चढ़ा कर कहना

प्रश्न 46.
‘हाथ पाँव मारना’ मुहावरा का अर्थ है:
(a) प्रयास करना
(b) नदी में तैरना
(c) पिटाई करना
(d) इशारा करना
उत्तर:
(a) प्रयास करना

प्रश्न 47.
‘हवा में बातें करना’ महावरे का अर्थ है:
(a) धीरे चलना
(b) तेज दौड़ता
(c) बहुत तरक्की करना ।
(d) इनमें से कोई नहीं
उत्तर:
(c) बहुत तरक्की करना ।

प्रश्न 48.
‘धर्म’ का विशेषण है:
(a) धार्मिक
(b) धर्मज्ञ
(c) धर्मा
(d) इनमें से कोई नहीं
उत्तर:
(a) धार्मिक

प्रश्न 49.
‘राष्ट्र’ का विशेषण है :
(a) राष्ट्रीयता
(b) राष्ट्रीय
(c) राष्ट्रवाद
(d) राष्ट्रसंघ
उत्तर:
(b) राष्ट्रीय

प्रश्न 50.
‘चरित्र’ का विशेषण है :
(a) चारित्रिक
(b) चरित्रवान
(c) सुचरित्र
(d) इनमें से कोई नहीं
उत्तर:
(a) चारित्रिक

खण्ड-ब

विषयनिष्ठ प्रश्न

प्रश्न 1.
किसी एक पर निबंध लिखें (1 x 8 = 8)
विद्यार्थी जीवन में खेल कूद, होली, दहेज प्रथा, सामाजिक अभिशाप, आधुनिक भारतीय नारी, विज्ञान का चमत्कार।
उत्तर:
(क) विद्यार्थी जीवन और खेलकूद :
खेलों का जीवन में उतना ही महत्त्वपूर्ण स्थान है जितना अन्न, विद्या अथवा मनोरंजन का । प्राचीनकाल में खेलों की विविध प्रतियोगिताएँ, होती थीं। धीरे-धीरे प्रतियोगिताएँ जिला स्तर से प्रदेश और फिर प्रदेश से देश अथवा राष्ट्र-स्तर पर आ पहुँची। आज यह स्थिति है कि क्रिकेट, हॉकी, मुक्केबाजी, तीर-अंदाजी, बास्केटबॉल, फुटबॉल, मल्ल-युद्ध आदि का विश्व-खेलों में ऊँचा स्थान है। विश्व-खेलों के माध्यम से विश्व-भर के खिलाड़ी एक स्थान पर इकट्ठे होते हैं। विश्व-खेलों का आयोजन विश्व-एकता की दृष्टि से महत्त्वपूर्ण है । खेल मैत्री-भावना को बढ़ावा देते हैं । खेलों के आयोजन प्रतिभा के विकास में सहायक होते हैं । जीवन की नीरसता खेलों से टूटती है। प्रतिभाशाली खिलाड़ियों को आगे बढ़ने का मौका मिलता है। खेलों को जीवन में महत्त्व देते समय नैतिक आचरण करने की आदत डालनी चाहिए । जीवन में खेलों को महत्त्वपूर्ण स्थान न देने का मुख्य कारण खेलों के विषय में उचित प्रशिक्षण न देना है। योग्य खेल-विशेषज्ञों के सान्निध्य में खिलाडियों की प्रतिभा में निखार वैज्ञानिक परिवेश में होता है।

खेलों से हमारा शरीर हृष्ट-पुष्ट तथा सुगठित बनता है। आज के भोले-भाले बालकों को कल के भारत का महान युवा बनना है। इसीलिए स्वामी विवेकानंद ने कहा था, “मेरे बच्चो ! तुम्हें गीता नहीं, फुटबॉल चाहिए । मैं चाहता हूँ कि तुम्हारी मांसपेशियाँ लोहे की हों, नसें फौलाद की हों और मस्तिष्क उसी पदार्थ का बना हो, जिससे कि आकाश में कौंधने वाली बिजली बनी होती है।’
खेलों से हमारा भरपूर मनोरंजन होता है, हमारी कार्यक्षमता बढ़ती है। यदि मनुष्य नियमपूर्वक बराबर खेलता रहे तो वह आजीवन युक्त बना रहता है। खेलों से हममें सहनशीलता, संवेदनशीलता, संगठन, सहयोग, विश्वास, साहस, अनुशासन तथा आज्ञाकारिता की भावना जगती है।

आज का युग भौतिक युग है। आज के मशीनी युग में खेलों का महत्त्व और भी बढ़ जाता है। अच्छा स्वास्थ्य अच्छे मन का भी सूचक है-‘अच्छे तन अच्छा मन’ इसीलिए तो कहा गया है। खेलों को जीवन के
लिए वरदान कहा जा सकता है। स्पष्ट है कि स्वस्थ तन के अभाव में स्वस्थ मस्तिष्क का बनना संभव नहीं है। शरीर को ऐसा बनाने में खेलों का अपना महत्त्व है। खेल जीवन को सार्थक तथा रोचक बनाते हैं।

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

(ख) होती अथवा मेरा प्रिय त्योहार :
होली मेरा प्रिय त्योहार है। यह अपनी झोली में रंग और गुलाल लेकर आती है। यह उल्लास, आनंद और मस्ती का त्योहार है। होली चैत मास के कृष्णपक्ष की प्रतिपदा को मनाई जाती है । इसके एक दिन पहले (प्राय:) होलिकादहन होता है। होलिकादहन की पीछे होलिका (हिरण्यकश्यपु की बहन) हिरण्यकश्यपु और उसके विष्णुभक्त पुत्र प्रह्लाद की जो पौराणिक कथा है, वह सर्वविदित है। समाजशास्त्रियों को कथन है कि कृषि-प्रधान देश भारत के सारे पर्व फसल के साथ जुड़े हुए हैं। होली रबी फसल की आशा (की शुखी) में मनाई जाती है। अगजा’ के दिन ‘संवत’ में लोग गेहूँ की कच्ची बालियाँ भूनकर खाते हैं । ‘होली’ का अर्थ दुग्धपूर्ण अनाज का भूना हुआ रूप होता है। अगजा’ (होलिकादहन) के लिए गाँवों और शहरों में निश्चित स्थान पर होलिकादहन होता है। निश्चित समय पर लोग एकत्र होते हैं। बच्चों द्वारा एकत्र किए गए लकड़ी-गोयठे और घास-पात में आग लगाई जाती है। आग लगते ही लोग ढोल पर थाप दे-देकर होली गाने लगते हैं। अजीब आनंद का वातावरण छा जाता है। वहाँ हँसी-ठिठोली भी खूब होती है। कभी-कभी बच्चे और युवक अतिरिक्त उत्साह में किसी की चौकी या झोपड़ी ही ‘आगजा’ में डाल देते हैं। यह अशोभनीय है। इससे रंग में भंग होता है।

दूसरे दिन खूब धूमधाम से होली शुरू होती है। रंग, गुलाल, नए वस्त्र और रंग-अबीर से रंगे-पुते मुस्कुराते-हँसते चेहरे-यही है इस पर्व की पहचान । घर-घर तरह-तरह के पकवान पकते हैं। सभी एक-दूसरे से आनंदविह्वल होकर मिलते हैं। इस दिन कोई किसी का शत्रु नहीं होता । भाँग और शराब पीकर तथा लोगों पर रोड़े-भरी कीचड़ फेंककर इस त्योहार का मजा किरकिरा नहीं करना चाहिए । जीवन में रस का संचार करनेवाली होली का अभिनंदन तभी सार्थक होगा जब हम संप्रदाय, जाति, धर्म तथा ऊँच-नीच की भावना और विद्वेष से ऊपर उठकर सबको गले लगाने के लिए तैयार होंगे।

(ग) दहेज-प्रथा ….. सामाजिक अभिशाप :
विवाह के समय कन्या के माता-पिता वर पक्ष को जो वस्राभूषण, धन तथा समान देते हैं, उसे दहेज कहते हैं। प्राचीनकाल में इसे ‘यौतक’ या ‘स्रीधन’ कहा जाता था। ‘मनुस्मृति’ में कहा गया है, “मातुस्तु यौतक यत् स्यात् कुमारी भाग एवं सः।” प्राचीनकाल में ‘यौतक’ (दहेज) देने की प्रथा तो थी, पर उसमें किसी प्रकार का दबाव नहीं था। ऐसा नहीं था कि वरपक्ष के लोग कन्यापक्ष के लोगों से जबरदस्ती धन लेते हों। यह पूर्णत: कन्यापक्ष की समार्थ्य और श्रद्धा पर आधृत था।

पर, समय के साथ ही सारी स्वस्थ परंपराएँ लुप्त होती गयीं और उनके स्थान पर रूढ़ियों ने अपना अधिकार जमा लिया। कन्या के विवाह के अवसर पर श्रद्धा से दी जानेवाली राशि अब अनिवार्यता हो गई यहीं से प्रारंभ होता है दहेज का क्रूर नाटक जिसने आज सम्पूर्ण भारतीय समाज को अपने खूनी पंजों के आघात से लहूलुहान कर दिया है। धन के अभाव में पिता अपनी पुत्रियों का विवाह योग्य वर से नहीं कर पाता । वह किसी तरह अपना कर्तव्य पूरा करना चाहता है। किशोरी कन्याओं का विवाह अधेड़ या कभी-कभी उनके पिता की उम्र के पुरुषों से कर दिया जाता है। आज भारतीय समाज में दहेज के कारण ही अविवाहित कन्याओं की संख्या दिन-प्रतिदिन बढ़ती जा रही है।

वह समाज की गिरावट का ही प्रमाण है कि आज कन्या की श्रेष्ठता, शील, सौंदर्य और गुणों से नहीं बल्कि उसके माँ-बाप के धन से आँकी जाती है। कन्या की कुरूपता दहेज की चमक-दमक में छिप जाती है। दहेज आधुनिक युग में घोर अभिशाप बन गया है । इस सामाजिक कलंक को दूर करने के लिए शिक्षित युवक-युवतियों को आगे आना होगा। सामाजिक संस्थाओं और सरकार को भी इस दशा में कारगर कदम उहाना चाहिए । दहेज प्रथा को दूर करने में महिलाओं की सक्रिय भूमिका अत्यंत महत्त्वपूर्ण है। उन्हें नारियों में जागरूकता, चेतना और दृढ़ इच्छाशक्ति भरनी होगी ताकि नारियाँ इस कुप्रथा के विरुद्ध संघर्ष कर समाज में उचित आदर प्राप्त कर सकें।

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

(घ) आधुनिक भारतीय नारी :
दुनिया के कुछ भागों में यह विश्वास प्रचलित है कि जब परमात्मा ने मानव को उत्पन्न किया तो मानव ने स्वयं को एकाकी पाया, मनुष्य ने परमात्मा से साथी माँगा, परमात्मा ने वायु से शक्ति, सूर्य से गर्मी, हिम से शीत, पारे से चंचलता, तिलियों से सौन्दर्य और मेघ-गर्जन से शोर लेकर स्त्री पुरुष की ‘शरीराद्ध’ और अर्धांगिनी मानी गयी तथा ‘श्री’ और ‘लक्ष्मी’ के रूप में वह मनुष्य के जीवन को सुख और समृद्धि से दीप्त और पुंजित करने वाली कही गयी, उसका आगमन पुरुष के लिए शुभ, सौरभमय और सम्मानजनक था।

हिन्दू समाज में कोई भी धार्मिक कार्य बिना पत्नी के सम्पन्न नहीं होता, इसीलिए वह ‘धर्मपत्नी’ अथवा सहधर्मिणी भी कही जाती है । ‘मनु’ के अनुसार केवल पुरुष कोई वस्तु नहीं, वह अपूर्ण है। स्री, स्वदेह तथा सन्तान ये तीनों ही मिलकर पुरुष (पूर्ण) होता है। गृह की शोभा और सम्पन्नता स्त्री के व्यक्तित्व का विकास एक दूसरे का पूरक है। नारी स्नेह और सौजन्य की प्रतिमा है, त्याग और समर्पण की मूर्ति है, दुष्ट मर्दन में चण्डी, संग्राम में कैकेयी, श्रद्धा में शबरी, सौन्दर्य में दमयन्ती, सुगृहिणी में सीता, अनुराग में राधा, विद्वता में गार्गेयी और राजनीति में लक्ष्मीबाई के तुल्य है। नारी का अपमान मानवता का सबसे बड़ा अपराध है। उसकी उपेक्षा मनुष्य के अस्तित्व को जर्जर, नीरस और व्यर्थ पर देती है।

शिक्षा के प्रसार के साथ-साथ नारी को भी स्वच्छन्द परिवेश में श्वाँस लेने का पूर्णसुखद अवसर सुलभ अवश्य हुआ है किन्तु आर्थिक असमानता, शिक्षा के अभाव में ग्रामीण नारियों का जीवन ‘चूल्हा चक्की’ से ऊपर नहीं उठ सका है और आज भी नारकीय यन्त्रणा ही उनकी हिस्से में है। ‘गृहलक्ष्मी’ तो ये अवश्य है किन्तु तिजोरी की चाभी पुरुष के पास ही रहती है, ‘अन्नूपर्णा’ अवश्य हैं वे किन्तु कौन-सी ‘सब्जी’ बनेगी, पति की ही बात चलती है। धनलोलुपों द्वारा नारी-शरीर का खुला क्रय-विक्रय आज भी सामयिक है। कुछ शहर मर्दो में चाहे वह भाई हो या पति, इस नरक से उबरने की इच्छा भी नहीं मानते । उनका तर्क है कि पेट भरा होने के बाद ही सूझता है कि कौन धंधा सही है, कौन गलत भारत में तमाम शहर ऐसे हैं जहाँ औरतों को आज भी जिन्दा माँस की तश्तरी से ज्यादा महत्त्व नहीं दिया जाता है। हर शहर में वेश्यालय सिनेमा घरों की तरह हाउस-फूल जा रहे हैं। ये वेश्यायें देह सुख के लिए ऐसा नहीं करतीं, अपितु आर्थिक असमानता एवं दुरावस्था से वे अभिशप्त हैं।

भारतीय संस्कृति का परित्याग कर, पश्चिमी अनुकरण कर नारी चैन से नहीं कर सकती है। समाज के साथ-साथ नारी का भी दायित्व है कि अपने प्रति, अपने कर्तव्यों के प्रति, अपने आदर्शों के प्रति सचेष्ट रहे। उसे शकुन्तला भी बनना होगा, सीता भी, राधा भी बनना होगा और लक्ष्मीबाई भी, कस्तूरबा भी, सरोजिनी, नायडू भी। भारतीय नारी का आदर्श महान।

(ङ) विज्ञान: वरदान का अभिशाप :
आज विज्ञान के महत्त्व को, उसको उपादेयता को नकारा नहीं जा सकता है। चाहे वह घर का रसोईघर हो या समर-भूमि; विज्ञान के चमत्कार तथा प्रभाव स्पष्ट रूप से परिलक्षित होते हैं। प्रकृति पर विज्ञान की विजय-यह एक किंवदंती नहीं, एक प्रत्यक्ष सत्य है । चन्द्रमा पर मनुष्य का अभियान, ट्यूब बेबी, रॉकेट, अणुबम आदि विज्ञान की उत्कृष्ट देन हैं। सैकड़ों-हजारों मील लम्बी दूरियाँ भी मनुष्य पैदल ही तय करता था । आज वायुमान के सहारे हम कुछ ही घंटों में भारत से लंदन पहुँच जाते हैं। कभी चन्द्रमा यात्रा की बात कोरी कल्पना समझी जाती थी, परन्तु जब बन्द मानव चन्द्रमा की सतह पर उतरे तो सम्पूर्ण विश्व दाँतों तले ऊँगलियाँ दबाकर रह गया । आज जीवन का कोई भी पक्ष ऐसा नहीं है जहाँ विज्ञान की किरणें नहीं पहुँची हों।

विज्ञान हमारे लिए वरदान सिद्ध हुआ है। इसकी उपयोगिता जीवन के हर क्षेत्र में सिद्ध है। क्षण-क्षण, पल-पल हम विज्ञान के चमत्कारों का नजारा देखते हैं, संबंधित कहानियाँ सुनते हैं। कुछ महत्त्वपूर्ण उपलब्धियों का संकेत करके हम उसके महत्त्व की उपादेयता का सहज अनुभव कर सकते हैं। विज्ञान के अद्भुत चमत्कारों ने एक नयी क्रांति पैदा कर दी है, एक नया अध्याय जोड़ दिया है।

आवागमन के क्षेत्र में विज्ञान की उपलब्धियाँ विशिष्ट एवं विलक्षण हैं। आज से सैकड़ों वर्ष पूर्व एक जगह से दूसरी जगह जाना गहन समस्या था। आज विज्ञान के कारण इस क्षेत्र में क्रान्तिकारी परिवर्तन हुए हैं। रेलगाड़ियाँ, मोटरकार, बसें, वायुयान आदि इतनी तेज सवारियाँ निकल आयी हैं कि बातों-ही-बातों में हम लम्बी-लम्बी दूरियाँ तय कर लेते हैं। तार, टेलीफोन, वायरलेस आदि यंत्रों के आविष्कार के कारण हम घर बैठे मुम्बई, कोलकाता, लंदन में रहनेवाले लोगों से बाते कर लेते हैं। नदी, समुद्र, पहाड़ आज हमारे आवागमन के मार्ग में किसी प्रकार को अवरोध उत्पन्न नहीं कर सकते।

चिकित्सा के क्षेत्र में विज्ञान की उपलब्धियों ने संजीवनी बूटी का काम किया है। पुराने जमाने में छोटी-छोटी बीमारी के कारण लोगों की मृत्यु हो जाती थी।

आज शायद ही ऐसा कई रोग है, जिसकी दवा सुलभ नहीं है, जिसका निदान संभव नहीं है। क्या यह विलक्षण चमत्कार नहीं है कि विश्व से चेचक, प्लेग, मलेरिया आदि रोगों का उन्मूलन हो गया। आज बड़े-बड़े असाध्य रोगों की भी अच्छी एवं प्रभावकारी औषधियाँ निकल रही हैं। दिन-प्रतिदिन नये-नये प्रयोग हो रहे हैं, नये-नये उपकरण एवं नयी-नयी जीवनरक्षक औषधियाँ निकल रही है। मनुष्य का हृदय विकृत या क्षतिग्रस्त हो जाने पर उसे बदल दिया जा सकता है और मनुष्य को नयी जिन्दगी दी जा सकती? अंधे को आँखों की रोशनी, विकलांगों के विकृत अंगों में सुधार, दिल और दिमाग में परिवर्तन वैज्ञानिक चमत्कारों की ही देन हैं।

आवागमन या चिकित्सा ही नहीं, प्रायः सभी क्षेत्रों में विज्ञान की बड़ी-बड़ी उपलब्धियाँ सामने आयी हैं । चन्द्रमा पर मानव की विजय से लेकर पाकशालाओं एवं शयनकक्षों में आराम एवं सुख-सुविधाओं की सारी चीजों की व्यवस्था विज्ञान के ही चमत्कार हैं। रेडियो, सिनेमा, टेलिविजन, वीडियो आदि सारी-की-सारी चीजें विज्ञान की ही देन हैं। कम्प्यूटर ने एक नये युग की शुरूआत की है।

प्रत्येक वस्तु के दो पक्ष होते हैं-श्वेत और श्याम । विज्ञान भी इसका अपवाद नहीं है। विज्ञान यदि वरदान है तो अभिशाप भी बना है। विज्ञान ने यदि हमारे अधरों पर मुस्कुराहट बिखेरी है तो इसने हमारी आँखों में अश्रुकरण भी संजोये हैं। विज्ञान ने परमाणु बम तथा अनेक गैसों, हथियारों एवं शस्त्रास्त्रों का आविष्कार किया है, जो मानव समुदाय का समूल विनाश करते हैं । हिरोशिमा और नागासाकी पर मानवता के ध्वंस का तांडव नृत्य क्या हम भूल पाये हैं ? स्वयं बमपर्षक जहाज के चालकों ने पश्चाताप किया है।

आज बड़े-बड़े देश परमाणु-शक्ति की खोज इसलिए नहीं कर रहे हैं कि उनका प्रयोग मनुष्य के कल्याण एवं शान्तिपूर्ण प्रयोजनों के लिए किया जायेगा, वरन् उनका प्रयोग मानवता को ध्वस्त करने के लिए किया जायेगा। संहार अस्त्र-शस्त्रों के निर्माण पर सभी देश अपनी बजट राशि में वृद्धि कर रहे हैं। बड़े-बड़े देश एवं महाशक्तियाँ इन्हीं संहारक हथियारों के बलबूते पर छोटे तथा कमजोर देश पर अपना आधिपत्य बनाये रखना चाहती है।

इन बमों के विस्फोट से निकली विषैली गैसों के कारण वातावरण दूषित हो गया है, अनेकानेक बीमारियाँ फैल रही हैं। विशेषज्ञों का कथन है कि यदि इसी प्रकार ये विषैली गैसें वातावरण को दूषित करती रही तो आनेवाले बच्चे शारीरिक एवं मानसिक रूप से विकृत होंगे। मशीन के अधिकाअधिक अविष्कार के कारण बेकारी की समस्या बढ़ती जा रही है। जहाँ मशीनों का अधिक उपयोग हो रहा है, वहाँ मनुष्य बेकार होते जा रहे हैं।

विज्ञान एक वरदान भी है और एक अभिशाप भी । विज्ञान अपने-आपमें न तो अभिशाप है और न वरदान । विज्ञान का वरदान होना या अभिशाप होना वैज्ञानिकों और राजनीतिज्ञों पर निर्भर करता है। सबसे मूल बात यह है कि हम इसका प्रयोग किस प्रकार तथा किसलिए करते हैं।

यदि हम विज्ञान का प्रयोग मानव-कल्याण के लिए करते हैं तो हमारे लिए सबसे बड़े वरदान है और यदि हम इसका प्रयोग नर-संहार के लिए करते हैं, तो यह मानव-जीवन का सबसे बड़ा अभिशाप है।

प्रश्न 2.
किन्हीं दो की सप्रसंग व्याख्या करें : (4 x 2 = 8)

(क) आत्महत्या एक घृणित अपराध है । यह पूर्णतः कायरता का कार्य है।
उत्तर:
प्रस्तुत पंक्तियाँ भगत सिंह लिखित कहानी एक लेख और एक पत्र से ली गई हैं। इन पंक्तियों में लेखक कहते हैं, कोई भी व्यक्ति जो आत्महत्या करेगा वह थोड़ा दुख, कष्ट सहने के चलते करेगा। वह अपना समस्त मूल्य एक ही क्षण में खो देगा । इस संदर्भ में उनका विचार है कि मेरे जैसे विश्वास और विचारों वाला व्यक्ति में मरना कदापि सहन नहीं कर सकता । हम तो अपने जीवन का अधिक से अधिक मूल्य प्राप्त करना चाहते हैं। हम मानवता की अधिक से अधिक सेवा करना चाहते हैं। संघर्ष में मरना एक आदर्श मृत्यु है । प्रयत्नशील होना एवं श्रेष्ठ और उत्कृष्ट आदर्श के लिए जीवन दे देना कदापि आत्महत्या नहीं कही जा सकती। आत्महत्या को कायरता’ इसलिए कहते हैं कि केवल कुछ दुखों से बचने के लिए अपने जीवन को समाप्त कर देते हैं । इस संदर्भ में वे एक विचार भी देते हैं कि विपत्तियाँ व्यक्ति को पूर्ण बनाने वाली होती हैं।

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

(ख) नारी और नर एक ही द्रव्य की ढ़ली दो प्रतिमाएँ हैं।
उत्तर:
प्रस्तुत पंक्ति रामधारी सिंह दिनकर के निबंध अर्द्धनारीश्वर से ली गई है। निबंधकार दिनकर का मानना है कि नर-नारी पूर्ण रूप से
समान हैं एवं उनमें एक के गुण दूसरे के दोष नहीं हो सकते । अर्थात् नरों  में नारियों के गुण आएँ तो इससे उनकी मर्यादा हीन नहीं होती बल्कि

उसकी पूर्णता में वृद्धि होती है । दिनकर को यह रूप कहीं देखने को नहीं मिलता है । इसलिए वे क्षुब्ध हैं। उनका मानना है कि संसार में सर्वत्र पुरुष हैं और स्री-स्री । वे कहते हैं कि नारी समझाती है कि पुरुष के गुण सीखने से उसके नारीत्व में बट्टा लगेगा। इसी प्रकार पुरुष समझता है कि त्रियोचित गुण अपनाकर वह ौण हो जायेगा। इस विभाजन से दिनकर दुखी है। यही नहीं भारतीय समाज को जानने वाले तीन बड़े चिंतकों रवीन्द्रनाथ, प्रेमचंद, प्रसाद के चिंतन से भी दुखी हैं । दिनकर मानते हैं कि यदि ईश्वर ने आपस में धूप और चाँदनी का बँटवारा नहीं किया तो हम कौन होते हैं आपसी गुणों को बाँटने वाले ।

(ग) पूरब पश्चिम से आते हैं।
नंगे बूचे नर-कंकाल
सिंहासन पर, बैठा, उनके
तमगे कौन लगाता है।
उत्तर:
प्रस्तुत पंक्तियाँ रघुवीर सहाय की कविता ‘अधिनायक’ से ली गई हैं। कवि भारतीय लोकतांत्रिक व्यवस्था पर साहसपूर्ण प्रतिक्रिया, इसके कथित परिवेश व्यंग्य करता है। भारतीय समाज में फैली अव्यवस्था, ऊँचा-नीच समानता-असमानता पर कलरा कुठाराघात करते हुए पूँजीवादी

जनतंत्र की आड़ में किये जा रहे शोषण, दमन और अन्याय के खिलाफ विद्रोह करता है।

कवि लोकतांत्रिक व्यवस्था पर चोट करते हुए, उस पर कटाक्ष करते हुए कहता है कि इस व्यवस्था में एक तरफ तो चारों दिशाओं से भूख की चीत्कार सुनाई दे रही है, बदन पर पहनने के लिए वस्त्र नहीं है, तो दूसरी ओर सत्ता पर कुंडली मारे लोग शोषण के चक्र चला रहे हैं।

कवि लोकतंत्र के मूल्यों के भ्रष्टीकरण से आहत है। इसीलिए कवि मनुष्य और मनुष्य के बीच समानता और सामाजिक न्याय की लड़ाई के प्रति अपने को प्रतिशत किए हुए है। वह हर ऐसे हर अमानवीय और क्रूर हरकत के खिलाफ आवाज उठाता है जिससे समानता और भाइचारे के जनवादी मूल्य खंडित होते हैं।

(घ) बड़ा कठिन है बेटा खोकर
माँ को अपना मन समझाना।
उत्तर:
प्रस्तुत पंक्तियाँ सुभद्रा कुमारी चौहान की कविता ‘शोक गीत पुत्र वियोग’ से ली गई हैं। इन पंक्तियों में कवयित्री की असीम पुत्र प्रेम की व्यंजना हुई है। कविता माँ का हृदय बड़ा कोमल होता है। वह एक पुत्र को पाने के लिए तरह-तरह की मिन्नतें माँगती हैं। पत्थर को देवता मानकर शीश नचवाती है। नौ माह तक कष्ट झेलती हुई अनेक तकलीफ सहती हुई उसे पाती है । उसे पाने के बाद उसे पढ़ाती-लिखाती, संस्कार देती है। इस तरह पुत्र उसके जीवन का अहम हिस्सा बन जाता है। वह रोता है तो मनाती है, चुप कराती है।

इस तरह पुत्र-प्रेम में वह बँध जाती है। परन्तु इसी बीच जब उसके पुत्र की असमय मृत्यु हो जाती है तो उसका जीवन सूना-सूना हो जाता है । वह पुत्र प्रेम के कारण बेचैन सी हो जाती है। उसे लगता है बिछुड़े हुए पुत्र से एक बार वह मिल लेती, पलभर के लिए प्यार कर लेती । परन्तु यह सब नहीं हो पाता। इसलिए वह मन को समझा नहीं पाती । बेटा खोकर एक माँ को अपने मन को . समझाना कठिन हो जाता है।

प्रश्न 3.
अपने कॉलेज के प्रधानाचार्य को एक आवेदन पत्र लिखें, जिसमें कॉलेज परिसर में हिन्दी-दिवस आयोजित करने की अनुमति की माँग हो। (1 x 5 = 5)

उत्तर:
सेवा में,
प्रधानाचार्य महोदय
पटना कॉलेजिएट स्कूल, पटना ।
श्रीमांगी,

सविनय निवेदन है कि अपने विद्यालय के सभी छात्रों की हारदीक इच्छा है कि विद्यालय परिसर में हिन्दी दिवस आयोजित की जाय । हिन्दी हमारी राष्ट्रभाषा है, हिन्दी की समृद्धि में ही देश की समृद्धि निहित है।

अतः आपसे आग्रह है कि विद्यालय परिसर में हिन्दी दिवस आयोजित करने की अनुमति प्रदान करने की कृपा करें। इसके लिए आपका सदा आभारी रहेंगे।

निवेदन
छात्रगण पटना कॉलेजिएट स्कूल,
पटना
दिनांक 10.02.2019

अथवा
अपने पिताजी को एक पत्र लिखें, जिसमें गर्म कपड़े खरीदने के लिए रुपये की मांग हो।

परीक्षा भवन
……. केन्द्र
10.02.2019

पूज्य पिता जी,
सादर प्रणाम ।

आशा है आप व परिवार के अन्य सभी सदस्य सकुशल और सानन्द होंगे। इस बार मैं आपको पत्र जल्दी न भेज सका क्योंकि मेरी परीक्षा हो रही है। उसी की तैयारी में लगा रहा । इस समय यहाँ भीषण ठंड पर रही है। मेरे पास गर्म कपड़े अपर्याप्त हैं।

अतः गर्म कपड़ा खरीदने के लिए आप मुझे 500 रुपये भेज दें। मेरी ओर से पूज्यमाता जी को सादर चरण वंदना । अशोक और सीमा को प्यार । मेरे योग्य कोई सेवा हो तो अवश्य लिखें। पत्रोत्तर शीघ्र दें तथा रुपये भी जल्दी भिजवाएँ।

आपका सुपुत्र
शशांक सिन्हा

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

प्रश्न 4.
निम्नांकित प्रश्नों में से ‘किन्हीं पाँच के उत्तर दें। (2 x 5 = 10)

(i) भ्रष्टाचार की जड़ क्या है ? क्या आप जे0 पी0 के विचारों से सहमत हैं?
उत्तर:
भ्रष्टाचार की जड़ सरकार की गलत नीतियाँ है । इन गलत नीतियों के कारण भूख है, महँगाई है, भ्रष्टाचार हैं, कोई काम नहीं जनता का निकलता है बगैर रिश्वत दिए । सरकारी दफ्तरों में, बैंकों में, हर जगह, टिकट लेना है उसमें, जहाँ भी हो, रिश्वत के बगैर काम नहीं जनता का होता है। हर प्रकार के अन्याय के नीचे जनता दब रही है। शिक्षा-संस्थाएँ भ्रष्ट हो रही है। हमारे नौजवानों का भविष्य अंधेरे में पड़ा हुआ है । जीवन उनका नष्ट हो रहा है इस प्रकार चारो ओर भ्रष्टाचार व्याप्त है। इसे दूर करने के लिए समाजवादी तरीके से सरकार ऐसी नीतियों बनाएँ जो लोक कल्याणकारी हो।

(ii) अगर मनुष्य में वाशक्ति न होती तो क्या होता?
उत्तर:
हममें वाक्शक्ति न होती तो मनुष्य गूंगा होता, वह मूकबधिर होता। मनुष्य को सृष्टि की सबसे महत्वपूर्ण देन उसकी वाक्शक्ति है। इसी वाक्शक्ति के कारण वह समाज में वार्तालाप करता है। वह अपनी बातों को अभिव्यक्त करता है और उसकी यही अभिव्यक्त वाक्शक्ति भाषा कहलाती है। व्यक्ति समाज में रहता है। इसलिए अन्य व्यक्ति के साथ उसका पारस्परिक सम्बन्ध और कुछ जरूरतें होती हैं जिसके कारण वह वार्तालाप करता है। यह ईश्वर द्वारा दी हुई मनुष्य की अनमोल कृति है। इसी वाक्शक्ति के कारण वह मनुष्य है। यदि हममें इस वाक्शक्ति का अभाव होता तो मनुष्य जानवरों की भाँति ही होता । वह अपनी क्रियायों को अभिव्यक्त नहीं कर पाता । जो हम सुख-दुख इंद्रियों के कारण अनुभव करते हैं वह अवाक् रहने के कारण नहीं कर पाते।

(iii) लहना सिंह कौन है ?
उत्तर:
लहनासिंह एक सामान्य किसान परिवार का है । वह सिपाही की नौकरी करता है और अपने दायित्व के प्रति सजग रहता है।

(iv) मालती कौन थी?
उत्तर:
मालती रोज कहानी की एक पात्रा है। वह एक विवाहित नारी के अभावों में घुटते हुए पंगु बने व्यक्तित्व की प्रतिमूर्ति है।

(v) लहना सिंह के साथी का क्या नाम है ?
उत्तर:
लहना सिंह के साथी का नाम हजारा सिंह है।

(vi) राम का नाम सुनते ही तुलसीदास की बिगड़ी बात बन जाएगी, तुलसीदास के इस भरोसे का कारण स्पष्ट करें ?
उत्तर:
तुलसी कहते हैं कि हे प्रभु मैं अत्यन्त दीन सर्वसाधनों से हीन मनमलीन दुर्बल और पापी मनुष्य हूँ फिर भी आपका नाम लेकर अपना पेट भरता हूँ। तुलसी को यह विश्वास है कि उनके राम कृपालु हैं, दयानिधान हैं वे हर बात को अच्छी तरह समझकर उसका समाधान करते हैं यही उनके भरोसे का कारण है।

(vii) पुत्र के लिए उसकी माँ क्या-क्या करती है ?
उत्तर:
पुत्र के लिए माँ हर कदम पर सचेत होकर चलती है। उसे डर लगा रहता है कि कहीं उसे लू न लग जाए, कहीं उसे सर्दी न लग जाय, उस भय से उसे अपने गोद से भी नहीं उतारती । उसे अपने आँचल की ओट में छिपाये रहती है। जब पुत्र माँ कहकर पुकारता है तो माँ सभी काम छोड़कर दौड़ी चली आती है। पुत्र के न सोने पर उसे थपकी देती है, कभी लोरियाँ गाकर सुलाती है। उसकी आँखें अपने पुत्र के मुख पर मलिनता देखकर रात भर जाग जाती हैं। माँ पुत्र को पाने के लिए मिन्नतें माँगती हैं। कहीं दूध, बताशा, नारियल इत्यादि चढ़ावे के रूप में चढ़ाती हैं। पत्थर जैसे अमूर्त वस्तु को देवता मानकर पुत्र प्राप्ति की इच्छा के लिए मिन्नतें माँगती है। इस तरह पुत्र के लिए माँ का प्रेम असीम है।

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

(viii) ‘राख से लीपा हुआ चौका’ के बारे में कवि का क्या कहना है?
उत्तर:
कवि प्रातः नभ के सौन्दर्य से अभिभूत हो जाता है । उसे सुबह का आकाश मानो ‘राख से लीपा हुआ चौका’ के समान लगता है। आकाश जब सुबह में स्वच्छ रहता है तो ऐसा प्रतीत होता है मानो सारा आकाश राख से लीपे हुए गीले चौके के समान हो गया है।

(ix) ‘जन जन का चेहरा एक’ से कवि का क्या तात्पर्य है ?
उत्तर:
पीड़ितऔर संघर्षशील जनता का, जो अपने मानवोचित अधिकारों के लिए कर्मरत है। यह जनता दुनिया के तमाम देशों में संघर्षरत है और अपने कर्म और श्रम से न्याय, शांति और बंधुत्व की दिशा में प्रयासरत है। कवि इस जनता में एक अंतवर्ती एकता देखता है। इसलिए कवि ‘जन-जन का चेहरा एक’ कहता है।

(x) ‘पद्मावत’ के रचनाकार कौन हैं ?
उत्तर:
पद्मावत के रचनाकार जायसी है।

प्रश्न 5.
निम्नांकित प्रश्नों में से किन्हीं तीन के उत्तर दें : (3 x 5 = 15)

(i) विशनी केवल मानक की माँ नहीं है बल्कि हर सिपाही की माँ है, कैसे?
उत्तर:
एकांकी के दूसरे भाग में विशनी स्वप्न में जो घटना घटती है उसमें जो संवाद होता है उस संवाद से उसमें किसी भी सिपाही की माँ की हँढा तजा सकता है । जब सिपाही मानक को खदेड़ते हुए विशनी के पास ले आता है तो मानक को गले से लिपटी जाता है और सिपाही के पूछने पर कि इसकी तू क्या लगती है विशनी का जबाव आता है-मैं इसकी माँ हूँ। मैं तूझे इसे मारने नहीं दूंगी। तब सिपाही का जबाव आता है यह हजारों का दुश्मन है वे उसको खोज रहे हैं तब विशनी कहती हैं-तू भी तो आदमी है, तेरा भी घर-बार होगा। तेरी भी माँ होगी। तू माँ के दिल को नहीं समझता। मैं अपने बच्चे को अच्छी तरह से जानती हूँ। साथ ही जब मानक का पटलकर सिपाही पर होता है तब विशनी मानक को यह कहती है कि बेटा ! तू इसे नहीं मारेगा । तुझे तेरी माँ की सौगन्ध इसे नहीं मारेगा इन संवादों से पता चलता है कि विशनी मानक को जितना बचाना चाहती है उतना ही उस सिपाही को भी । उसका दिल दोनों के लिए एक है। अतः उसमें किसी भी सिपाही की माँ को ढूँढ़ा जा सकता है।

करते हैं। उनका साहित्य महज आक्रोश और प्रतिक्रिया से परे समता न्याय और मानवीयता पर टिकी नई पूर्णत्तर सामाजिक चेतना और संस्कृति बोध की आहट है। उनके लेखन में अनुभव की सच्चाई और वास्तव बोध से उपजी नवीन रचना संस्कृति की अभिव्यक्ति है । दलित जीवन के रोष और आक्रोष को वे अपने संवेदनात्मक रचनानभवों की भट्ठी में गलाकर रचना की एक नई इनारत पेश करते हैं। जिसका परिप्रेक्ष्य मानवीय है।

(iii) ओ सदानीरा’ का केन्द्रीय भाव लिखें।
उत्तर:
जगदीशचंद्र माथुर ‘ओ सदानीरा’ शीर्षक निबंध के माध्यम से गंडक नदी को निमित्त बनाकर उसके किनारे की संस्कृति और जीवन प्रवाह की अंतरंग झाँकी पेश करते हैं जो स्वयं गंडक नदी की तरह प्रवाहित दिखलाई पड़ता है। सर्वप्रथम चंपारन क्षेत्र की प्राकृतिक वातावरण का वर्णन करते हुए उसकी एक-एक अंग का मनोहारी अंकन करते है। जेसे छायवादी कविताओं में प्रकृति का मानवीकरण देखा जा सकता है उसी तरह निबंध में भी देखा जा सकता है।

एक अंश देखिए-“बिहार के उत्तर-पश्चिम कोण के चंपारण इस क्षेत्र की भूमि पुरानी भी और नवीन भी। हिमालय की तलहटी में जंगलों की गोदी से उतारकर मानव मानो शैशव-सुलभ अंगों और मुस्कान वाली धरती को ठुमक-ठुमककर चलना सिखा रहा है।” इसके साथ माथुर संस्कृति के गर्त में जाकर नदियों में बाढ़ आना उन्हें लगता है जैसे उन्मत्त यौवना वीरांगना हो जो प्रचंड नर्तन कर रही हो। उन्हें साठ-बासठ की बाढ़ रामचरितमानस के क्रोधरूपी कैकयी की तरह दिखलाई पड़ती है। वे बताते हैं नदियों में बाढ़ आना मनुष्यों के उच्छृखलता के कारण हैं। यदि महावन जो चंपारन से गंगा तट तक फैला हुआ था न कटता तो बाढ़ न आती ।

माथुर तर्क देते हैं कि वसुंधराभोगी मानव और धर्मोधमानव एक ही सिक्के के दो पहलू हैं। क्योंकि वसुंधरा भोगी मानव अपने भोग-विलास के लिए जंगलों की कटाई कर रहा है तो धर्मांध मानव पूजा-पाठ के सड़ी गली सामाग्री को गंगा नदी में प्रवाहित कर उसे दूषित कर रहा है। माथुर मध्ययुगीन समाज की सच्चाई भी बताते हैं कि आक्रमण के कारण या अपनी महत्वाकांक्षा की तृप्ति के लिए मुसलमान शासकों ने अंधाधुंध जंगलों की कटाई की । इसी तरह यहाँ अनेक संस्कृति आये और वहीं रच-बस गये। सभी ने उसका दोहन ही किया । इस मिली-जुली संस्कृति का परिणाम कीमियो प्रक्रिया है। चंपारन के प्रत्येक स्थल पर प्राचीन युग में लेकर आधुकिन युग में

है। चंपारन के प्रत्येक स्थल पर प्राचीन युग में लेकर आधुकिन युग में गाँधी के चंपारण आने तक के पूरा इतिहास को अपने लेखनी के माध्यम से अच्छे-बुरे प्रभाव को खंगालते हैं। इस परिचय के संदर्भ में कहीं भी कला संस्कृति उसकी भाषा उनकी आँखों से ओझल नहीं हो पाती। – अंत में गंडककी महिमा का बखान करते हुए कहते हैं कि ओ सदानीरा । ओ चक्रा ! ओ नारायणी । ओ महागंडक ! युगों से दीन-हीन जनता इन विविध नामों से तुझे संबोधित करती रही है। आ तेरे पूजन के लिए जिस मंदिर की प्रतिष्ठित हो रही है, उसकी नींव बहुत गाढ़ी हैं। इसे तू ठुकरा न पाएगी।

Bihar Board 12th Hindi 100 Marks Model Question Paper 1

(iv) कविता की बिंब योजना’ पर टिप्पणी लिखें।
उत्तर:
कविता में शमशेर ने दो तरह के बिंब प्रस्तुत किए हैं जो एक जीवन से जुड़ती हैं जिसे मानवीय व्यापार करते हैं दूसरा प्रकृति से जुड़ता है जिसे प्राकृतिक व्यापार करते हैं। इस प्रकार दोनों को मिलाकर कवि ने प्रकृति का मानवीकरण कर दिया है। यह छायावाद की लक्षण है। शमशेर नयी कविता के कवि हैं और उनमें भी लक्षण दिखाई पड़ते हैं।

कविता का प्रथम वाक्य
प्रात नभ था बहुत नीला शंख जैसे
भोर का नभ।
प्रातः का नभ इतना नीला था कि नीला शंख लग रहा था । शंख जिप प्रकार ध्वनित होता है उसी प्रकार प्रात: में हवा चलने के कारण प्रातः भी ध्वनित होता है।

भोर का नभ-अर्थात् अब सुबह हो रही है सूर्य की लाली दिगन्त में छा गई है। प्रातः के बाद भोर शब्द का प्रयोग गाँव में दिन का शुरुआत के साथ जीवन के कार्य-व्यापार का बिंब खड़ा करता है।

राख से लीपा हआ चौका (अभी गीला पड़ा है

भोर होने के साथ ही गृहिणी पहले चौका लीपती है और उसके बाद कोई कार्य करती है। भोर का आकाश इतना नीला या स्याह है कि लगता है जैसे राख से लीप दिया गया हो । भोर का आकाश अभी गीला इसलिए है कि वह ओसपूर्ण है, उसमें आर्द्रता है।

बहुत काली सिल जरा से लाल केसर से कि जैसे घुल गई हो ।
सुबह चौका लीपने के बाद गृहिनी सिलवट पर मसाला पीसती है। . पीसने के बाद सिलवट धुल जाने पर भी थोड़ी देर के लिए केसर की लालिमा बनी रहती है। उसी प्रकार सूर्योदय होने के पूर्व भी इसी प्रकार आकाश लगता है।

स्लेट पर या लाल खड़िया चाक मल दी हो किसी ने ।
जब सब काम से गृहिणी निवृत्त हो लेती है तब उसका ध्यान बच्चों पर जाता है और बच्चों को वह स्लेट लेकर पढ़ने बैठाती है। बच्चे स्लेट पर खड़िया से लिखने के साथ खूब रगड़ भी देते हैं। प्रकृति के संदर्भ में विंब यह है कि सूर्य की लाली इस प्रकार छा गई है जैसे लाल खड़िया किसी ने मल दी हो।

नील जल में या किसी की गौर
झिलमिल देह जैसे हिल रही हो।
गृहिणी स्नान करती है तब उर्मिला लहरें गौर वर्ण से संयोग कर झिलमिलाती प्रतीत होती हैं। इसी प्रकार सूर्योदय होने पर जल में किरणें पड़ती हैं तो वह झिलमिलाता प्रतीत होता है।

(v) सुभद्रा कुमारी चौहान का जन्म कब और कहाँ हुआ था ?
उत्तर:
सुभद्रा कुमारी चौहान का जन्म सन् 16 अगस्त 1904 ई. को प्रयाग के निहालपुर मुहल्ले में हुआ था। उनका विद्यार्थी जीवन प्रयाग में ही बीता । कास्थवेट गर्ल्स कॉलेज से आपने शिक्षा प्राप्त करने के बाद नवलपुर के सुप्रसिद्ध वकील डॉ. लक्ष्मण सिंह के साथ आपका विवाह हो गया । आपकी रुचि साहित्य में बाल्यकाल से ही थी। प्रथम काव्य रचना

आपने 15 वर्ष की आयु में ही लिखीं थी। राष्ट्रीय आन्दोलन में बराबर सक्रिय भाग लेती रहीं। कई बार जेल गयी। काफी दिनों तक मध्यप्रांत असेम्बली की कांग्रेस सदस्या रहीं और साहित्य एवं राजनीतिक जीवन में समान रूप से भाग लेकर अन्त तक देश की एक जागरूक नारी के रूप में अपना कर्तव्य निभाती रहीं। 1948 ई. में अप्रैल में आपका स्वर्गवास हो गया।

(vi) ‘उषा’ कविता का केन्द्रीय भाव लिखें।
उत्तर:
उषा’ हिन्दी साहित्य के नयी कविता के कवि शमशेर बहादुर सिंह द्वारा रचित प्राकृतिक सौन्दर्यपरक कविता है । इस कविता में कवि ने सूर्यादय के पूर्व के उषाकालीन आकाशीय स्वरूप और सौन्दर्य का मोहक चित्रण किया है। कवि ने इसके चित्रण में भिन्न-भिन्न उपमानों की सहायता भी ली है।

सूर्योदय के पूर्व का काल उषाकाल कहलाता है । उस समय आकाश बिल्कुल नीला और स्वच्छ रहता है। उसकी नीलिमा के बीच आनेवाला उजाला हल्के रूप में झाँकता-सा नजर आता है । प्रातः काल की उस वेला में आकाश नीले राख-सा लगता है। हल्के अंधकार के आवरण में बँके रहने के कारण संपूर्ण आकाश राख से लीपे हुए गीले चौक के समान लगता है।

फिर, धीरे-धीरे सूर्य की हल्की लालिमा की झलक उभरने लगती है। तब उसका स्वरूप कुछ बदल-सा जाता है और उस समय आकाश को देखकर ऐसा लगता है कि आकाश वह काली सिल हो जो जरा-सा लाल केसर से धुली हुई हो या वैसा स्लेट ही जिसपर खड़ियां चाक मल दी गई हो । अंत में कवि ने उषाकालीन आकाश के प्राकृतिक सौन्दर्य को प्रभावपूर्ण रूप से प्रस्तुत करने के लिए अंतिम उपमान लगाकर चर्चा करते हुए कहा है कि उस समय आकाश के वक्ष पर उषा कालीन दृश्य ऐसा लगता है मानो नीले जल में झिलमिलाती गोरी कोई काया खड़ी हो ।

इसी परिवेश में सूर्योदय होता है। फिर सूर्य की किरणें विकीर्ण होने लगती हैं और आकाश की गोद में चल रहा उषा का यह जादू और उसका नजारा सब समाप्त हो जाता है।

प्रश्न 6.
संक्षेपण करें: (1 x 4 = 4)

दूसरों की निन्दा करने का एक प्रमुख कारण दूसरे के प्रति ईर्ष्या-द्वेष भी होता है। कुछ लोग ईर्ष्या-द्वेष से दूसरों की निंदा करते हैं । इस प्रकर की निंदा सरस होती है। उसमें आनंद नहीं आता । निंदा करने का जो आनंद समर्पित भाव से निंदा करने में आता है, वह ईर्ष्या-द्वेष रखकर निंदा करने में नहीं आता है। निन्दा करने वाला सदा दुखी और अशान्त रहता है। उससे दूसरों की उन्नति, प्रगति सुख, समृद्धि सहन नहीं होती । अपनी असमर्थता और हीनता के कारण उसमें ईर्ष्या-द्वेष उत्पन्न होता है। दूसरों की निन्दा करने पर उसे थोड़ी-सी शान्ति मिलती है। ऐसा निन्दक दया का पात्र होता है।
उत्तर:
शीर्षक-निन्दा ईर्ष्या-द्वेष से प्रेरित होकर दूसरी की निन्दा करते हैं जो सरल नहीं होती है। लेकिन समर्पित भाव से निन्दा करने में आनन्द आता है। निन्दक सदा दुःखी और अशांत रहता है। उससे दूसरे की अच्छाई सहन नहीं होती है।

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Bihar Board 12th Physics Objective Questions and Answers

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 1.
In Geiger-Marsden scattering experiment, the trajectory traced by an a-particle depends on
(a) number of collision
(b) number of scattered a-particles
(c) impact parameter
(d) none of these
Answer:
(c) impact parameter

Question 2.
In the Geiger-Marsden scattering experiment, in case of head-on collision the impact parameter should be
(a) maximum
(b) minimum
(c) infinite
(d) zero
Answer:
(b) minimum

Question 3.
Rutherford’s experiments suggested that the size of the nucleus is about
(a) 10-14 m to 10-12 m
(b) 10-15 m to 10-13 m
(c) 10-15 m to 10-14 m
(d) 10-15 m to 10-12 m
Answer:
(c) 10-15 m to 10-14 m

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 4.
In an atom the ratio of radius of orbit of electron to the radius of nucleus is
(a) 103
(b) 104
(c) 105
(d) 106
Answer:
(c) 105

Question 5.
The volume occupied by an atom is greater than the volume of the nucleus by a factor of about
(a) 101
(b) 105
(c) 1010
(d) 1015
Answer:
(d) 1015

Question 6.
The first spectral series was discovered by
(a) Balmer
(b) Lyman
(c) Paschen
(d) Pfund
Answer:
(a) Balmer

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 7.
Which of the following spectral series falls within the visible range of electromagnetic radiation?
(a) Lyman series
(b) Balmer series
(c) Paschen series
(d) Pfund series
Answer:
(b) Balmer series

Question 8.
The shortest wavelength present in the Paschen series of spectral lines is
(a) 720 nm
(b) 790 nm
(c) 800 nm
(d) 820 nm
Answer:
(d) 820 nm

Question 9.
The shortest wavelength in the Balmer series is (R = 1.097 x 107 m-1)
(a) 200 nm
(b) 256.8 nm
(c) 300 nm
(d) 364.6 nm
Answer:
(d) 364.6 nm

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 10.
The wavelength limit present in the Pfund series is (R = 1.097 x 107 m s-1)
(a) 1572 nm
(b) 1898 nm
(c) 2278 nm
(d) 2535 nm
Answer:
(c) 2278 nm

Question 11.
When an electron jumps from the fourth orbit to the second orbit, one gets the
(a) second line of Paschen series
(b) second line of Balmer series
(c) first line of Pfund series
(d) second line of Lyman series
Answer:
(b) second line of Balmer series

Question 12.
When an atomic gas or vapour is excited at low pressure, by passing an electric current through it then
(a) emission spectrum is observed
(b) absorption spectrum is observed
(c) band spectrum is observed
(d) both (b) and (c)
Answer:
(a) emission spectrum is observed

Question 13.
In Balmer series of emission spectrum of hydrogen, first four lines with different wavelength Ha, Hp, Hy and H5 are obtained. Which line has maxium frequency out of these?
(a) Hα
(b) Hβ
(c) Hγ
(d) Hδ
Answer:
(d) Hδ

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 14.
Hydrogen atom emits light when it changes from n = 5 energy level to n =2 energy level. Which colour of light would the atom emit?
(a) red
(b) yellow
(c) green
(d) violet
Answer:
(d) violet

Question 15.
The wavelength of the first line of Lyman series is 1215 kA, the wavelength of first line of Balmer series will be
(a) 4545 A
(b) 5295 A
(c) 6561 A
(d) 6750 A
Answer:
(c) 6561 A

Question 16.
According to Bohr’s theory, the wave number of last line of Balmer series is (R = 1.1 x 107 m-1)
(a) 5.5 x 105 m-1
(b) 4.4 x 107 m-1
(c) 2.75 x 106 m-1
(d) 2.75 x 108 m-1
Answer:
(c) 2.75 x 106 m-1

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 17.
What is the ratio of the shortest wavelength of the Balmer series to the shortest wavelength of the Lyman series?
(a) 4 : 1
(b) 4 : 3
(c) 4 : 9
(d) 5 : 9
Answer:
(a) 4 : 1

Question 18.
The Bohr model of atoms
(a) assumes that the angular momentum of electrons is quantized.
(b) uses Einstein’s photoelectric equation.
(c) predicts continuous emission spectra for atoms.
(d) predicts the same emission spectra for all types of atoms.
Answer:
(a) assumes that the angular momentum of electrons is quantized.

Question 19.
The angular speed of the electron in the nth orbit of Bohr’s hydrogen atom is
(a) directly proportional to n
(b) inversely proportional to \(\sqrt{n}\)
(c) inversely proportional to n2
(d) inversely proportional to. n3
Answer:
(d) inversely proportional to. n3

Question 20.
The moment of momentum for an electron in second orbit of hydrogen atom as per Bohr’s model is
\((a) \frac{h}{\pi}
(b) 2 \pi h
(c) \frac{2 h}{\pi}
(d) \frac{\pi}{h}\)
Answer:
\((a) \frac{h}{\pi}\)

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 21.
According to second postulate of Bohr model, the angular momentum (Ln) of nth possible orbit of hydrogen atom is given by
Answer:
(b)

Question 22.
The total energy (En) of the electron in the stationary states in the nth orbit of the hydrogen atom is
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 1
Answer:
(b)

Question 23.
The radius of nth orbit rn in terms of Bohr radius (a0) for a hydrogen atom is given by the relation
\((a) n a_{0}
(b) \sqrt{n} a_{0}
(c) n^{2} a_{0}
(d) n^{3} a_{0}\)
Answer:
\((c) n^{2} a_{0}\)

Question 24.
In the Bohr model of the hydrogen atom, the lowest orbit corresponds to
(a) infinite energy
(b) maximum energy
(c) minimum energy
(d) zero energy
Answer:
(c) minimum energy

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 25.
The value of ionisation energy of the hydrogen atom is
(a) 3.4 eV
(b) 10.4eV
(c) 12.09 eV
(d) 13.6 eV
Answer:
(d) 13.6 eV

Question 26.
Energy is absorbed in the hydrogen atom giving absorption spectra when transition takes place from
(a) n = 1 → n’ where n >1
(b) n = 2 → 1
(c) n → n
(d) n → n’ = ∞
Answer:
(a) n = 1 → n’ where n >1

Question 27.
In which of the following systems will the radius of the first orbit (n –1) be minimum?
(a) doubly ionized lithium
(b) singly ionized helium
(c) deuterium atom
(d) hydrogen atom
Answer:
(a) doubly ionized lithium

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 28.
When an electron falls from a higher energy to a lower energy level the difference in the energies appears in the form of
(a) electromagnetic radiation only
(b) thermal radiation only
(c) both electromagnetic and thermal radiations
(d) none of these
Answer:
(a) electromagnetic radiation only

Question 29.
From quantisation of angular momentum, one gets for hydrogen atom, the raius of the nth orbit as
\(r_{n}=\left(\frac{n^{2}}{m_{e}}\right)\left(\frac{h}{2 \pi}\right)^{2}\left(\frac{4 \pi^{2} \varepsilon_{0}}{e^{2}}\right)\)
For a hydrogen like atom of atomic number Z,
(a) the radius of the first orbit will be same
(b) rn will be greater for larger Z values
(c) rn will be smaller for larger Z values
(d) none of these
Answer:
(c) rn will be smaller for larger Z values

Question 30.
If E is the energy of nth orbit of hydrogen atom the energy of nth orbit of He atom will be
(a) E
(b) 2E
(c) 3E
(d) 4E
Answer:
(d) 4E

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 31.
In which of the following Bohr’s orbit (n) a hydrogen atom emits the photons of lowest frequency?
(a) n = 2 to n = 1
(b) n = 4 to n = 2
(c) n = 4 to n = 1
(d) n = 4 to n = 3
Answer:
(d) n = 4 to n = 3

Question 32.
If an electron is revolving in its Bohr orbit having Bohr radius of 0.529 A, then the radius of third orbit is
(a) 4234 nm
(b) 4496 A
(c) 4.761 A
(d) 5125nm
Answer:
(c) 4.761 A

Question 33.
The energy required to excite an electron in hydrogen atom to its first excited state is
(a) 8.5eV
(b) 10.2eV
(c) 12.7eV
(d) 13.6eV
Answer:
(b) 10.2eV

Question 34.
A triply ionized beryllium (Be3+) has the same orbital radius as the ground state of hydrogen. Then the quantum state n of Be3+ is
(a) n = 1
(b) n = 2
(c) n = 3
(d) n = 4
Answer:
(b) n = 2

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 35.
The ground state energy of hydrogen atom is -13.6 e V. The kinetic of the electron in this state is
(a) 2.18 x I0-14 J
(b) 2.18 x 10-16 J
(c) 2.18 x 10-18 J
(d) 2.18 x 10-19 J
Answer:
(c) 2.18 x 10-18 J

Question 36.
If the radius of inner most electronic orbit of a hydrogen atom is 5.3 x 10-11 m, then the radii of n = 2 orbit is
(a) 1.12 A
(b) 2.12 A
(c) 3.22 A
(d) 4.54 A
Answer:
(b) 2.12 A

Question 37.
A hydrogen atom initially in the ground level absorbs a photon and is excitied to n = 4 level then the wavelength of photon is
(a) 790 A
(b) 870 A
(c) 970A
(d) 1070 A
Answer:
(b) 870 A

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 38.
If speed of electron in ground state energy level is 2.2 x 106 m s-1, then its speed in fourth excited state will be
(a) 6.8 x 106 m s-1
(b) 8.8 x 106 m s-1
(c) 5.5 x 105 m s-1
(d) 5.5 x 106 m s-1
Answer:
(c) 5.5 x 105 m s-1

Question 39.
An electron is revolving in the /Ith orbit of radius 4.2 A, then the value of n is (r1 = 0.529 A)
(a) 4
(b) 5
(c) 6
(d) 3
Answer:
(d) 3

Question 40.
The ratio of the speed of the electron in the ground state of hydrogen atom to the speed of light in vacuum is
\((a) \frac{1}{2}
(b) \frac{2}{237}
(c) \frac{1}{137}
(d) \frac{1}{237}\)
Answer:
\((c) \frac{1}{137}\)

Question 41.
The binding energy of an electron in the ground state of He is equal to 24.6 eV. The energy required to remove both the electrons is
(a) 49.2 eV
(b) 54.4eV
(c) 79eV
(d) 108.8 eV
Answer:
(c) 79eV

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 42.
The ionization energy of Li++ is equal to
(a) 9 hcR
(b) 6 hcR
(c) 2 hcR
(d) hcR
Answer:
(a) 9 hcR

Question 43.
The de-Broglie wavelength of an electron in the first Bohr orbit is
(a) equal to one-fourth the circumference of the first orbit
(b) equal to half the circumference of first orbit
(c) equal to twice the circumference of first orbit
(d) equal to the circumference of the first orbit
Answer:
(d) equal to the circumference of the first orbit

Question 44.
The excitation energy of Lyman last line is
(a) the same as ionisation energy
(b) the same as the last absorption line in Lyman series
(c) both (a) and (b)
(d) different from (a) and (b)
Answer:
(c) both (a) and (b)

Question 45.
The number of de Broglie wavelengths contained in the second Bohr orbit of Hydrgen atom is
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(b) 2

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 46.
If there are N atoms in a source of Laser light and each atom is emitting light with intensity I, then the total intensity produced by it is
(a) NI
(b) N2I
(C) N3I
(d) N4I
Answer:
(b) N2I

Question 47.
The acronym LASER stands for
(a) Light Amplification by Stimulated Emission of Radiation
(b) Light Amplitude by Stimulated Emission of Radiation
(c) Light Amplification by Strong Emission of Radiation
(d) Light Amplification by Stimulated Emission of Radiowave
Answer:
(a) Light Amplification by Stimulated Emission of Radiation

Question 48.
Two H atoms in the ground state collide inelastically. The maximum amount by which their combined kinetic energy is reduced is
(a) 10.2 eV
(b) 20.4eV
(c) 13.6eV
(d) 27.2eV
Answer:
(a) 10.2 eV

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Hints & Explanations

Question 4.
(c) The radius of orbit of electrons = 10-10 m radius of nucleus = 10-15 m
Ratio = \(=\frac{10^{-10}}{10^{-15}}=10^{5}\)
Hence the radius of electron orbit is 105 times larger than the radius of nucleus.

Question 5.
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 2

Question 8.
(d) The wavelength for Paschen series,
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 3
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 4

Question 9.
(d) Wavelength for Balmer series is \(\frac{1}{\lambda}=R\left(\frac{1}{2^{2}}-\frac{1} at n = ∞, the limit of the series observed.
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 5

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 10.
(c) The wavelength for Pfund series is given by
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 6

Question 15.
(c) Here, λL. = 1215 A, For the first line of Lyman series.
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 7

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 20.
(a) According to Bohr’s second postulate Angular momentum, [latex]L=\frac{n h}{2 \pi}\)

Angular momentum is also called a moment of momentum.

For second orbit, n = 2 \(L=\frac{2 h}{2 \pi}=\frac{h}{\pi}\)

Question 23.
(c) The radius of nth orbit rn = n2 \(\frac{\hbar^{2} 4 \pi \varepsilon_{0}}{m e^{2}}\) where \(\frac{\hbar^{2} 4 \pi \varepsilon_{0}}{m e^{2}}=a_{0}[/ltaex] (Bohr radius)
Hence, rn = n2 a0.

Question 30.
(d) Since Bohr’s formula for energy in nth orbit is
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 8

Question 31.
(d) The energy level diagram schematically looks like this. As we move to higher and higher levels, the energy increases, but the energy gap between any two levels decreases. Hence in the transition from n = 4 to n = 3, energy released will be E4 – E3.
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 9

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms
And in the transition from n = 2 to n – 1, energy released is E2 -E1.
Now as E4 – E3 < E2 – E1

[latex]\Rightarrow h v_{43}<h v_{21} \Rightarrow h v_{43}<h v_{21}\)

Question 32.
(c) As rn = n2 a0
Here, a0 = 0.529 A and n = 3
.-. rn=3 = (3)3 a0 = 9 x 0.529A = 4.76lA

Question 33.
(b) Energy, \(E_{n}=-\frac{13.6}{n^{2}} \mathrm{eV}\)
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 10

Question 34.
(b) Radius of nlh orbit in hydrogen like atom is
\(r_{n}=\frac{a_{0} n^{2}}{Z}\)

where a0 is the Bohr’s radius For hydrogen atom, Z= 1
∴ r1 = a0 (∵ n = 1 for ground state) 2
For \(\mathrm{Be}^{3+}, \mathrm{Z}=4 ∴ r_{n}=\frac{a_{0} n^{2}}{4}\)
According to given problem \(r_{1}=r_{n} \Rightarrow a_{0}=\frac{n^{2} a_{0}}{4}\)
⇒ n = 2

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 35.
(c) Here the ground state energy, (E) = – 13.6 eV
Since, K.E. of the electron = -E = 13.6 eV
= 13.6 x 1.6 x 10-19 J
= 21.76 x 10-19 J
= 2.18 x 10-18 J.

Question 36.
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 11

Question 37.
(c) Here, = 1, and n2 = 4
Energy of photon absorbed, E = E2 – E1
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 12

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 38.
(c) According to Bohr’s model \(v=\frac{2 \mathrm{Ke}^{2} \mathrm{Z}}{n h} \text { or } v \propto \frac{1}{n}\)
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 13

Question 39.
Bihar Board 12th Physics Objective Answers Chapter 12 Atoms in english medium 14

Question 40.
(c) Speed of the electron in the ground state of hydrogen atom is
\(v=\frac{2 \pi e^{2}}{4 \pi \varepsilon_{0} h}=\frac{c}{137}=c \alpha\)

where, c = speed of light in vacuum, \(\alpha=\frac{e^{2}}{2 \varepsilon_{0} h c}\) the fine structure constant. It is a pure number whose value is \(\frac{1}{137}\).

∴ \(\frac{v}{c}=\frac{1}{137}\)

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Question 41.
(c) The energy needed to remove one electron from the ground state of He = 24.6 eV.
As the He+ is now hydrogen-like, ionisation energy
\(=|-13.6| \frac{2^{2}}{1^{2}} \mathrm{eV} \Rightarrow \mathrm{E}=54.4 \mathrm{eV}\)

∴ To remove both the electrons, energy needed = (54.4 + 24.6) eV = 79. eV

Question 48.
(a) In inelastic collision kinetic energy is not conserved so some part of K.E. is lost.

∴ Reduction in K.E. = K.E. before collision – K.E. after collision
Now, since initial K.E. of each of two hydrogen atoms in ground state = 13.6 eV
Total K.E. of both Hydrogen atom before collision = 2x 13.6 = 27.2 eV
If one H atom goes over to first excited state (n1 = 2) and other remains in ground state (n2 = 1) then their combined K.E. after collision is
\(=\frac{13.6}{(2)^{2}}+\frac{13.6}{(1)^{2}}=3.4+13.6=17 \mathrm{eV}\)
Hence reduction in K.E. = 27.2 – 17 = 10.2 eVA

Bihar Board 12th Physics Objective Answers Chapter 12 Atoms

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Bihar Board 12th Chemistry Objective Questions and Answers

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 1.
Which of the following example is not correctly matched ?
(a) Two most abudant elements-Fe, Al
(b) Two metals which occur in native state-Au, Pt
(c) Two metals which can occur in combined and native state both-Zn,Fe.
(d) None of these
Answer:
(c) Two metals which can occur in combined and native state both-Zn,Fe.

Question 2.
Which of the following is not the correct name of the formula of the ore given with it ?
(a) MgSO4.7H2O – Epsom salt
(b) CuCO3.Cu(OH)2 – Malachite
(c) KAlSi3O8-Feldspar
(d) MgCl2.6H2O – Dolomite
Answer:
(d) MgCl2.6H2O – Dolomite

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 3.
In which of the following the name of the ore is not matched with its formula ?
(a) Cassiterite – SnO2
(b) Limonite – FeCO3 . 3H2O
(c) Siderite – FeCO3
(d) Anglesite – PbCO3
Answer:
(d) Anglesite – PbCO3

Question 4.
Pyrolusite is …..
(a) a suiphide ore of Mn
(b) an oxide ore of Mn
(c) a carbide ore of P
(d) a chloride ore of Zn
Answer:
(d) a chloride ore of Zn

Question 5.
The name of the metal which is extracted from the ore is given below. Mark the example which is not correct.
(a) Malachite – Cu
(b) Calamine – Zn
(c) Chromite – Cr
(d) Dolomite – Al
Answer:
(d) Dolomite – Al

Question 6.
Which of the followings is magnetite ?
(a) Fe2CO3
(b) Fe2O3
(c) Fe3O4
(d) Fe2O3.3H2O
Answer:
(c) Fe3O4

Question 7.
Which of the following is not an ore of magnesium ?
(a) Camallite
(b) Magnesite
(c) Dolomite
(d) Gypsum
Answer:
(d) Gypsum

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 8.
Which of the following is not an oxide ore ?
(a) Corundum
(b) Zincite
(c) Calamine
(d) Chromite
Answer:
(c) Calamine

Question 9.
Which one of the following is not a sulphide ore ?
(a) Galena
(b) Iron pyrites
(c) Magnetite
(d) Copper glance
Answer:
(c) Magnetite

Question 10.
Which of the following is a halide ore ?
(a) Cassiterite
(b) Anglesite
(c) Siderite
(d) Camallite
Answer:
(d) Camallite

Question 11.
Which of the following is not a carbonate ore ?
(a) Dolomite
(b) Calamine
(c) Siderite
(d) Zincite
Answer:
(d) Zincite

Question 12.
Find the incorrect match.
(a) Kaolinite – [Al2(OH)4 Si2O5]
(b) Siderite – Fe2O3
(c) Sphalerite – Zns
(d) Magnetite – Fe3O4
Answer:
(b) Siderite – Fe2O3

Question 13.
Which of the following ores cannot be concentrated by magnetic spearation ?
(a) Haematite
(b) Malachite
(c) Magnetite
(d) Siderite
Answer:
(b) Malachite

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 14.
An ore of tin containing, FeCr04 is concentrated by
(a) gravity separation
(b) magnetic separation
(c) froth floatation
(d) leaching
Answer:
(b) magnetic separation

Question 15.
Sulphide ore of zinc/copper is concentrated by
(a) floatation process
(b) electromagnetic proess
(c) gravity separation
(d) distillation
Answer:
(a) floatation process

Question 16.
For which of the following ores froth floatation method is used for concentration ?
(a) Haematite
(b) Zinc blende
(c) Magnetite
(d) Camallite
Answer:
(b) Zinc blende

Question 17.
The oil used as frothing agent in froth floatation process is ………….
(a) coconut oil
(b) castor oil
(c) palmitic oil
(d) pine oil
Answer:
(d) pine oil

Question 18.
How do we separate two sulphide ores by froth floatation method ?
(a) By using excess of pine oil
(b) By adjusting proportion of oil to water or using depressant
(c) By using collectors and froth stabilisers like xanthates
(d) By using some solvent in which one of the sulphides is soluble
Answer:
(b) By adjusting proportion of oil to water or using depressant

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 19.
Common impurities present in bauxite are
(a) CuO
(b) ZnO
(c) CaO
(d) SrO2
Answer:
(d) SrO2

Question 20.
Which of the following reactions does not take place during leaching for concentration of bauxite ?
(a) Al2O3 + 2NaOH + 3H2O → 2Na[Al(OH)4]
(b) 2Na[Al(OH)4]+CO2 → Al2O3.xH2O + 2NaHCO3
Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements 1

Answer:
(c) Al2O3.2H2O → Al2O3 + 2H2O

Question 21.
The significance of leaching in the extraction of aluminium is
(a) it helps removing the impurities like SiO2, Fe2O3, etc from the bauxite ore
(b) it converts the ore into oxide
(c) it reduces melthing point of the ore
(d) it eliminates water from bauxite
Answer:
(a) it helps removing the impurities like SiO2, Fe2O3, etc from the bauxite ore

Question 22.
Which of the following metals is not extracted by leaching ?
(a) Aluminium
(b) Mercury
(c) Silver
(d) Gold
Answer:
(b) Mercury

Question 23.
Heating pyrites to remove sulphur is called ……………….
(a) smelting
(b) calcination
(c) liquation
(d) roasting
Answer:
(d) roasting

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 24.
Which of the following is not an example of roasting ?
(a) 2ZnS + 3O2 → 2ZnO + 2SO2
(b) 2PbS + 3O2 → 2PbO + 2SO2
(c) 2Cu → S + 3O2 → 2Cu2O + 2SO2
(d) 2Cu2O + Cu2S → 6Cu + SO2
Answer:
(d) 2Cu2O + Cu2S → 6Cu + SO2

Question 25.
Which of the following metals is extracted using a silica lined convertor ?
(a) Mg
(b) Al
(c) Cu
(d) Zn
Answer:
(c) Cu

Question 26.
Which of the following reactions show the process of smelting ?
(a) 2PbO + PbS → 3Pb + SO2
(b) 2Na[Au(CN)2] + Zn → Na2[Zn(CN)4] + 2Au
(c) PbO + CPb + CO
(d) 2HgS + 3O2 → 2HgO + 2SO2
Answer:
(c) PbO + CPb + CO

Question 27.
Which of the following sulphides when heated strongly in air gives the corresponding metal without undergoing separate reduction of oxide ?
(a) Cu2S
(b) FeS
(c) HgS
(d)ZnS
Answer:
(c) HgS

Question 28.
Ellingham diagram represents change of
(a) ΔG With temperature
(b) ΔH with temperature
(c) ΔG with pressure
(d) (ΔG -TΔS) with temperature
Answer:
(a) ΔG With temperature

Question 29.
Which of the following reactions takes place at higher temperature range (900 K-1500 K) in blast furnace ?
(a) 3Fe2O3 + PCO → 2Fe3+CO2
(b) FeO + CO → Fe + CO2
(c) Fe3O4 +4CO → 3Fe + 4CO2
(d) Fe2O3 + CO → 2FeO + CO2
Answer:
(a) 3Fe2O3 + PCO → 2Fe3+CO2

Question 30.
During the extraction of heematite, limestone is added which acts as
(a) flux
(b) slag
(c) reducing agent
(d) gangue
Answer:
(a) flux

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 31.
Which of the following stage is produced during extraction of iron ?
(a) CaSiO3
(b) FeSiO3
(c) MgSiO3
(d)ZnSiO3
Answer:
(a) CaSiO3

Question 32.
Wrought iron is manufactured from cast iron by heathing it with
(a) C
(b) CaCO3
(c) Fe2O3
(d) SiO2
Answer:
(c) Fe2O3

Question 33.
In blast furnace iron oxide is reduced by
(a) silica
(b) carbon monoxide
(c) carbon
(d) lime stone
Answer:
(b) carbon monoxide

Question 34.
Blister copper is …………..
(a) impure copper
(b) obtained in self-reduction process during bessemerisation
(c) Both are correct
(d) None is correct
Answer:
(c) Both are correct

Question 35.
From the Ellingham graph between Gibb’s energy and temperature, out of C and CO which is a better reducing agent for ZnO ?
(a) Carbon
(b) CO
(c) Both of these
(d) None of these
Answer:
(a) Carbon

Question 36.
In a thermite process………. is used as reducing agent.
(a) Zn
(b) Al
(c) Mn
(d) Fe
Answer:
(b) Al

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 37.
In metallurgical process, aluminium acts as …………………
(a) an oxidising agent
(b) basic flux
(c) acidic flux
(d) basic flux
Answer:
(b) basic flux

Question 38.
Which of the following metals cannot be obtained by reduction of its metal oxide by aluminium ?
(a) Cr
(b) Mn
(c) Fe                   ’
(d) Mg
Answer:
(d) Mg

Question 39.
Which of the following metals is obtained by electrolytic reduction process ?
(a) Fe
(b) Cu
(c) Ag
(d) Al
Answer:
(d) Al

Question 40.
Cryolite and fluorspar are mixed with Al2O3 during ‘ electrolysis for extraction of aluminium to
(a) increases the mass of the reaction mixture
(b) get other products at anode like fluorine
(c) lower the melting point and increase the conductivity of the electrolyte
(d) reduce aluminium oxide by cryolite
Answer:
(c) lower the melting point and increase the conductivity of the electrolyte

Question 41.
Which of the following metals cannot be obtained by electrolysis ?
(a) Cr
(b) Na
(c) Ca
(d) Mg
Answer:
(a) Cr

Question 42.
Extraction of chlorine from brine is based on
(a) reduction
(b) displacement
(c) oxidation
(d) evaporation
Answer:
(c) oxidation

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 43.
…. being highly reactive is used in the extraction of chromium and manganese.
(a) Al
(b) Zn
(c) Cu
(d) Mg
Answer:
(a) Al

Question 44.
Which of the following is not a method of refining of metals ?
(a) Electrolysis
(b) Semlting
(c) Poling
(d) Liquation
Answer:
(b) Semlting

Question 45.
Most electropositive metals are obtained from their ores by ………….
(a) autoreduction
(b) smelting with carbon
(c) electrolysis of fused salts
(d) thermal decomposition
Answer:
(c) electrolysis of fused salts

Question 46.
Which one of the following is true in electrolytic refining ?
(a) Impure metal is made cathode
(b) Impure metal is made anode
(c) Impure metal is made cathode and pure metal as anode
(d) Both electrodes must be of pure metal
Answer:
(b) Impure metal is made anode

Question 47.
Carnallite on electrolysis gives ………..
(a) Mg and CI2
(b) Ca and Cl2
(c) K and Cl2
(d) Al and Cl2
Answer:
(c) K and Cl2

Question 48.
In electro-refining of copper, some gold is deposited as
(a) cathode mud
(b) electrolyte
(c) anode mud
(d) cathode
Answer:
(c) anode mud

Question 49.
During the process of electrolytic refining of copper, some metals present as impurity settle as ‘anode mud’. These are
(a) Sn and Ag
(b) Pb and Zn
(c) Ag and Au
(d) Fe and Ni
Answer:
(c) Ag and Au

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 50.
Which of the following is used as a method of purification for silicon ?
(a) Electrolytic refining
(b) Liquation
(c) Zone refining
(d) Distillation
Answer:
(c) Zone refining

Question 51.
Impure
Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements 2
The above process of purification of the metal is known as
(a) van Arkel process
(b) pyrometallurgy
(c) Mond process
(d) zone refining
Answer:
(b) pyrometallurgy

Question 52.
Which process of purification is represented by the following reaction
Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements 3
(a) Zone refining
(b) Mond’s process
(c) Cupellation
(d) van Arkal process
Answer:
(c) Cupellation

Bihar Board 12th Chemistry Objective Answers Chapter 6 General Principles and Processes of Isolation of Elements

Question 53.
Chromatography is a useful method for purification of elements which are
(a) very reactive
(b) available in minute quantities
(c) present in abundance
(d) highly electropositve
Answer:
(b) available in minute quantities

Question 54.
A number of elements are available in earth’s crust but most abundant elements are……………..
(a) Al and Fe
(b) Al and Cu
(c) Fe and Cu
(d) Cu and Ag
Answer:
(a) Al and Fe

Question 55.
In the extraction of copper from its sulphide ore, the mental is formed by the reduction of Cu2O with………………….
(a)FeS
(b)CO
(c) Cu2S
(d) SO2
Answer:
(c) Cu2S

Question 56.
Electrolytic refining is used to purify which of the following metals ?
(a) Cu and Zn
(b) Ge and Si
(c) Zr and Ti
(d) Zn and Hg
Answer:
(a) Cu and Zn

Question 57.
Below point ‘A’ FeO can_________
(a) be reduced by carbon monoxide only
(b) be redued by both carbon monoxide and carbon
(c) be reduced by carbon only
(d) not be reduced by both carbon and carbon monoxide
Answer:
(a) be reduced by carbon monoxide only

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Bihar Board 12th Biology Objective Questions and Answers

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 1.
Microbes are present in
(a) soil
(b) thermal vents
(c) polluted water
(d) all of these
Answer:
(d) all of these

Question 2.
Which of the following microbes is a proteinacious infectious agent ?
(a) Fungi
(b) Prions
(c) Bacteria
(d) Protozoa
Answer:
(b) Prions

Question 3.
The nutritive medium for growing bacteria and many fungi in laboratory is called
(a) growth media
(b) suspension media
(c) culture media
(d) colonial media
Answer:
(c) culture media

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 4.
The inoculum is added to the fresh milk in order to convert milk into curd, the term ‘inoculum’ here refers to
(a) a starter rich in vitami Bp
(b) a starter rich in proteins
(c) a starter containing milions of LAB
(d) an aerobic digester
Answer:
(c) a starter containing milions of LAB

Question 5.
Which of the following organisms is used in the production of beverages ?
(a) Penicillium notatum
(b) Saccharomyces cerevisiae
(c) Aspergilus niger
(d) Clostridium butylicum
Answer:
(b) Saccharomyces cerevisiae

Question 6.
Which of the following options contains the end products formed during anaerobic respiration in yeast ?
(a) H2O, CO2 and energy
(b) H2S, C6H12O6 and energy
(c) CO2, C2H5OH and energy
(d) H2O and CO2
Answer:
(c) CO2, C2H5OH and energy

Question 7.
The chemical substances produced by some microbes which can kill or retard the growth of other microbes are called
(a) antiseptics
(b) antacids
(c) antibiotics
(d) all of these
Answer:
(c) antibiotics

Question 8.
Antibiotics are obtained from
(a) bacteria
(b) fungi
(c) actinomycetes
(d) all of these
Answer:
(d) all of these

Question 9.
Which of the following antibiotics was extensively used to treat American soldiers wounded in World War 11 ?
(a) Neomycin
(b) Bacitracin
(c) Chloramphenicol
(d) Penicillin
Answer:
(d) Penicillin

Question 10.
Streptomycin is obtained from
(a) Streptomyces griseus
(b) S. cerevisiae
(c) S. venezuelae
(d) S. rimosus
Answer:
(a) Streptomyces griseus

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 11.
Enzyme which has the fibrinolytic effect is
(a) protease
(b) amylase
(c) lipase
(d) streptokinase
Answer:
(d) streptokinase

Question 12.
Statins used for lowering blood cholesterol level are extracted from
(a) algae
(b) bacteria
(c) viruses
(d) yeast
Answer:
(d) yeast

Question 13.
Monascus purpureus is a yeast commercially used in the production of
(a) citric acid
(b) ethanol
(c) blood cholesterol lowering statins
(d) streptokinase for removing clots from blood vessels
Answer:
(c) blood cholesterol lowering statins

Question 14
is the first step of sewage treatment.
(a) Precipitation
(b) Chlorination
(c) Sedimentation
(d) Aeration
Answer:
(c) Sedimentation

Question 15.
During the primary treatment of sewage, solid particles that settle down are called
(a) floes
(b) primary sludge
(c) activated sludge
(d) anaerobic sludge
Answer:
(b) primary sludge

Question 16.
The purpose of biological treatment of waste water is to
(a) reduce BOD
(b) increase BOD
(c) reduce sedimentation
(d) increase sedimentation
Answer:
(a) reduce BOD

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 17.
The masses of bacteria held together by slime and fungal filaments to form mesh-like structures are called as
(a) primary sludge
(b) floes
(c) activated sludge
(d) anaerobic sludge
Answer:
(b) floes

Question 18.
BOD is………..in polluted water and in potable water.
(a) more, less
(b) less, more
(c) less in both
(d) medium in both
Answer:
(a) more, less

Question 19.
In the sewage treatment, bacterial floes are allowed to sediment in a settling tank. This sediment is called as
(a) inactivated sludge
(b) activated sludge
(c) primary sludge
(d) secondary sluge
Answer:
(b) activated sludge

Question 20.
Which of the following steps is taken by the Ministry of Environment and Forests to protect rivers from water pollition ?
(a) Ganga Action Plan
(b) Narmada Action Plan
(c) Yamuna Action Plan
(d) Both (a) and (c)
Answer:
(d) Both (a) and (c)

Question 21.
Methanogens, growing anaerobically on cellulosic material produce
(a) methane
(b) methane and carbon dioxide
(c) methane and hydrogen
(d) methane, carbon dioxide and hydrogen
Answer:
(d) methane, carbon dioxide and hydrogen

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 22.
Which of the following bacteria is present in the rumen of cattle ?
(a) Azotobacter
(b) Rhizobium
(c) Methanobacterium
(d) Azospirillum
Answer:
(c) Methanobacterium

Question 23.
Process of biogas production is
(a) aerobic process
(b) anaerobic process
(c) active process
(d) passive process
Answer:
(b) anaerobic process

Question 24.
Biogas is produced by
(a) aerobic breakdown of biomass
(b) anaerobic breakdown of biomass
(c) with the help of methanogenic bacteria
(d) both (b) and (c)
Answer:
(d) both (b) and (c)

Question 25.
Dragonflies are used to get rid of
(a) mosquitoes
(b) aphids
(c) butterfly caterpillars
(d) both (a) and (b)
Answer:
(a) mosquitoes

Question 26.
A microbial biocontrol agent that can be used to control butterfly caterpillars is
(a) Trichoderma polysporum
(b) Bacillus thuringiensis
(c) Streptococcus
(d) mycorrhiza
Answer:
(b) Bacillus thuringiensis

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 27.
Bacillus thuringiensis is used to control
(a) bacterial pathogens
(b) fungal pathogens
(c) nematodes
(d) insect pests
Answer:
(d) insect pests

Question 28.
Bacillus thuringiensis (Bt) strains have been used for designing novel
(a) biofertilisers
(b) bio-metallurgical techniques
(c) bio-mineralisation process
(d) bio-insecticidal plants
Answer:
(d) bio-insecticidal plants

Question 29.
Trichoderma harzianum has proved to be a useful microorganism for
(a) gene transfer in higher plants
(b) biological control of soil-borne plant pathogens
(c) bioremediation of contaminated soils
(d) reclamation of wastelands
Answer:
(b) biological control of soil-borne plant pathogens

Question 30.
Baculoviruses (Nucleopolyhedrovirus) do not show
(a) host specificity
(b) narrow spectrum applications
(c) effects on non-target pathogens
(d) utility in IPM programme
Answer:
(c) effects on non-target pathogens

Question 31.
Integrated Pest Management (IPM) discourages the excessive used of
(a) biological methods
(b) chemical pesticides
(c) mechanical methods
(d) all of these
Answer:
(b) chemical pesticides

Question 32.
Which of the following is not used as a biopesticide ?
(a) Trichoderma harzianum
(b) Nucleopolyhedrovirus
(c) Xanthomonas campestris
(d) Bacillus thuringiensis
Answer:
(c) Xanthomonas campestris

Question 33.
Organic farming does not include
(a) green manures
(b) chemical fertilisers
(c) farmyard manures
(d) compost
Answer:
(b) chemical fertilisers

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 34.
Organic farming includes
(a) use of fertilisers and pesticides of biological origin
(b) IPM (Integrated Pest Management)
(c) locally developed pest resistant varieties
(d) all of these
Answer:
(d) all of these

Question 35.
Living organisms used to enrich the nutrient quality of the soil are called as
(a) biocontrol agents
(b) biofertilisers
(c) synthetic fertilisers
(d) natural fertilisers
Answer:
(d) natural fertilisers

Question 36.
Biofertilisers are
(a) some bacteria and cyanobacteria
(b) fertilisers formed by ploughing in barseem
(c) fertilisers obtained by decay of dead organisms
(d) fertilisers prepared by mixing cattle dung with crop residues
Answer:
(a) some bacteria and cyanobacteria

Question 37.
Biofertilisers are the living organisms which
(a) bring about soil nutrient enrichment
(b) maximise the ecological benefits
(c) minimise the environmental hazards
(d) all of these
Answer:
(d) all of these

Question 38.
Which one of the following can be used as biofertiliser in cotton field ?
(a) Azolla-Anabaena
(b) Streptococcus
(c) Azospirillum
(d) Azotobacter chroococcum
Answer:
(d) Azotobacter chroococcum

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 39.
The symbiotic association between fungi and roots of higher plants is referred to as
(a) lichen
(b) mycorrhiza
(c) biofertiliser
(d) biocontrol agent
Answer:
(b) mycorrhiza

Question 40.
Cyanobacteria are
(a) heterotrophs
(b) chemotrophs
(c) autotrophs
(d) organotrophs
Answer:
(c) autotrophs

Question 41.
A nitrogen fixing microbe associated with the fern Azolla in rice fields is
(a) Frankia
(b) Rhizobium
(c) Spirulina
(d) Anabaena
Answer:
(d) Anabaena

Question 42.
Azolla pinnata has been found to be an important biofertiliser for paddy crops. This quality is due to the presence of
(a) N2 fixing bacteria
(b) N2 fixing cyanobacteria
(c) mycorrhizae
(d) all of these
Answer:
(b) N2 fixing cyanobacteria

Question 43.
Which of the following is widely used as a successful biofertiliser in Indian rice field ?
(a) Rhizobium
(b) Acacia arabica
(c) Acalypha indica
(d) Azolla pinnata
Answer:
(d) Azolla pinnata

Question 44.
Which of the following options incldes biofertilscrs ?
(a) cowdung manure and farmyard waste
(b) A quick growing crop ploughed back into the field
(c) Nostoc, Oscillatoria
(d) All of these
Answer:
(c) Nostoc, Oscillatoria

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 45.
Which of the following is a non-symbiotic biofertiliser ?
(a) VAM
(b) Azotobacter
(c) Anabaena
(d) Rhizobium
Answer:
(b) Azotobacter

Question 46.
Nitrogen fixation in root nodules of Alnus is brought about by
(a) Frankia
(b) Azorhizobium
(c) Bradyrhizobium
(d) Clostridium
Answer:
(a) Frankia

Question 47.
The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is
(a) vitamin C
(b) vitamin D
(c) vitamin B12
(d) vitamin E
Answer:
(c) vitamin B12

Question 48.
Wastewater treatment generates a large quantity of sludge, which can be treated by
(a) anaerobic digesters
(b) floe
(c) chemicals
(d) oxidation pond
Answer:
(a) anaerobic digesters

Question 49.
Methanogenic bacteria are not found in
(a) rumen of cattle
(b) gobar gas plant
(c) bottom of water-logged paddy field
(d) activated sludge
Answer:
(d) activated sludge

Question 50.
The primary treatment of wastewater involves the removal of
(a) dissolved impurities
(b) stable particles
(c) toxic substances
(d) harmful bacteria
Answer:
(b) stable particles

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 51.
BOD of wastewater is estimated by measuring the amount of
(a) total organic matter
(b) biodegradable organic matter
(c) oxygen evolution
(d) oxygen consumption
Answer:
(d) oxygen consumption

Question 52.
Which one of the following alcoholic drinks is produced without distillation ?
(a) Wine
(b) Whisky
(c) Rum
(d) Brandy
Answer:
(a) Wine

Question 53.
The free-living fungus Trichoderma can be used for
(a) killing insects
(b) biological control of plant diseases
(c) controlling butterfly caterpillars
(d) producing antibiotics
Answer:
(b) biological control of plant diseases

Question 54.
Mycorrhiza does not help the host plant in
(a) enhancing its phosphorus uptake capacity
(b) increasing its tolerance to drought
(c) enhancing its resistance to root pathogens
(d) increasing its resistance to insects
Answer:
(d) increasing its resistance to insects

Question 55.
Which one of the following is not a nitrogen-fixing organism ?
(a) Anabaena
(b) Nostoc
(c) Azotobacter
(d) Pseudomonas
Answer:
(d) Pseudomonas

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Question 56.
The residue left after methane production from cattle dung is
(a) burnt
(b) burried in land fills
(c) used as manure
(d) used in civil construction
Answer:
(c) used as manure

Question 57.
Methanogens do not produce
(a) oxygen
(b) methane
(c) hydrogen sulphide
(d) carbon dioxide
Answer:
(a) oxygen

Bihar Board 12th Biology Objective Answers Chapter 10 Microbes in Human Welfare

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Bihar Board 12th Biology Objective Questions and Answers

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 1.
Which of the following is the “bird flu virus” ?
(a) H5N1
(b) Haemophilus influenzae
(c) HIV
(d) Rhino virus
Answer:
(a) H5N1

Question 2.
The infectious and contagious bacterial disease that affects cattle, buffaloes, horses, sheeps and goats is
(a) anthrax
(b) rinderpest
(c) tick fever
(d) necrosis
Answer:
(a) anthrax

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 3.
Which of the following is an improved variety of chicken ?
(a) Jersey
(b) Leghorn
(c) Himgiri
(d) Kalyan Sona
Answer:
(b) Leghorn

Question 4.
Which of the following is a draught breed of Indian cattle ?
(a) Malvi
(b) Gir
(c) Sahiwal
(d) Deoni
Answer:
(a) Malvi

Question 5.
Holstein-Frisian, Brown Swiss and Jersey are all well known
(a) exotic breeds of cow
(b) exotic breeds of goat
(c) exotic breeds of poultry
(d) animal husbandry scientists
Answer:
(a) exotic breeds of cow

Question 6.
Which one of the following is a breed of cattle ?
(a) Ayrshire
(b) Ghagus
(c) Kadaknath
(d) Scampi
Answer:
(a) Ayrshire

Question 7.
Which one of the following poultry birds is not an English breed ?
(a) Sussex
(b) Australorp
(c) Orpington
(d) Minorca
Answer:
(b) Australorp

Question 8.
High milk yielding cross bred Frieswal cow is the product of
(a) Brown Swiss × Sahiwal
(b) Friesian × Sahiwal
(c) Holstein × Tharparkar
(d) Brown Swiss × Red sindhi
Answer:
(b) Friesian × Sahiwal

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 9.
What strategy would you suggest if a person wants to evolve a pure line in an animal ?
(a) Cross-breeding
(b) Inbreeding
(c) Out-breeding
(d) artificia insemination
Answer:
(b) Inbreeding

Question 10.
Which of the following statements is not correct regarding inbreeding ?
(a) It is the breeding between animals of the same breed
(b) It decreases homozygosity
(c) It exposes harmful recessive genes
(d) It helps in accumulation os superior genes
Answer:
(b) It decreases homozygosity

Question 11.
The term “inbreeding depression” is related to
(a) increased fertility and productivity
(b) increased milk production
(c) reduced fertility & productivity
(d) reduced milk production
Answer:
(c) reduced fertility & productivity

Question 12.
Continued inbreeding, especially close inbreeding generally results in
(a) inbreeding depression
(b) inbreeding stimulation
(c) inbreeding hybridisation
(d) inbreeding mutation
Answer:
(a) inbreeding depression

Question 13.
The breeding carried out between animals of different breeds is called
(a) out-crossing
(b) cross-breeding
(c) inbreeding
(d) both (a) and (b)
Answer:
(b) cross-breeding

Question 14.
Which of the following is an example of a cross-breed ?
(a) Mule
(b) Hilsa
(c) Hisardale
(d) Sahiwal
Answer:
(c) Hisardale

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 15.
Hisardale is a new breed of sheep developed in Punjab by crossing
(a) Merino ram and Bikaneri ewe
(b) Assel ram and White leghorn ewe
(c) Rhode Island ram and White leghorn ewe
(d) Cochin ram and Ghagus ewe
Answer:
(a) Merino ram and Bikaneri ewe

Question 16.
Crossing of individuals of two different species to produce a hybrid is called
(a) interspecific hybridisation
(b) intervarietal hybridisation
(c) intergeneric hybridisation
(d) intravarietal hybrididisation
Answer:
(a) interspecific hybridisation

Question 17.
Artificial insemination involves
(a) super ovulation
(b) semen collection
(c) egg collection
(d) embryo collection
Answer:
(b) semen collection

Question 18.
Artificial breeding of cattle is brough about by
(a) artiticial insemination
(b) super ovulation and embryo transplantation
(c) MOET
(d) all of these
Answer:
(d) all of these

Question 19.
MOET stands for
(a) Multiple Ovulation and Egg transfer Technology
(b) Multiple Ovary and Embryo Transfer Technology
(c) Multiple Ovulation Embryo Transfer Technology
(d) Method of Egg Transfer Technology
Answer:
(c) Multiple Ovulation Embryo Transfer Technology

Question 20.
Multiple ovulation embryo transfer technology is related to
(a) transfer of super embryo
(b) transfer of super eggs
(c) super ovulation and embryo transfer
(d) both (a) and (b)
Answer:
(c) super ovulation and embryo transfer

Question 21.
‘Lean meat’ is cosidered to be of high quality because it has
(a) lesser but easily digestible protein
(b) lesser lipid content
(c) more fat that makes the meqt softer
(d) longer table life due to lesser chances of infection
Answer:
(b) lesser lipid content

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 22.
In livestock breeding experiments, which of the following stages is transferred to surrogate mothers ?
(a) Unfertilised eggs
(b) Fertilised eggs
(c) 8 to 32 celled embryo
(d) Frozen semen
Answer:
(c) 8 to 32 celled embryo

Question 23.
The term ‘apiculture’ refers to
(a) tissue culture
(b) pisciculture
(c) bee-keeping
(d) animal-keeping
Answer:
(c) bee-keeping

Question 24.
Which of the following plays a role in indigenous system of medicine ?
(a) Plant breeding
(b) Fisheries
(c) Apiculture
(d) MOET
Answer:
(c) Apiculture

Question 25.
In honey, the main constituent is
(a) calcium
(b) sugar
(c) protein
(d) water
Answer:
(b) sugar

Question 26.
Beewax is the secretion of badominal glands of
(a) drones
(b) worker bees
(c) queen bees
(d) works and queen bees
Answer:
(b) worker bees

Question 27.
Apis dorsata is
(a) little bee
(b) rock bee
(c) European bee
(d) Indian bee
Answer:
(b) rock bee

Question 28.
The use of honeybee is
(a) to help in pollination
(b) production of bees wax
(c) production of honey
(d) all of these
Answer:
(d) all of these

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 29.
Keeping beehives in crop fields during flowering period increases
(a) crop yield
(b) honey yield
(c) weeds yield
(d) both (a) and (b)
Answer:
(d) both (a) and (b)

Question 30.
Which of the following is not a freshwater fish ?
(a) Salmon
(b) Mrigal
(c) Catla
(d) Rohu
Answer:
(a) Salmon

Question 31.
Which of the following are common freshwater fishes ?
(a) Mackerel and rohu
(b) Rohu, common carp and Catla
(c) Hilsa and sardine
(d) None of these
Answer:
(b) Rohu, common carp and Catla

Question 32.
Which one of the following is a marine fish ?
(a) Rohu
(b) Hilsa
(c) Catla
(d) Common carp
Answer:
(b) Hilsa

Question 33.
Which one of the following is an exotic carp species ?
(a) Labeo rohita
(b) Crprinus carpio
(c) Labeo bata
(d) Cirrhinus mrigals
Answer:
(b) Crprinus carpio

Question 34.
Aquaculture is the rearing and management of
(a) molluscs and crustaceans
(b) only freshwater fishes
(c) economically useful aquatic plants and animals
(d) only aquatic plants
Answer:
(c) economically useful aquatic plants and animals

Question 35.
Aquaculture does not include
(a) prawns
(b) fishes
(c) silkworms
(d) shell fishery
Answer:
(c) silkworms

Question 36.
Which of the following is correctly matched ?
(a) Sericulture – Fish
(b) Aquaculture – Mosquito
(c) Apiculture – Honeybee
(d) Pisciculture – Silkmoth
Answer:
(c) Apiculture – Honeybee

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 37.
Germplasm collection is the collection of
(a) germ cells
(b) semens
(c) plants/seeds with all the diverse alleles for all genes
(d) egg cells
Answer:
(c) plants/seeds with all the diverse alleles for all genes

Question 38.
Major percentage of India’s Gross Domestic Product is constituted by
(a) industry
(b) agriculture
(c) export
(d) small scale cottage industry
Answer:
(b) agriculture

Question 39.
The Noble Laureate, who developed semi-dwarf wheat varieties in Mexioc was
(a) Norman E. Borlaug
(b) herbert Boyer
(c) William Harvey
(d) Typhoid Mary
Answer:
(a) Norman E. Borlaug

Question 40.
Jaya and Ratna are the semi-dwarf varieties of
(a) wheat
(b) rice
(c) cowpea
(d) mustard
Answer:
(b) rice

Question 41.
Turnip mosaic disease is caused by
(a) bacteria
(b) viruses
(c) nematodes
(d) fungi
Answer:
(b) viruses

Question 42.
Which of the following dieases is caused by virus ?
(a) Tobacco mosaic
(b) Late blight of potato
(c) Turnip mosaic
(d) Both (a) and (c)
Answer:
(d) Both (a) and (c)

Question 43.
Which of the following is incorrectly matched ?
Disease Causative organism
(a) Black rot of crucifers Bacteria
(b) Brown rust of wheat Fungi
(c) Late blight of potato Virus
(d) Red rot of sugarcane Fungi
Answer:
(c) Late blight of potato Virus

Question 44.
Which of the following dieases is caused by bacteria ?
(a) Tobacco mosaic
(b) Black rot of crucifers
(c) Red rot of sugarcane
(d) Lata blight of potato
Answer:
(b) Black rot of crucifers

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 45.
Black rust of wheat is caused by
(a) Puccinia
(b) Albugo
(c) Ustilagp
(d) Cystopus
Answer:
(a) Puccinia

Question 46.
Which of the following is incorrectly paired ?
(a) What – Himgiri
(b) Milch breed – Sahiwal
(c) Rice – Ratna
(d) Pusa Komal – Brassica
Answer:
(d) Pusa Komal – Brassica

Question 47.
Yellow mosaic virus resistant variety “Parbhani Kranti” belongs to
(a) bhindi
(b) barley
(c) chilli
(d) cauliflower
Answer:
(a) bhindi

Question 48.
Hairy leaves of many plants are asociated with
(a) resistance to insect pests
(b) resistance to viruses
(c) resistance to fungi
(d) resistance to bacteria
Answer:
(a) resistance to insect pests

Question 49.
Resistance to jassids in cotton plants and to cereal leaf beetle in wheat plants is due to
(a) biochemical characters
(b) physiological characters
(c) morphological characters
(d) none of these
Answer:
(c) morphological characters

Question 50.
Maize generates resistance against stem borers by having
(a) low aspartic acid, high nitrogen and sugar content
(b) low aspartic acid and sugar but high nitrogen content
(c) high aspartic acid and nitrogen but low sugar content
(d) high aspartic acid, low nitrogen and sugar content
Answer:
(d) high aspartic acid, low nitrogen and sugar content

Question 51.
Biofortification refers to the development of crop plants which are
(a) resistant to disease
(b) resistant to insect pests
(c) having improved nutritional quality
(d) having improved iron content
Answer:
(c) having improved nutritional quality

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 52.
A wheat variety, Atlas 66, which has been used as a donor for improving cultivated wheat is rich in
(a) iron
(b) carbohydrates
(c) proteins
(d) vitamins
Answer:
(c) proteins

Question 53.
Shakti, Ratten and Protina (varieties of maize) are rich in
(a) lysine
(b) glycine
(c) fats
(d) carbohydrates
Answer:
(a) lysine

Question 54.
Which of the following can be used for cultivation of SCP ?
(a) Animal manure
(b) Straw
(c) Molasses
(d) All of these
Answer:
(d) All of these

Question 55.
250 g of Methylophilus methy lotrophus can be expected
to produce tonnes of proteins.
(a) 15
(b) 25
(c) 40
(d) 50
Answer:
(b) 25

Question 56.
Single cell protein can be obtained from
(a) bacteria
(b) algae
(c) fungi
(d) all of these
Answer:
(d) all of these

Question 57.
Which of the following should be used as an explant to generate a disease free plant ?
(a) Anther
(b) Ovary cell
(c) Shoot tip
(d) Young embryo
Answer:
(c) Shoot tip

Question 58.
Hormone responsible for growth of the root in micropropagation is
(a) auxin
(b) gibberellin
(c) cytokinin
(d) abscisic acid
Answer:
(b) gibberellin

Question 59.
somaclones are
(a) somatic hybrids
(b) genetically identical to the original plant
(c) used to recover disease free plants
(d) sterile plants
Answer:
(d) sterile plants

Question 60.
Meristem culture is used
(a) to produce disease free plants
(b) in germplasm conservation
(c) in rapid clonal multiplication
(d) all of these
Answer:
(d) all of these

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 61.
Meristem culture is the cultue of
(a) axillary or apical shoot meristems
(b) anthers
(c) plant seeds
(d) young embryos
Answer:
(a) axillary or apical shoot meristems

Question 62.
A plant cell without cell wall is called
(a) proplast
(b) protoplast
(c) nucleoplasm
(d) explant
Answer:
(b) protoplast

Question 63.
A somatic hybird between potato and tomato is named as
(a) bomato
(b) mopato
(c) pomato
(d) topamo
Answer:
(c) pomato

Question 64.
The enzymes required to obtain protoplast from a plant cell are
(a) cellulase
(b) chitinase
(c) pectinase
(d) both (a) and (c)
Answer:
(d) both (a) and (c)

Question 65.
The chances of contracting bird flu from a properly cooked (above 100°C) chicken and egg are
(a) very high
(b) high
(c) moderate
(d) none
Answer:
(d) none

Question 66.
A group of animals which are related by descent and share many similarities are referred to as
(a) breed
(b) race
(c) variety
(d) species
Answer:
(a) breed

Question 67.
Inbreeding is carried out in animal husbandry because it
(a) increases vigour
(b) improves the breed
(c) increases heterozygosity
(d) increases homozygosity
Answer:
(d) increases homozygosity

Question 68.
Sonalikea and Kalyan Sona are varieties of
(a) wheat
(b) rice
(c) millet
(d) tobacco
Answer:
(a) wheat

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 69.
Which one of the following is not a fungal disease ?
(a) Rust of wheat
(b) Smut of Bajra
(c) Black rot of crucifers
(d) Red rot of sugarcane
Answer:
(c) Black rot of crucifers

Question 70.
Fungicides and antibiotics are chemicals that
(a) enhance yield and disease resistance
(b) kill pathogenic fungi and bacteria, respectively
(c) kill all pathogenic microbes
(d) kill pathogenic bacteria and fungi respectively
Answer:
(b) kill pathogenic fungi and bacteria, respectively

Question 71.
Use of certain chemicals and radiation to change the base sequences of genes of crop plants is termed
(a) recombinant DNA technology
(b) transgenic mechanism
(c) mutation breeding
(d) gene therapy
Answer:
(c) mutation breeding

Question 72.
The scientific process by which crop plants are enriched with certain desirable nutrients is called
(a) crop protection
(b) breeding
(c) bio-fortification
(d) bio-remediation
Answer:
(c) bio-fortification

Question 73.
The term ‘totipotency’ refers to the capacity of a
(a) cell to generate whole plant
(b) bud to generate whole plant
(c) seed to germinate
(d) cell to enlarge in size
Answer:
(a) cell to generate whole plant

Question 74.
An explant is
(a) dead plant
(b) part of the plant
(c) part of the plant used in tissue culture
(d) part of the plant that expresses a specific gene
Answer:
(c) part of the plant used in tissue culture

Question 75.
The biggest constraint of plant breeding is
(a) availability of desirable gene in the crop and its wild relatives
(b) infrastructure
(c) trained manpower
(d) transfer of genes from unrelated sources
Answer:
(a) availability of desirable gene in the crop and its wild relatives

Question 76.
Lysine and tryptophan are
(a) proteins
(b) non-essential amino acids
(c) essential amino acids
(d) aromatic amino acids
Answer:
(c) essential amino acids

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 77.
Micropropagation is
(a) propagation oif microbes in vitro
(b) propagation of plants in vitro
(c) propagation of cells in vitro
(d) growing plants on smaller scale
Answer:
(b) propagation of plants in vitro

Question 78.
Protoplast is
(a) another name for protoplasm
(b) an animal cell
(c) a plant cell without a cell wall
(d) a plant cell
Answer:
(c) a plant cell without a cell wall

Question 79.
To isolate protoplast, one needs
(a) pectiriase
(b) cellulase
(c) both pectinase and cellulase
(d) chitinase
Answer:
(c) both pectinase and cellulase

Question 80.
Which one of the following is a marine fish ?
(a) Rohu
(b) Hilsa
(c) Catla
(d) Common Carp
Answer:
(b) Hilsa

Question 81.
Which one of the following products of apiculture is used in cosmetics and polishes ?
(a) Honey
(b) Oil
(c) Wax
(d) Royal jelly
Answer:
(c) Wax

Question 82.
More than 70 percent of livestock population is in
(a) Denmark
(b) India
(c) China
(d) India and China
Answer:
(d) India and China

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Question 83.
The agriculture sector of India employs about
(a) 50 percent of the population
(b) 70 percent of the population
(c) 30 percent of the population
(d) 60 percent of the population
Answer:
(d) 60 percent of the population

Question 84.
33 percent of India’s (Gross Domestic Product) comes from
(a) industry
(b) agriculture
(c) export
(d) small-scale cottage industries
Answer:
(b) agriculture

Question 85.
A collection of all the alleles of all the genes of a crop plant is called
(a) germplasm collection
(b) protoplasm collection
(c) herbarium
(d) somaclonal collection
Answer:
(a) germplasm collection

Bihar Board 12th Biology Objective Answers Chapter 9 Strategies for Enhancement in Food Production

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Bihar Board 12th Chemistry Objective Questions and Answers

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 1.
Copper sulphate dissolves in ammonia due to the formation of
(a) Cu2O
(b) [Cu(NH3)4]SO4
(c) [Cu(NH3)4]OH
(d) [Cu(H2O)4]SO4
Answer:
(b) [Cu(NH3)4]SO4

Question 2.
The number of ions given by [Pt(NH3)6]Cl4 inaqueous solution will be
(a) two
(b) three
(c) five
(d) eleven
Answer:
(c) five

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 3.
When one mole of each of the following complexes is treated with excess of AgNO3, which will give maximum amount of AgCl ?
(a) [Co(NH3)6]Cl3
(b)[Co(NH3)5CI]Cl2
(c) [Co(NH3)4Cl2]Cl
(d) [Co(NH3)3Cl3]
Answer:
(a) [Co(NH3)6]Cl3

Question 4.
According to Werner’s theory of coordination compounds.
(a) primary valency is ionisable
(b) secondary valency is ionisable
(c) primary and secondary valencies are ionisable
(d) neither primary nor secondary valency is ionisable
Answer:
(a) primary valency is ionisable

Question 5.
Which of the following primary and secondary valencies are not correctly marked against the compounds ?
(a) [Cr(NH3)6]Cl3, p = 3,s = 6
(b) K2[Pt(Cl4], p = 2, s = 4
(c) [Pt(NH3)2CI2], p = 2, s = 4
(d) [Cu(NH3)4]SO4 , p = 4, s = 4
Answer:
(d) [Cu(NH3)4]SO4 , p = 4, s = 4

Question 6.
The ligand N(CH2CH2NH2)3 is
(a) bidentate
(b) tridentate
(c) tetradentate
(d) pentadentate
Answer:
(c) tetradentate

Question 7.
Which of the following is a tridentate ligand ?
(a)EDTA4-
(b) (COO)2
(c) dien
(d) NO2
Answer:
(c) dien

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 8.
Among the following, which are ambidentate ligands ?
(i)SCN
(ii) NO
(iii) NO;
(iv) C2O4
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)
Answer:
(a) (i) and (iii)

Question 9.
Which of the following ligands form a chelate ?
(a) Acetate
(b) Oxalate
(c) Cyanide
(d) Ammonia
Answer:
(b) Oxalate

Question 10.
Which of the following is not a neutral ligand ?
(a) H2O
(b) NH3
(c) ONO
(d) CO
Answer:
(c) ONO

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 11.
Which of the following ligands will not show chelation ?
(a) EDTA
(b) DMG
(c) Ethane – 1, 2-diamine
(d) SCN
Answer:
(d) SCN

Question 12.
The coordination number and the oxidation state of the  element E in the complex [E(en)2(C2O4)]NO2 (where (en) is ethylenediamine) are, respectively
(a) 6 and 3
(b) 6 and 2
(c) 4 and 2
(d) 4 and 3
Answer:
(a) 6 and 3

Question 13.
The correct IUPAC name of the coordination compound K3[Fe(CN)5NO] is
(a) potassium pentacyanonitrosylferrate (II)
(b) potassium pentacyanonitroferrate(III)
(c) potassium nitritopentacyanoeferrate (IV)
(d) potassium nitritepentacyanoiron (II)
Answer:
(a) potassium pentacyanonitrosylferrate (II)

Question 14.
Correct formula of tetraamminechloronitroplatinum (IV) sulphate can be written as
(a) [ Pt(NH3 )4 (ONO)Cl ]SO4
(b) [Pt(NH3)4Cl2NO2]2SO4
(c) [Pt(NH3)4(NO2)Cl]SO4
(d) [PtCl (ONO) NH3(SO4)]
Answer:
(c) [Pt(NH3)4(NO2)Cl]SO4

Question 15.
Which among the following will be named as dibromidobis (ethylenediamine) chromium (III) bromide ?
(a) [Cr(en)2Br2]Br
(b) [Cr(en)Br]
(c) [Cr(en)Br2]Br
(d) [Cr(en)3]Br3
Answer:
(a) [Cr(en)2Br2]Br

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 16.
The name of the compound [Co(NH3)5NO2]Cl2 will be
(a) pentaamminonitrocobalt (II) chloride
(b) pentaamminenitrochloridecobaltate (III)
(c) pentaamminenitrocobalt (III) chloride
(d) pentanitrosoamminechlorocobaltate (III)
Answer:
(c) pentaamminenitrocobalt (III) chloride

Question 17.
How many geometrical isomers are there for [Co(NH3)2Cl4] (octahedral) and [AuCl2Br2] (square planar) ?
(a) Two cis and trans, no geometrical isomers
(b) Two cis and trans, two cis and trans
(c) No geometrical isomers, two cis and trans
(d) No geometrical isomers, no geometrical isomers
Answer:
(b) Two cis and trans, two cis and trans

Question 18.
Which of the following will not show geometrical isomerism ?
(a) [Cr(NH3)4Cl2]Cl
(b) [Co(en)2Cl2]CI
(c) [Co(NH3)5NO2]Cl2
(d) [Pt(NH3)2Cl2]
Answer:
(c) [Co(NH3)5NO2]Cl2

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 19.
Which of the following shows maximum number of isomers ?
(a) [Co(NH3)4Cl2]
(b) [Ni(en)(NH3)4]2+
(c) [Ni(C2O4)(en)2]2-
(d) [Cr(SCN)2(NH3)4]+
Answer:
(d) [Cr(SCN)2(NH3)4]+

Question 20.
Which of the following complexes exists as pair of enantiomers ?
(a) [Co(NH3)4Cl2]+
(b) [Cr(en)3]3+
(c) [Co(P(C2H5)3)2ClBr]
(d) trans- [Co(en)2Cl2 ]+
Answer:
(b) [Cr(en)3]3+

Question 21.
Two isomers of a compound Co(NH3)3Cl3(MA3B3type) are shown in the figures.
Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds 1
The isomers can be classified as
(a) (i) fac-isomers (ii) mer-isomer
(b) (i) optical-isomer (ii) trans-isomer
(c) (i) mer-isomer (ii) fac-isomer
(d) (i) trans-isomer (ii) cis-isomer
Answer:
(a) (i) fac-isomers (ii) mer-isomer

Question 22.
Which of the following compounds exhibits linkage isomerism ?
(a) [Co(en)3]Cl3
(b) [Co(NH3)6][Cr(en)3]
(c) [Co(en)2 (NO2)Cl]Br
(d) [Co(NH3)5Cl]Br2
Answer:
(c) [Co(en)2 (NO2)Cl]Br

Question 23.
[Pt(NH3)4][CuCl4] and tCu(NH3)4][PtCl4] are known is
(a) ionisation isomers
(b) coordination isomers
(c) linkage isomers
(d) polymerisation isomers
Answer:
(b) coordination isomers

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 24.
Which of the following isomers will give white precipitate with BaCl2 solution ?
(a) [Co(NH3)5SO4]Br
(b) [Co(NH3)5 Br]SO4
(c) [Co(NH3)4(SO4)2]Br
(d) [Co(NH3)4 Br(SO4)]
Answer:
(b) [Co(NH3)5 Br]SO4

Question 25.
CrCl3.6H2O exists in different isomeric forms which show different colours like violet and green. This is due to
(a) ionisation isomerism
(b) coordination isomerism
(c) optical isomerism
(d) hydrate isomerism
Answer:
(d) hydrate isomerism

Question 26.
The hybridisation involved in [Co(C2O4)3]3- is
(a) sp3d2
(b) sp3d3
(c) dsp3
(d) d2sp3
Answer:
(d) d2sp3

Question 27.
Which of the following complexes will have tetrahedral shape ?
(a) [PdCl4]2-
(b) [Pd(CN)4]2-
(c) [Ni(CN)4l2-
(d) [NiCl4]2-
Answer:
(d) [NiCl4]2-

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 28.
The complex ion which has no d-electrons in the central metal atom is
(a) [MnO4]
(b) [Co(NH3)6]3+
(c) [Fe(CN)6]3-
(d) [Cr(H2O)6]+
Answer:
(a) [MnO4]

Question 29.
The lowest value paramagnetism is shown by
(a) [Co(CN)6]3-
(b) [Fe(CN)6]3-
(c) [Cr(CN)6]3-
(d) [Mn(CN)6]3-
Answer:
(a) [Co(CN)6]3-

Question 30.
[CoF6]3- is
(a) paramagnetic and undergoes sp3d2 hybridisation
(b) diamagnetic and undergoes d2sp3 hybridisation
(c) paramagnetic and undergoes sp3d hybridisation
(d) diamagnetic and undergoes sp3 hybridisation
Answer:
(a) paramagnetic and undergoes sp3d2 hybridisation

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 31.
The magnitude of magnetic moment (spin only) of [NiCl4]2- will be
(a) 2.82B.M.
(b) 3.25B.M.
(c) 1.23 B.M.
(d) 5.64 B.M.
Answer:
(a) 2.82B.M.

Question 32.
Which of the following has largest paramagnetism ?
(a) [Cr(H2O)6]3+
(b) [Fe(H2O)6]2+
(c) [Cu(H2O)6]2+
(d) [Zn(H2O)2]2+
Answer:
(b) [Fe(H2O)6]2+

Question 33.
Which of the following descriptions about [FeCl6 ]4- is correct about the complex ion ?
(a) sp3 d, inner orbital complex, diamagnetic
(b) sp3 d2, outer orbital complex, paramagnetic
(c) d2sp3, inner orbital complex, paramagnetic
(d) d2sp3, outer orbital complex, diamagnetic
Answer:
(b) sp3 d2, outer orbital complex, paramagnetic

Question 34.
When excess of ammonia is added to copper sulphate solution, the deep blue coloured complex is formed. The complex is
(a) tetrahedral and paramagnetic
(b) tetrahedral and diamagnetic
(c) square planar and diamagnetic
(d) square planar and paramagnetic
Answer:
(d) square planar and paramagnetic

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 35.
Among the following compounds which is both paramagnetic and coloured ?
(a) K2Cr2O7
(b) [Co(SO4)]
(c) (NH4)2[TiCl6]
(d) K3[Cu(CN)4]
Answer:
(b) [Co(SO4)]

Question 36.
The spin only magnetic moment value of Cr(CO)6 is
(a) 2.84 B.M.
(b) 4.90 B.M.
(c) 5.92 B.M.
(d) O.B.M.
Answer:
(d) O.B.M.

Question 37.
Which of the following complexes will show maximum paramagnetism ?
(a) 3d4
(b) 3d5
(c) 3d6
(d) 3d7
Answer:
(b) 3d5

Question 38.
Electronic configuration of [Cu(NH3)6]2+ on the basis of crystal field splitting theory is
Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds 2
Answer:
(b)

Question 39.
Which of the following shall form an octahedral complex ?
(a) d4 (low spin)
(b) d8 (high spin)
(c) d6 (low spin)
(d) None of these
Answer:
(c) d6 (low spin)

Question 40.
The value of the ‘spin only’ magnetic moment for one of the following configuration is 2.84 BM. The correct one is
(a) d4(in strong ligand field)
(b) d4 (in weak ligand field)
(c) d3 (in weak as well as in strong fields)
(d) d5 (in strong ligand field)
Answer:
(a) d4(in strong ligand field)

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 41.
CuSO4.5H2O is blue in colour while CuSO4 is colourless due to
(a) presence of strong field ligand in CuSO4.5H2O
(b) due to absence of water (ligand), d-d transitions are not possible in CuSO4
(c) anhydrous CuSO4 undergoes d-d transitions due to crystal field splitting
(d) colour is lost due to loss of unpaired electrons
Answer:
(b) due to absence of water (ligand), d-d transitions are not possible in CuSO4

Question 42.
[Fe(CN)6]4- and [Fe(H2O)6]2+ show different colours in dilute solution because
(a) CN is a strong field ligand and H2O is a weak field ligand hence magnitude of CFSE is different
(b) both CN and H2O absorb same wavelength of energy
(c) complexes of weak field ligands are generally colourless
(d) the sizes of CN and H2O are different hence their colours are also different
Answer:
(d) the sizes of CN and H2O are different hence their colours are also different

Question 43.
The terminal and bridged CO ligands in the compound [Co2(CO)8] are respectively
(a) 0, 2
(b) 6, 1
(c) 5,2
(d) 6, 2
Answer:
(b) 6, 1

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 44.
The geometry possessed by [Ni(CO)4] is
(a) tetrahedral
(b) square planar
(c) linear
(d) octahedral
Answer:
(a) tetrahedral

Question 45.
Cr-C bond in the compound [Cr(CO)6] shows 71- character due to
(a) covalent bonding
(b) coordinate bonding
(c) synergic bonding
(d) ionic bonding
Answer:
(c) synergic bonding

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 46.
The overall complex dissociation equilibrium constant for the complex [Cu(NH3)4]2+ ion will be (P4 for this complex is 2.1 x 1013)
(a) 7 x 10-14
(b) 2.1 x 1013
(c) 11.9 x 10-2
(d) 2.1 x 103
Answer:
(a) 7 x 10-14

Question 47.
Mark the incorrect match
(a) Insulin – Zinc
(b) Haemoglobin – Iron
(c) Vitamin Bp –  Cobalt
(d) Chlorophyll – Chromium
Answer:
(d) Chlorophyll – Chromium

Question 48.
The correct IUPAC name of [Pt(NH3)2Cl2] is ……………….
(a) diamminedichloridoplatinum (II)
(b) diamminedichloridoplatinum (IV)
(c) diamminedichloridoplatinum (0)
(d) dichloridodiammineplatinum (IV)
Answer:
(a) diamminedichloridoplatinum (II)

Question 49.
The stabilisation of coordination compounds due to chelation is called the chelate effect. Which of the following is the most stable complex species ?
(a) [Fe(CO)5]
(b) [Fe(CN)6]-
(c) [Fe(C2O4)3]3-
(d) [Fe(H2O)6]3+
Answer:
(c) [Fe(C2O4)3]3-

Question 50.
Indicate the complex ion which shows geometrical isomerism.
(a) [Cr(H2O)4Cl2]+
(b) [Pt(NH3)3Cl]
(c) [Co(NH3)6]3+
(d) [Co(CN)5(NC)]3-
Answer:
(a) [Cr(H2O)4Cl2]+

Bihar Board 12th Chemistry Objective Answers Chapter 9 Coordination Compounds

Question 51.
The CFSE for octa hedral [CoCl6]4- is 18,000 cm-1. The CFSE for tetrahedral [CoCl4 ]2 will be
(a) 18,0000 cm-1
(b) 16,000 cm-1
(c) 8,000 cm-1
(d) 20,000 cm-1
Answer:
(c) 8,000 cm-1

Question 52.
The compounds [Co(SO4)(NH3)s] Br and [Co(SO4)(NH3)5]Cl represent
(a) linkage isomerism
(b) ionisation isomerism
(c) coordination isomerism
(d) no isomerism
Answer:
(d) no isomerism

Question 53.
A chelating agent has two or more than two donor atoms to bind to a single metal ion. Which of the following is not a chelating agent ?
(a) Thiosulphato
(b) Oxalato
(c) Glycinato
(d) Ethane-1. 2-diamine
Answer:
(a) Thiosulphato

Question 54.
Which of the following species is not expected to be a ligand ?
(a) NO
(b) NH4
(c) NH2CH2CH2NH2
(d) CO
Answer:
(b) NH4

 

 

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Bihar Board 12th Biology Objective Questions and Answers

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 1.
Who is the father of genetic engineering ?
(a) Steward Linn
(b) Stanley Cohen
(c) Paul Berg
(d) Kary Mullis
Answer:
(c) Paul Berg

Question 2.
Plasmid used to construct the first recombinant DNA was isolated from which bacterium species ?
(a) Escherichia coli
(b) Salmonelia typhimurium
(c) Agrobacterium tumefaciens
(d) Thermus aquaticus
Answer:
(b) Salmonelia typhimurium

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 3.
The term ‘molecular scissors’ refers to
(a) recombinant DNA
(b) restriction enzymes
(c) Taq polymerase
(d) palindromic nucleotide sequences.
Answer:
(b) restriction enzymes

Question 4.
The term ’chemical knife’ refers to
(a) polymerases
(b) endonucleases
(c) ribonucleases
(d) cellulases.
Answer:
(b) endonucleases

Question 5.
One of the key factors, which makes the plasmid the vector in genetic engineering is
(a) its resistance to antibiotics
(b) its resistance to restriction enzymes
(c) its ability to carry a foreign gene
(d) its ability to cause infection in the host.
Answer:
(c) its ability to carry a foreign gene

Question 6.
The term ’recombinant DNA’ refers to
(a) DNA of the host cell
(b) DNA with a piece of foreign DNA
(c) DNA with selectable marker
(d) DNA with more than one recognition sites.
Answer:
(b) DNA with a piece of foreign DNA

Question 7.
The term ’chimeric DNA’ refers to
(a) DNA with overhanging stretches
(b) DNA with palindromic sequence
(c) a recombinant DNA
(d) molecular scissors.
Answer:
(c) a recombinant DNA

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 8.
Which of the following is not a tool of genetic engineering ?
(a) Cloning vector
(b) Restriction enzyme
(c) Foreign DNA
(d) GMO
Answer:
(d) GMO

Question 9.
The first restriction endonuclease isolated was
(a) EcoRI
(b) BamHI
(c) Sail
(d) Hindll
Answer:
(d) Hindll

Question 10.
The letter ’R’ in EcoRI is derived from
(a) the name of genus
(b) the name of strain
(c) the name of species
(d) the term ‘restriction1.
Answer:
(b) the name of strain

Question 11.
The source of the restriction enzyme Hindlll is
(a) Escherichia coli RY 13
(b) Haemophilus influenzae Rd
(c) Bacillus amyloliquefaciens H
(d) Streptomyces albus.
Answer:
(d) Streptomyces albus.

Question 12.
The sticky ends of a fragmented DNA molecule are made of
(a) calcium salts
(b) endonuclease enzyme
(c) unpaired bases
(d) methyl groups.
Answer:
(c) unpaired bases

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 13.
Identify the palindromic sequence in the following.
(a) \(\frac{\text { GAATTC }}{\text { CTTUUG }}\)
(b) \(\frac{\mathrm{GGATCC}}{\mathrm{CCTAGG}}\)
(C) \(\frac{\mathrm{GGATCC}}{\mathrm{CCTAGG}}\)
(d) \(\frac{\text { GGATA }}{\text { GCTAA }}\)
Answer:
(b) \(\frac{\mathrm{GGATCC}}{\mathrm{CCTAGG}}\)

Question 14.
Which of the following statements is not correct regarding EcoRI restriction endonuclease enzyme ?
(a) It is isolated from Escherichia coli RY 13.
(b) Its recognition sequence is 5′-GAATTC-3′ 3′- CTTAAG-5′.
(c) It produces complementary blunt ends.
(d) None of these
Answer:
(c) It produces complementary blunt ends.

Question 15.
If a plasmid vector is digested with EcoRI at a single site, then
(a) one sticky end will be produced
(b) two sticky ends will be produced
(c) four sticky ends will be produced
(d) six sticky ends will be produced.
Answer:
(b) two sticky ends will be produced

Question 16.
Which of the following tools of recombinant DNA technology is incorrectly paired with its use ?
(a) EcoRI – Production of sticky ends
(b) DNA ligase – Multiplication of rDNA molecules
(c) ori – copy number
(d) Selectable marker – Identification of transformants
Answer:
(b) DNA ligase – Multiplication of rDNA molecules

Question Question 17.
Which one of the following characteristic is generally not preferred for a cloning vector ?
(a) An origin of replication
(b) An antibiotic resistance marker
(c) Multiple restriction sites
(d) A high copy number
Answer:
(c) Multiple restriction sites

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 18.
Which of the following is not a cloning vector ?
(a) Cosmid
(b) pBR322
(c) Sail
(d) Phagemid
Answer:
(c) Sail

Question 19.
pBR322 was the first artificial cloning vector to be constructed. What does “BR” stands for ?
(a) Bacteriophage and Recombinant
(b) Boliver and Rodriguez
(c) Boyer and Replicative
(d) None of these
Answer:
(b) Boliver and Rodriguez

Question 20.
ce gene (tetR) has recognition site for which of the following res
In pBR322, tetracycline resistantriction endonuclease ?
(a) Hind III
(b) BamHI
(c) EcoRI
(d) PstI
Answer:
(d) PstI

Question 21.
What will be the effect if pBR322, a cloning vector does not carry ‘ori’ site ?
(a) Sticky ends will not produce
(b) Transformation will not takes place.
(c) The cell will transform into a tumour cell.
(d) Replication will not takes place.
Answer:
(d) Replication will not takes place.

Question 22.
An advantage of using yeasts rather than bacteria as recipient cells for the recombinant DNA of eukaryotes is that yeasts can
(a) produce restriction enzymes
(b) excise introns from the RNA transcript
(c) remove methyl groups
(d) reproduce more rapidly.
Answer:
(b) excise introns from the RNA transcript

Question 23.
Which of the following bacteria is used as a vector for plant genetic engineering ?
(a) Agrobacterium tumefacines
(b) Bacteriophages
(c) Thermus aquaticus
(d) Pyrococcus furiosus
Answer:
(a) Agrobacterium tumefacines

Question 24.
a crown gall bacterium, is called as ‘natural genetic engineer’ of plants.
(a) Escherichia coli
(b) Streptomyces albus
(c) Agrobacterium tumefaciens
(d) Azotobacter
Answer:
(c) Agrobacterium tumefaciens

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 25.
The term “competent” refers to
(a) increasing the competition between cells
(b) making cells impermeable for DNA
(c) Increasing the efficiency with which DNA enters the bacterium through pores in its cell wall
(d) making cells permeable for divalent cations.
Answer:
(c) Increasing the efficiency with which DNA enters the bacterium through pores in its cell wall

Question 26.
Micro-injection is a method used to
(a) produce sticky ends of DNA
(b) provide protection against pathogen
(c) purify the DNA
(d) inject recombinant DNA into the nucleus of an animal cell.
Answer:
(d) inject recombinant DNA into the nucleus of an animal cell.

Question 27.
Which of the following is required for micro-injection method of gene transfer ?
(a) Micro-particles
(b) Micro-pipettes
(c) Divalent cations
(d) UV radiations
Answer:
(b) Micro-pipettes

Question 28.
In biolistic method of gene transfer, the microparticles coated with foreign DNA are bombarded into target cells at a very high velocity. These microparticles are made up of
(a) silver or tungsten
(b) arsenic or silver
(c) gold or tungsten
(d) none of these.
Answer:
(c) gold or tungsten

Question 29.
During isolation of genetic material, the chemical used to precipitate out the purified DNA is
(a) bromophenol blue
(b) Chilled ethanol
(c) ethidium bromide
(d) both (a) and (c).
Answer:
(b) Chilled ethanol

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 30.
The polymerase chain reaction is a technique used for
(a) amplification of DNA
(b) amplification of enzymes
(c) amplification of proteins
(d) all of these.
Answer:
(a) amplification of DNA

Question 31.
Process used for amplification or multiplication of DNA in DNA fingerprinting is
(a) polymerase chain reaction
(b) southern blotting
(c) northern blotting
(d) none of these.
Answer:
(a) polymerase chain reaction

Question 32.
Enzyme ‘Taq polymerase’ used in PCR, has been isolated from bacterium
(a) Agrobacterium tumefaciens
(b) Thermus aquaticus
(c) Streptomyces albus
(d) Escherichia coli
Answer:
(b) Thermus aquaticus

Question 33.
Which one of the following is not a correct match ?
(a) Tumour inducing – Ti plasmid
(b) DNA probe – Identifies the desired DNA
(c) PCR – DNA staining
(d) Agarose – Seaweeds
Answer:
(c) PCR – DNA staining

Question 34.
The correct sequence of different steps of polymerase chain reaction is
(a) annealing → denaturation → extension
(b) denaturation → extension → annealing
(c) denaturation → annealing → extension
(d) extension → denaturation → annealing.
Answer:
(c) denaturation → annealing → extension

Question 35.
Which of the following is required to perform polymerase chain reaction ?
(a) Primers, dNTPs and DNA polymerase
(b) DNA, CaCl2 and nuclease
(c) Mg + 2, DNA
(d) Both (a) and (c)
Answer:
(d) Both (a) and (c)

Question 36.
Which of the following is not used to transfer the recombinant DNA into the host ?
(a) Micro-injection method
(b) Gene gun method
(c) Bioreactors
(d) Disarmed pathogen vectors
Answer:
(c) Bioreactors

Question 37.
A device in which large volume of living cells are
cultured in order to get a specific product is called
(a) PCR
(b) agitator
(c) bioreactor
(d) assimilator.
Answer:
(c) bioreactor

Question 38.
Rising of dough is due to
(a) multiplication of yeast
(b) production of CO2
(c) emulsification
(d) hydrolysis of wheat flour starch into sugars.
Answer:
(b) production of CO2

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 39.
An enzyme catalysing the removal of nucleotides from the ends of DNA is
(a) endonuclease
(b) exonuclease
(c) DNA ligase
(d) Hind II.
Answer:
(b) exonuclease

Question 40.
The transfer of genetic material from one bacterium to another through the mediation of a vector like virus is termed as
(a) transduction
(b) conjugation
(c) transformation
(d) translation.
Answer:
(a) transduction

Question 41.
Which of the following is not required in the preparation of a recombinant DNA molecule ?
(a) Restriction endonuclease
(b) DNA ligase
(c) DNA fragments
(d) E. coli
Answer:
(d) E. coli

Question 42.
In agarose gel electrophoresis, DNA molecules are
separated on the basis of their
(a) charge only
(b) size only
(c) charge to size ratio
(d) all of the above.
Answer:
(b) size only

Question 43.
While isolating DNA from bacteria, which of the following enzymes is not used ?
(a) Lysozyme
(b) Ribonuclease
(c) Deoxyribonuclease
(d) Protease
Answer:
(c) Deoxyribonuclease

Question 44.
Which of the following has popularised the PCR (polymerase chain reactions) ?
(a) Easy availability of DNA template
(b) Availability of synthetic primers
(c) Availability of cheap deoxyribonucleotides
(d) Availability of ‘thermostable’ DNA polymerase
Answer:
(d) Availability of ‘thermostable’ DNA polymerase

Question 45.
An antibiotic resistance gene in a vector usually helps in the selection of
(a) competent cells
(b) transformed cells
(c) recombinant cells
(d) none of the above.
Answer:
(b) transformed cells

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Question 46.
Significance of ‘heat shock’ method in bacterial transformation is to facilitate
(a) binding of DNA to the cell wall
(b) uptake of DNA through membrane transport proteins
(c) uptake of DNA through transient pores in the bacterial cell wall
(d) expression of antibiotic resistance gene.
Answer:
(c) uptake of DNA through transient pores in the bacterial cell wall

Question 47.
Which of the following is not a source of restriction endonuclease ?
(a) Haemophilus influenzae
(b) Escherichia coli
(c) Entamoeba coli
(d) Bacillus amyloliquifaciens
Answer:
(c) Entamoeba coli

Question 48.
Which of the following steps are catalysed by Taq polymerase in a PCR reaction ?
(a) Denaturation of template DNA
(b) Annealing of primers to template DNA
(c) Extension of primer end on the template DNA
(d) All of the above
Answer:
(c) Extension of primer end on the template DNA

Question 49.
Who among the following was awarded the Nobel Prize for the development of PCR technique ?
(a) Herbert Boyer
(b) Hargovind Khurana
(c) Kary Mullis
(d) Arthur Komberg
Answer:
(c) Kary Mullis

Question 50.
Which of the following statements does not hold true for restriction enzyme ?
(a) It recognises a palindromic nucleotide sequence.
(b) It is an endonuclease.
(c) It is isolated from viruses.
(d) It produces the same kind of sticky ends in different DNA molecules.
Answer:
(c) It is isolated from viruses.

Bihar Board 12th Biology Objective Answers Chapter 11 Biotechnology: Principles and Processes

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Bihar Board 12th Maths Model Papers

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Time : 3 Hours 15 Min
Full Marks: 100

Instructions for the candidates :

  1. Candidates are required to give their answers in their own words as far as practicable.
  2. Figure in the right-hand margin indicates full marks.
  3. While answering the questions, the candidate should adhere to the word limit as far as practicable.
  4. 15 Minutes of extra time has been allotted for the candidate to read the questions carefully.
  5. This question paper is divided into two sections. Section-A and Section-B
  6. In Section A, there are 1-50 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with blue/black ball pen against the correct option on the OMR Sheet provided to you. Do not use Whitener/Liquid/ Blade/Nail on OMR Sheet otherwise result will be invalid.
  7. In section-B, there are 25 short answer type questions (each carrying 2 marks), out of which only 15 (fifteen) questions are to be answered.
    A part from this there is 08 Long Answer Type questions (each carrying 5 marks), out of which 4 questions are to be answered.
  8. Use of any electronic device is prohibited.

Objective Type Questions

There are 1 to 50 objective type questions with 4 options, choose the correct option which is to be answered on OMR Sheet (50 × 1 = 50)

Question 1.
What type of relation on the set A = {1,2,3,4} given by R = {(1,3), (4,2), (2,4), (2,3), (3,1)} is
(a) Reflexive
(b) Transitive
(c) Symmetric
(d) None of these
Answer:
(d) None of these

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 2.
If the operation * defined as (a * b) = a2 + b2 then the value of (3 * 4) * 5 is
(a) 650
(b) 125
(c) 625
(d) 3125
Answer:
(a) 650

Question 3.
If f: R → R defined as f(x) = 3x. Then the function is
(a) one-one into
(b) one-one onto
(c) Manyone into
(d) Many one onto
Answer:
(b) one-one onto

Question 4.
\(\tan ^{-1} \frac{2 x}{1-x^{2}}=\)
(a) 2sin-1x
(b) sin-12x
(c) tan-12x
(d) 2tan-1x
Answer:
(d) 2tan-1x

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 5.
The value of \(\cos ^{-1}\left(-\frac{1}{2}\right)\) is
(a) \(\frac{\pi}{3}\)
(b) \(\frac{\pi}{6}\)
(c) \(\frac{2 \pi}{3}\)
(d) \(\frac{3 \pi}{4}\)
Answer:
(c) \(\frac{2 \pi}{3}\)

Question 6.
tan-1x + cot-1x = :
(a) π
(b) \(\frac{\pi}{2}\)
(c) \(\frac{2 \pi}{3}\)
(d) \(\frac{3 \pi}{4}\)
Answer:
(b) \(\frac{\pi}{2}\)

Question 7.
\(\left[\begin{array}{ccc}
b c & 1 & 1 / a \\
c a & 1 & 1 / b \\
a b & 1 & 1 / c
\end{array}\right]=?\)
(a) 1/abc
(b) 0
(c) abc
(d) None of these
Answer:
(b) 0

Question 8.
\(\left|\begin{array}{cc}
\cos 15^{\circ} & \sin 15^{\circ} \\
\sin 75^{\circ} & \cos 75^{\circ}
\end{array}\right|=?\)
(a) 1
(b) π/2
(c) 0
(d) None of these
Answer:
(c) 0

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 9.
If λ ∈ R and ∆ = \(\left|\begin{array}{ll}
\mathbf{a} & \mathbf{b} \\
\mathbf{c} & \mathbf{d}
\end{array}\right|\)
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 1
Answer:
(c) \(\left|\begin{array}{ll}
\lambda a & \lambda b \\
\lambda c & \lambda d
\end{array}\right|\)

Question 10.
If A = \(\left[\begin{array}{lll}
1 & 2 & 3 \\
4 & 5 & 6
\end{array}\right]\) Then which of following is A’
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 2
Answer:
(c) \(\left[\begin{array}{ll}
1 & 4 \\
2 & 5 \\
3 & 6
\end{array}\right]\)

Question 11.
If y = sin (log x) then \(\frac{\mathrm{dy}}{\mathrm{dx}}=?\)
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 3
Answer:
\(\frac{\cos (\log x)}{x}\)

Question 12.
If y = x3 + 4x + 6 then \(\frac{d^{2} \cdot y}{d x^{2}}=?\)
(a) 3x3 + 4
(b) 3x2
(c) 6x
(d) 3x
Answer:
(c) 6x

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 13.
If y = log√x then the value of \(\frac{d y}{d x}\) is
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 4
Answer:
(a) \(\frac{1}{2 x}\)

Question 14.
If y = sin2x then the value of \(\frac{d^{2} y}{d x^{2}}\) is
(a) 2 sin 4x
(b) -4 sin 2x
(c) 4 sin 2A
(d) 4 cos2 2x
Answer:
(b) -4 sin 2x

Question 15.
The ratio of rate of change x2 and log x is
(a) 2x
(b) 2x2
(c) 2
(d) 2/3
Answer:
(b) 2x2

Question 16.
If \(y=\sec ^{-1}\left[\frac{\sqrt{x}+1}{\sqrt{x}-1}\right]+\sin ^{-1}\left[\frac{\sqrt{x}-1}{\sqrt{x}+1}\right]\) then \(\frac{d y}{d x}\) = :
(a) 1
(b) π
(c) π/2
(d) 0
Answer:
(d) 0

Question 17.
The vectors a1î + a2 ĵ + a3k̂ and b1î + b2 ĵ + b3 ĵ perpendicular to each other if
(a) \(\frac{a_{1}}{b_{1}}=\frac{a_{2}}{b_{2}}=\frac{a_{3}}{a_{3}}\)
(b) a1b1 + a2b2 + a3b3
(c) a1b2 + b2a1 + a3b2 = 0
(d) None of these
Answer:
(b) a1b1 + a2b2 + a3b3
Question 18.
k̂ × k̂ =
(a) 0
(b) 1
(c) |k|2
(d) None of these
Answer:
(a) 0

Question 19.
The scalar product of the vectors 5î + yĵ – 3k̂ and 3î – 4ĵ + 7k̂is
(a) 10
(b) -10
(c) 15
(d) -15
Answer:
(b) -10

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 20.
The vector equation of the line which passes through the points A(3,4, -7) and B(l, -1,6) is
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 5
Answer:
(a) \(\vec{r}=(3 \hat{i}+4 \hat{j}-7 \hat{k})+\lambda(\hat{i}-\hat{j}+6 \hat{k})\)

Question 21.
For what value of x, î + ĵ + k̂ is a unit vector ?
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 6
Answer:
(b) \(\frac{1}{\sqrt{3}}\)

Question 22.
Distance between the planes r̂. n̂ = p1 and r̂. n̂ = p2 is
(a) p1 – p2
(b) |p1-p2|
(c) \(\frac{\left|p_{1}-p_{1}\right|}{2}\)
(d) None of these
Answer:
b) |p1-p2|

Question 23.
\(\int_{0}^{2 / 3} \frac{d x}{4+9 x^{2}}\) is equal to
(a) \(\frac{\pi}{6}\)
(b) \(\frac{\pi}{12}\)
(c) \(\frac{\pi}{24}\)
(d) \(\frac{\pi}{4}\)
Answer:
(c) \(\frac{\pi}{24}\)

Question 24.
\(\int_{0}^{\pi / 2} \frac{\sin x}{\sin x+\cos x} d x\) dx is equal to
(a) \(\frac{\pi}{2}\)
(b) \(\frac{\pi}{4}\)
(c) π
(d) None of these
Answer:
(b) \(\frac{\pi}{4}\)

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 25.
\(\int x^{2} e^{x^{3}} d x=\)
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 7
Answer:
(a) \(\frac{1}{3} e^{x^{3}}+C\)

Question 26.
The value of \(\int_{0}^{\pi / 4} \sin 2 x d x\) is
(a) 1
(b) 1/2
(c) 1/3
(d) 1/4
Answer:
(b) 1/2

Question 27.
Area lying in the first quadrant and bounded by the circle x2 + y2 = 4 and x = 0, x = 2 is
(a) π
(b) \(\frac{\pi}{2}\)
(c) \(\frac{\pi}{3}\)
(d) \(\frac{\pi}{4}\)
Answer:
(a) π

Question 28.
The order of differentied equation
\(\left(\frac{d^{2} y}{d x^{2}}\right)+2\left(\frac{d y}{d x}\right)^{3}+9 y=0\) is
(a) 2
(b) 3
(c) 4
(d) None of these
Answer:
(a) 2

Question 29.
The differential equation of the family of straight line which passes through the origin is
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 8
Answer:
(b) \(y \frac{d y}{d x}=x\)

Question 30.
The solution of \(\frac{d y}{d x}\) = 1 + x + y + xy is
(a) x – y = k(1 + xy)
(b) log(1 + y)=x + \(\frac{x^{2}}{2}\) + k
(c) log (1 + x) = y + \(\frac{y^{2}}{2}\) + k
(d) None of these
Answer:
(b) log(1 + y)=x + \(\frac{x^{2}}{2}\) + k

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 31.
If \(\vec{a}=2 \vec{i}-5 \vec{\jmath}+\vec{k}\) and \(\vec{b}=4 \vec{i}+2 \vec{\jmath}+\vec{k}\) then \(\vec{a} \cdot \vec{b}=:\)
(a) 0
(b) -1
(c) 1
(d) 2
Answer:
(b) -1

Question 32.
If \(2 \vec{i}+\vec{j}+\vec{k}, 6 \vec{i}-\vec{j}+2 \vec{k}\) and \(14 \vec{i}-5 \vec{\jmath}+4 \vec{k}\) are the position vectors of the point A, B, C respectively, then
(a) A, B, C are collinear
(b) A, B, C are non-collinear
(c) \(\overrightarrow{A B} \perp \overrightarrow{B C}\)
(d) None of these
Answer:
(a) A, B, C are collinear

Question 33.
If \(|\vec{a} \times \vec{b}|=|\vec{a} \cdot \vec{b}|\) then angle between \(\vec{a}\) and \(\vec{b}\) is n
(a) 0
(b) \(\frac{\pi}{2}\)
(c) \(\frac{\pi}{4}\)
(d) π
Answer:
(c) \(\frac{\pi}{4}\)

Question 34.
Angle between the vectors 2î + 3ĵ + 2k̂ and î + 4ĵ + 5k̂ is
(a) 30°
(b) 90°
(c) 45°
(d) 60°
Answer:
(b) 90°

Question 35.
l, m, n and l1 m1 n1 are the direction cosines of two lines are perpendicular to each other if:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 9
Answer:
(c) ll1 + mm1 + nn1 = 0

Question 36.
A straight line passes through (2, -1,3) and its direction ratio’s are 3, -1,2. Then the equation of the line is
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 10
Answer:
(b) \(\frac{x-2}{3}=\frac{y+1}{-1}=\frac{z-3}{2}\)

Question 37.
The direction ratio’s of the normal to the plane 7x + 4y – 2z + 5 = 0 is
(a) (7,4,5)
(b) (7,4,-2)
(c) (7,4,2)
(d) (0,0,0)
Answer:
(b) (7,4,-2)

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 38.
Angle between the lines \(\vec{r}=(4 \hat{i}-\hat{j})+s(2 \hat{i}+\hat{j}-3 k)\) and
\(\vec{r}=(\hat{i}-\hat{j}+2 \hat{k})+t(\hat{i}-3 \hat{j}+2 \hat{k})[latex] is
3n n 2n n
(a) [latex]\frac{3 \pi}{2}\)
(b) \(\frac{\pi}{3}\)
(c) \(\frac{2 \pi}{3}\)
(d) \(\frac{\pi}{6}\)
Answer:
(b) \(\frac{\pi}{3}\)

Question 39.
The vectors î + ĵ and ĵ + k̂ are perpendicular then unit vectors is equal to
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 11
Answer:
(c) \(\begin{aligned}
&\wedge \wedge \quad \wedge\\
&\frac{i+j+k}{3}
\end{aligned}\)

Question 40.
Which of the following is value of constant c of Rolle’s theorem when fix) = 2x3 – 5x2 – 4x + 3, x ∈\(\left[\frac{1}{3}, 3\right]\)
(a) \(-\frac{1}{3}\)
(b) \(\frac{2}{3}\)
(c) -2
(d) 2
Answer:
(d) 2

Question 41.
The modulus of the vector \(2 \vec{i}-7 \vec{j}-3 \vec{k}\) is
(a) √61
(b) √62
(c) √64
(d) √32
Answer:
(b) √62

Question 42.
The projection of the vector î – 2ĵ + k̂ on 2î – ĵ + k̂ is
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 12
Answer:
(b) \(\frac{5}{\sqrt{6}}\)

Question 43.
If \(|\vec{a}|=\sqrt{26}|\vec{b}|=7\) and \(|\vec{a} \times \vec{b}|=35\) then \(\vec{a} \cdot \vec{b}=\)
(a) 8
(b) 7
(c) 9
(d) 12
Answer:
(b) 7

Question 44.
The function Z = ax + by in Linear programming problem is called
(a) objective Function
(b) constraints
(c) Feasible solution
(d) corner point
Answer:
(a) objective Function

Question 45.
If P(A) = \(\frac{1}{2}\) ,P(B) = 0 then P\(\frac{A}{B}\) is
(a) 0
(b) 1/2
(c) 1
(d) Not defined
Answer:
(d) Not defined

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 46.
If P( A) = 0.8, P(B) = 0.5 and P(B/A) = 0.4 then P(A∪B) equal to :
(a) 0.78
(b) 0.88
(c) 0.98
(d) 1.08
Answer:
(c) 0.98

Question 47.
Two events A and B are mutually independent if
(a) P(A’ B’) = [1 – P(A)][1 – P(B)]
(b) P(A) = P(B)
(c) P(A) + P(B) = 1
(d) A and B are muttually exclusive
Answer:
(a) P(A’ B’) = [1 – P(A)][1 – P(B)]

Question 48.
The probability of getting doublet with one die is
(a) \(\frac{2}{3}\)
(b) \(\frac{1}{6}\)
(c) \(\frac{5}{6}\)
(d) \(\frac{5}{36}\)
Answer:
(b) \(\frac{1}{6}\)

Question 49.
If A and B are two events such that if P(A∪B) = P(a) Then
(a) P(A/B)= 1
(b) P(B/A)= 1
(c) P(A/B) = 0
(d) P(A/B) = 0
Answer:
(d) P(A/B) = 0

Question 50.
If A and B are imitualy exclusive events, then
(a) P (A/B) = 0
(b) P (B/A) = 0
(c) P(A∪B) = 0
(d) P (A ∩ B) = 0
Answer:
(d) P (A ∩ B) = 0

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Non-Objective Type Questions

Short Answer Type Questions

Q. No. 1 to 25 are of Short Answer type carry of 2 marks each. Answer any 15 questions. (15 × 2 = 30)

Question 1.
Let a function f: R→R defined as \(f(x)=\frac{x^{2}}{x^{2}+1}\) ∀ x ∈ R . Then find f-1.
Answer:
Let f: R→R \( defined as f(x)=\frac{x^{2}}{x^{2}+1}\)
Taking 1, 1, ∈ R, we get, Clearly f(1) = f(-1) = 1/2
So, f is manyone function. Thus f-1 is not exists.

Question 2.
If \(\tan ^{-1}\left(\frac{1-x}{1+x}\right)=\frac{1}{2} \tan ^{-1} x\) , then find x.
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 13

Question 3.
Applying properties of determinant, prove that:
\(\left|\begin{array}{lll}
1 & 1 & 1 \\
a & b & c \\
b c & c a & a b
\end{array}\right|=(a-b)(b-c)(c-a)\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 14
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 15

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 4.
If \(\left[\begin{array}{cc}
a-b & 2 a+c \\
2 a-b & 3 c+a
\end{array}\right]=\left[\begin{array}{cc}
-1 & 5 \\
0 & 13
\end{array}\right]\) then find a,b,c and d
Answer:
\(\left[\begin{array}{cc}
a-b & 2 a+c \\
2 a-b & 3 c+a
\end{array}\right]=\left[\begin{array}{cc}
-1 & 5 \\
0 & 13
\end{array}\right]\)
a – b = -1 …………(1)
2a – b = 0 …………(2)
2a + c = 5…….(3)
3c + d = 13……(4)
Subtract (1) from (2), we get
2a – b – a + b = 0 + 1 ⇒ a = 1
Frorn (2), 2a – b = 0 ⇒ 2.1 – b ⇒ b = 2
Putting the value ofa in(3), we get 2a + c = 5 ⇒ 2.1 +c = 5
⇒ c = 5 – 2=3 , Lastly putting the value of c in (4), we get
3c + d = 13 ⇒ 3 x 3 + d = 13 ⇒ d= 13 – 9 = 4
Thus a= 1,b=2,c=3and d=4

Question 5.
If y = ex(sin x + cos x) then prove that
\(\frac{d^{2} y}{d x^{2}}-2 \frac{d y}{d x}+2 y=0\) we have
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 16

Question 6.
Verify the continuity at x = 0 of the function \(f(x)=\left\{\begin{aligned}
\frac{|\sin x|}{x}, & x \neq 0 \\
1, & x=0
\end{aligned}\right.\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 17

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 7.
Differentiate: sec {tan ( √x)} with respect to x.
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 18

Question 8.
Find the projection of the vector î + ĵ + k̂) in the direction ĵ
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 19

Question 9.
Show that the tangents to the curve y = 7x3 +11 at the points where x = 2 and x= 2 are parallel.
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 20

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 10.
Integrate: \(\int \frac{(\log x)^{2}}{x} d x\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 21

Question 11.
Find the value of \(\int_{0}^{\pi / 4} \tan ^{2} x d x\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 22

Question 12.
Solve the differential equation \(\frac{d y}{d x}\) = 1 + x + y + xy
Answer:
We have, \(\frac{d y}{d x}\) = (1 + x) + y(1 + x) = (1 + x)(1 + y)
\(\int \frac{d y}{1+y}\) = (1 + x)dx = ∫dx + ∫ xdx
log(1 + y) = x + \(\frac{x^{2}}{2}+c\)

Question 13.
Form the differential equation of the family of circles toucingthey-axis at Origin
Answer:
The equation of circle of radius a and centre (a, 0) and which passes through the origin with y-axis is
(x – a)2 + y2 = a2
or x2 + y2 = 2ax …(1)
Differentiating w.r.t. x, we get
2x + 2yy’= 2a
or, x + yy’ = a ……(2)
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 23
Putting the value of a from (2) in (1), we get
x2 + y2 = 2x(x + yy’) = 2x2 + 2 xy y’
or \(2 x y \frac{d y}{d x}+x^{2}-y^{2}=0\)
Which is the required differential equation

Question 14.
Show that the lines \(\vec{r}=(\hat{i}+\hat{j}-\hat{k})+\lambda(3 \hat{i}-\hat{j})\) and
\(\vec{r}=(4 \hat{i}-\hat{k})+\mu(2 \hat{i}+3 \hat{k})\) intersect each other. Find their point of intersection.
Answer:
Since the lines intersects for the any value of λ and μ the refore the value of \(\vec{r}\) is equal for them
Then (î + ĵ – k̂) + λ(3î – ĵ) =(4î – k̂) + µ(2î+3k)
⇒ (î + 3λ)î+(1 – λ)ĵ – k̂= (4 + 2µ)î + (3µ – 1)k̂)
⇒ 1 + 3λ = 4 + 2µ, 1 – λ = 0 and 3µ – 1 = -1
⇒ 3λ – 2µ = 3 …………(1)
λ = 1 ………….. (2)
and µ = 0 …(3)
clearly, λ = 1 and µ = O are sastis fled
Putting λ = 1. we get r̂ = (î + ĵ – k̂) + λ(3î – ĵ)
r̂ = (4î + 0ĵ – k̂)
Thus point of intersection of line is (4, 0, -1)

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 15.
Find the equation of the through the point (5, -2, 4) and which is parallell to (2î – ĵ + 3k̂)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 24
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 25
Question 16.
What is the maximum value of the function sin x + cos x
Answer:
Let the interval be [0, 2π] is given
Then f(x) = sin A’ + cos x
f'(x) = cos x – sin x
For maximum and minimum value,f'(A) = 0
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 26

Question 17.
Prove that : \(\overrightarrow{(\vec{a}-\vec{b})} \times(\vec{a}+\vec{b})=2(\vec{a} \times \vec{b})\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 27

Question 18.
Solve : \(\frac{d y}{d x}+2 y \tan x=\sin x, y=0\) when x = π/3
Answer:
We have \(\frac{d y}{d x}\) + 2ytan x = sin x
This is linear differential equation, where P = 2tanx and Q = sin.x
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 28

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 19.
If A and B are independent events, then prove that A and B’ are independent events.
Answer:
Given, A and B are independent then
P(A∩B) = P(A).P(B)
Now, A = (A∩B) ∪ (A∩B’)
⇒ P(A) = P(A∩B) + P(A∩B’)
P(A) = P(A).P(B) +P(A∩B’)
⇒ P(A∩B’) = P(A)-P(A) P(B)
⇒ P(A∩B’) = P(A) [ 1 -P(B) ]
⇒ P(A∩B’)= P(A).P(B’)
Thus A and B’ are independent.

Question 20.
If \(|\overrightarrow{\mathbf{a}}+\overrightarrow{\mathbf{b}}|=|\overrightarrow{\mathbf{a}}-\overrightarrow{\mathbf{b}}|\) the prove that \(\overrightarrow{\mathbf{a}} \perp \overrightarrow{\mathbf{b}}\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 29

Question 21.
Solve the differential equation \(\frac{d y}{d x}\)= 1 – x + y – xy
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 30

Question 22.
If P(A) = 0.8, P(B) = 0.5 and P(B/A) =0.4, then find
P(A ∩ B)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 31

Question 23.
Show that the relation R in the set Z of integers given by R = {(a, b): 3 divides a – b} is an equivalence relation.
Answer:
Let a,b,c ∈ Z
(i) (a, a) ∈ R ⇒ aRa ⇒ a – a = O ∈ Z, divisible by 3 since 0∈Z, which is divisible by 3, so R is reflexive relation.
(ii) (a, b) ∈ R ⇒ (b, a) ∈ R ⇒ (a – b) is divisible by ⇒ (b – a) is divisible by 3. Since (a – b) is divisible by 3 so (b- a) is also divisible by 3, ∀ a, b ∈ Z. so R is symmetric relation.
(iii) (a, b) ∈ R, (b, c) ∈ R ⇒ (a, c) ∈ R ⇒ (a – b) is divisible by 3, (b – c) is divisible by 3
⇒ a – b + b – c = (a – c) is divisible by 3.
Since (a – b) is divisible by 3, (b – c) is divisible by 3
⇒ (a – c) is divisible by 3, ∀ a, b, c ∈ Z. SO R is transitive relation.
Since R is reflexsive, symmetric and transitive relations. Therefore R is an equivalence relation.

Question 24.
Solve tan-12x + tan -13x = π/4
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 32
or, 5x = 1 – 6x2
or, 6x2+ 5x – 1 = 0
or, 6x2 + 6x – x – 1 = 0
or, 6x (x + 1) – 1(x+ 1) = 0 – or,
(6x- 1)(x+ 1) = 0
∴ 6x – 1 = 0
or x + 1 = 0
i.e, x = 1/6 or, x = -1
Since x ≠ -1 so x = 1/6

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 25.
Find X and Y if X + Y = \(\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 33

Long Answer Type Questions

Questions No. 26 to 33 are Long Answer Type Questions. Each question carry 5 marks. Answer any 4 question. (4 × 5 = 20)

Question 26.
Show that semi-vertical angle of right circular cone of given surface are anf maximum value is sin -1(1/3)
Answer:
Let r be the radius, Z be sland height and h be height of the cone. Then s = πr2 + πrl
or \(l=\frac{s-\pi r^{2}}{\pi r}\)
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 34
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 35
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 36

Question 27.
Prove that the function sinx(1 + cosx),x ∈ [0,π] is maximum at x = \(\frac{\pi}{3}\)
Answer:
Let f(x) = sinx(1 + cosx)
⇒ f'(x) = -sin x + cosx(1 + cosx)
⇒ f'(x) = 2cos2x + cosx – 1 = (2cosx – 1)(cosx + 1)
and f”(x) = -4cosx sin x – sin x
= -sinx(1 + 4cosx)
Now f'(x) = 0 ⇒ (2cosx – 1)(cosx + 1) = 0
⇒ 2cos x = 1 or, cos x = – 1
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 37

Question 28.
Find the area of the parabola’s enclosed by the region y2 = 4ax and x2 = 4ay, where a
Answer:
Given parabola’s y2 = 4ax …(1)
and x2 = 4ay …(2)
On solving (1) and (2), we get point of intersection So, substituting the value of x from (1) in (2), we get
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 38
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 39

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 29.
Find the value at \(\int_{0}^{\pi / 4} \log (1+\tan x) d x\)
Answer:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 40

Question 30.
Find the vector equation of plane which pases through the points A(3, -5, -1); B(-1, 5,7) and parallel to the
vector 3î – ĵ + 7k̂
Answer:
Let the position vector of given points A and B are (3î – 5ĵ – k̂) and -î + 5ĵ + 7k̂
Let P be any point on the plane with position vector x
xî + yĵ + zk̂
AP=(x — 3)î + (y + 5)ĵ + (z +1)k̂
and AB = -4î + 10ĵ+ 8k̂
Clearly AP, AB and 3î – ĵ + 7k̂ are coplanar . So the equation of plane is
\(\left|\begin{array}{ccc}
x-3 & y+5 & z+1 \\
-4 & 10 & 8 \\
3 & -1 & 7
\end{array}\right|=0\)
⇒(x – 3) (70 + 8) – (y + 5)(-28 – 24) + (z +1)(4 – 30)= 0
⇒ 78 (x-3) + 52(y + 5)-26(z + l) = 0
⇒ 78x – 234 + 52y + 260 – 26z – 26 = 0
⇒ 78x + 52y-26z = 0
⇒ 3x + 2y-z = 0
The vector equation of plane is r. (3î – 5ĵ – k̂) = 0

Question 31.
Prove that the lines \(\frac{x+3}{-3}=\frac{y-1}{1}=\frac{z-5}{5}\) are \(\frac{x+1}{-1}=\frac{y-2}{2}=\frac{z-5}{5}\) coplanar.
Answer:
Here x1 = -3, y1 = 1, z1 = 5, a1 = -3, b1 = 1, c1 =5
and x2 = -1 y2= 2, z2 = 5,a2 = -1 b2 = 2, c2 = 5
Given lines are copalanar if
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 41
=2(5 – 10) – 1 (-15 + 5) + 0(-6 + 1)
= 2 x (-5) + 10 + 0 = 0
Hence the given lines are coplanar.

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 32.
Using LPP method, maximize Z = 10x + 6y subject to
constraints 3x +y ≤ 12,2x + 5y ≤ 34, x ≥ 0,y ≥ 0.
Answer:
Maximize objeftive function Z = 10x + 6y
Subject to constraints
3x + y≤ 12 ⇒ 3x + y = 12 -..(1)
2x + 5y ≤ 34 ⇒ 2x + 5y = 34 …(2)
x ≥ 0, y ≥ 0 ⇒ x = 0,y = 0 …(3)
First of all draw graph of equations (1) to (3) corTes ponds to the inequations, we see from figure, the feasible, region OAPD be form, which is bounded also.
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 42
The co-ordinate of the comer point of the feasible region, are 0(0, 0), A(4, 0), P(2, 6) and D(0, 34/5). Lastly, by using comer point method to find the maximum value of Z are as follows :
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 43
It is obvious from the above table that maximum value of Z is 56 at the point (2,6). Thus the maximum value of Z is 56.

Bihar Board 12th Maths Model Question Paper 4 in English Medium

Question 33.
A manufacturer produces nuts and bolts. It takes 1 hour of work on machine A and 3 hours on machine B to produce a package of nuts. It takes 3 hours on machine A and 1 hour on machine B to produce a package of bolts. He earns a profit of Rs. 17.50 per packages on nuts and Rs. 7.00 per package on bolts. How many package of each should be produced each day so as to maximise his profit, if he operates his machines for at the most 12 hours a day ?
Answer:
Let x nuts and y bolts are produced. We have the given data, as follows:
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 44
Now, the time of machine A is used. = (x + 3y) hours Avilable time = 12 hours,
So, x + 3y ≤ 12 ⇒ x + 3y = 12 …(1)
The time of machine B is used = (3x + y) hours
Available time = 12 hours, So 3x + y ≤ 12
⇒ 3x + y = 12 …. (2)
Profit function Z = 17.5x + 7y is objective function
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 45
Also, non-negative constraints
x ≥ 0, y ≥ 0 ⇒ x = 0, y = 0 …(3)
Now, linear equation (1) corresponds to inequation passes through the points A( 12, 0) and B(0, 4)
Putting x = 0, y = 0 in x + 3y ≤ 12,
we get 0 ≤ 12, which is true
So x + 3y ≤ 12 lies on and below AB The linear equation (2) corresponds to inequation passes through C(4, 0) and D(0. 12)
Putting x = 0, v = 0 in 3x + y ≤ 12,
we get 0 ≤ 12 which is true
So, 3x + y ≤ 12 lies on and below CD.
x ≥ 0 is the region which lies on and to the right on y-axis
y ≥ 0 is the region which lies on and above the x-axis
The line AB and CD intersects at the point P(3,3) Clearly it is obvious from figure the region OCPB is feasible region and is bounded. Lastly, calculate the value of Z= 17.5x + 7y as follows.
Bihar Board 12th Maths Model Question Paper 4 in English Medium - 46
From above table, it is clear that the maximum profit is Rs. 73.50 when 3 nuts and 3 bolts packages are produced.

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Bihar Board 12th Chemistry Objective Questions and Answers

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 1.
Which of the following is less than zero during adsorption ?
(a) ΔG
(b) ΔS
(c) ΔH
(d) All of these
Answer:
(d) All of these

Question 2.
Which of the following is a property of physisorption ?
(a) High specificity
(b) Irreversibility
(c) Non-specificity
(d) None of these
Answer:
(c) Non-specificity

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 3.
Which of the following statement is not correct about physisorption ?
(a) It is a reversible process
(b) It requires less heat of adsorption
(c) It requires activation energy
(d) It takes place at low temperature
Answer:
(c) It requires activation energy

Question 4.
The incorrect statement about physical adsorption is
(a) it lacks specificity
(b) it is generally reversible
(c) porous surfaces are good adsorbent
(d) heat of adsorption is quite high
Answer:
(d) heat of adsorption is quite high

Question 5.
Which is correct in case of van der Waals adsorptions ?
(a) High temperature, low pressure
(b) High temperature, high pressure
(c) Low temperature, low pressure
(d) Low temperature, high pressure
Answer:
(d) Low temperature, high pressure

Question 6.
Which, of the following gases is least absorbed on charcoal ?
(a)HCl
(b) NH3
(c) O2
(d) CO2
Answer:
(c) O2

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 7.
Which of the following is not characteristic of chemisorption ?
(a) Adsorption is specific
(b) Heat of adsorption is of the order of 200 kJ mol-1
(c) Adsorption is irreversible
(d) Adsorption may be multimolecular layers
Answer:
(d) Adsorption may be multimolecular layers

Question 8.
Which of the following is not correct regarding the adsorption of a gas on the surface of solid ?
(a) On increasing pressure, adsorption keeps on increasing
(b) Enthalpy and entropy changes are negative
(c) Chemisorption is more specific than physisorption
(d) It is a reversible reaction
Answer:
(a) On increasing pressure, adsorption keeps on increasing

Question 9.
Which of the plots is adsorption isobar for chemisorption?
Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry 1
Answer:
(b)

Question 10.
Which of the following graphs would yield a stright line ?
(a) x/m vs p
(b) log x/m vs p
(c) x/m vs log p
(d) log x/m vs log p
Answer:
(d) log x/m vs log p

Question 11.
At low pressure, the fraction of the surface covered follows
(a) zero-order kinetics
(b) first order kinetics
(c) second order kinetics
(d) fractional  order kinetics
Answer:
(b) first order kinetics

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 12.
Which of the following gases present in a polluted area will be adsorbed most easily on the charcoal gas mask ?
(a) H2
(b) O3
(c) N2
(d) SO2
Answer:
(d) SO2

Question 13.
Which of the following is application of adsorption in chemical analysis
(a) Adsorption indicators
(b) Thin layer chromatography
(c) Qualitative analysis
(d) All of these
Answer:
(d) All of these

Question 14.
What is the role of adsorption in froth floatation process used especially for concentration of sulphide ores ?
(a) Shape selective catalysts
(b) Adsorption of pine oil on sulphide ore particles
(c) Adsorption of pine oil on impurities
(d) Production of heat in the process of exothermic reaction
Answer:
(b) Adsorption of pine oil on sulphide ore particles

Question 15.
Which of the following can adsorb larger volume of hydrogen gas ?
(a) Finely divided platinum
(b) Colloidal solution of palladium
(c) Small pieces of palladium
(d) A single metal surface of platinum
Answer:
(b) Colloidal solution of palladium

Question 16.
Which kind of catalysis can be explained on the basis of adsorption theory ?
(a) Homogeneous catalysis
(b) Heterogeneous catalysis
(c) Negative catalysis
(d) Auto catalysis
Answer:
(b) Heterogeneous catalysis

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 17.
The oxide of nitrogen which acts as a catalyst in lead chamber proces is …………
(a) NO
(b) NO2
(c) N2O4
(d) N2O5
Answer:
(a) NO

Question 18.
Shape-selective catalysis is a reaction catalysed by …………….
(a) zeolites
(b) enzymes
(c) platinum
(d) Ziegler-Natta catalyst
Answer:
(a) zeolites

Question 19.
The activity of an enzyme becomes ineffective ……….
(a) at low temperature
(b) at atmospheric pressure
(c) at high temperature
(d) in aqueous medium
Answer:
(c) at high temperature

Question 20.
The size of colloidal particles ranges between ………….
(a) 10-7 – 10-9cm
(b) 10-9 -101 cm
(c) 10-5 – 10-7cm
(d) 10-2 – 10-3cm
Answer:
(c) 10-5 – 10-7cm

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 21.
Which of the following will not form a colloidal system ?
(a) Solid-gas
(b) Liquid-gas
(c) Gas-gas
(d) Gas-liquid
Answer:
(c) Gas-gas

Question 22.
Fog is an example of colloidal system of ………….
(a) liquid in gas
(b) gas in liquid
(c) solid in gas
(d) gas in solid
Answer:
(a) liquid in gas

Question 23.
A colloidal system in which liquid is dispersed phase and solid is dispersion medium is classified as ………….
(a) gel
(b) sol
(c) emulsion
(d) aerosol
Answer:
(a) gel

Question 24.
Which of the following example is correctly matched ?
(a) Butter – gel
(b) Smoke – emulsion
(c) Paint – foam
(d) Milk – aerosol
Answer:
(a) Butter – gel

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 25.
Which of the following factors contribute towards higher stability of lyophilic colloid ?
(a) Charge on their particles
(b) Attractive forces between particles
(c) Small size of their particles
(d) High solvation due to a layer of dispersion medium
Answer:
(d) High solvation due to a layer of dispersion medium

Question 26.
A lyophobic colloid cannot be formed by ………….
(a) mixing dispersed phase and dispersion medium
(b) chemical reactions like hydrolysis
(c) exchange of solvent
(d) geptisation
Answer:
(a) mixing dispersed phase and dispersion medium

Question 27.
Which of the following is not correctly matched ?
(a) Gelatin – Lyophilic colloid
(b) Gold sol – Lyophilic colloid
(c) Arsenious sulphide – Lyophobic colloid
(d) Ferric hydroxide – Lyophobic colloid
Answer:
(b) Gold sol – Lyophilic colloid

Question 28.
The substances which behave as colloidal solutions at higher concentration are called ………….
(a) associated colloids
(b) multimolecular colloids
(c) macromolecular colloids
(d) protective colloids
Answer:
(a) associated colloids

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 29.
The formation of micelles takes place only above …………..
(a) critical temperature
(b) Kraft temperature
(c) inversion temperature
(d) absolute temperature
Answer:
(b) Kraft temperature

Question 30.
The critical micelle concentration (CMC) is defined as…………….
(a) the concentration at which micellization starts
(b) the concentration at which micelle starts behaving like an electrolyte
(c) the concentration at which dispersed phase is separated from dispersion medium
(d) the concentration at which a colloid is converted to suspension
Answer:
(a) the concentration at which micellization starts

Question 31.
At CMC (critical micelle concentration) the surface molecules
(a) dissociate
(b) associate
(c) become bigger in size due to adsorption
(d) become smaller in size due to decomposition
Answer:
(b) associate

Question 32.
Soap mixed with water below critical micelle concentration behaves as
(a) associated colloid
(b) macromolecular colloid
(c) normal electrolytic solution
(d) multimolecular colloid
Answer:
(c) normal electrolytic solution

Question 33.
White of an egg whipped with water acts as …………………
(a) macromolecular colloid
(b) associated colloid
(c) molecular colloid
(d) normal electrolytic solution
Answer:
(a) macromolecular colloid

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 34.
Which of the processes is being shown in the figure ?
Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry 2
(a) Electrodialysis
(b) Dialysis
(c) Electroosmosis
(d) Eelctrophoresis
Answer:
(a) Electrodialysis

Question 35.
Which of the following is not a method of removing impurities from a colloidal sol ?
(a) Electrodialysis
(b) Ultrafiltration
(c) Ultra centrifugation
(d) Distillation
Answer:
(d) Distillation

Question 36.
Tyndall effect is not observed in ………………
(a) smoke
(b) emulsions
(c) sugar solution
(d) gold sol
Answer:
(c) sugar solution

Question 37.
Which of the following systems will show Tyndall effect ?
(a) Aqueous solution of sodium chloride
(b) Aqueous solution of aluminium hydroxide
(c) Aqueous solution of glucose
(d) Aqueous solution of urea
Answer:
(b) Aqueous solution of aluminium hydroxide

Question 38.
Which of the following is not an explanation for the origin of charge on the colloidal particles ?
(a) Due to frictional electrification
(b) Due to dissociation of surface molecules
(c) Due to electrophoresis
(d) Due to selective adsorption of ions
Answer:
(c) Due to electrophoresis

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 39.
Movement of dispersion medium under the influence of electric field is known as ……………
(a) electrodialysis
(b) electrophoresis
(c) electroosmosis
(d) cataphoresis
Answer:
(c) electroosmosis

Question 40.
Why is alum added to water containing suspended impurities ?
(a) To make a colloidal solution
(b) To coagulate the suspended impurities
(c) To remove impurities of calcium and magnesium
(d) To protect the colloidal solution from getting precipitated
Answer:
(b) To coagulate the suspended impurities

Question 41.
Which of the following acts as the best coagulating agent for ferric hydroxide sol ?
(a) Potassium ferrocyanide
(b) Potassium chloride
(c) Potassium oxalate
(d) Aluminium chloride
Answer:
(a) Potassium ferrocyanide

Question 42.
Why is gelatin mixed with gold sol ?
(a) Gold sol is lyophobic sol, gelatin acts as stabilising agent
(b) Gold sol is lyophilic sol, gelatin acts as stabilising agent
(c) Gelatin produces negative charge on gold particles in gold sol
(d) Gelatin helps gold sol to get its critical micelle concentration
Answer:
(a) Gold sol is lyophobic sol, gelatin acts as stabilising agent

Question 43.
Which of the following is not a method for coagulation of lyophobic sols ?
(a) By electrophoresis
(b) By mixing oppositely charged sols
(c) By adding electrolyte
(d) By adding a protective colloid
Answer:
(d) By adding a protective colloid

Question 44.
What happens when a lyophilic sol is added to a lyophobic sol ?
(a) Lyophilic sol is protected
(b) Lyophobic sol is protected
(c) Both the sols are coagulated
(d) Electrophorsis takes place
Answer:
(b) Lyophobic sol is protected

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 45.
Which of the following is not a correct match ?
(a) Butter- OW type emulsion
(b) Vanishing cream-O/W type emulsion
(c) Milk – OW type emulsion
(d) Cream – W/O type emulsion
Answer:
(a) Butter- OW type emulsion

Question 46.
Which of the following is not an example of an emulsifying agent ?
(a) Proteins
(b)Gums
(c) Soaps
(d) Electrolytes
Answer:
(d) Electrolytes

Question 47.
The separation of an emulsion into its constituent liquids is known as
(a) emulsification
(b) protection of colloid
(c) coagulation
(d) demulsification
Answer:
(d) demulsification

Question 48.
Which of the following processes does not occur at the interface of phases ?
(a) Crystallisation
(b) Heterogeneous catalysis
(c) Homogeneous catalysis
(d) Corrosion
Answer:
(c) Homogeneous catalysis

Question 49.
At the equilibrium position in the process of adsorption …………
(a) ΔH > 0
(b) ΔH = TΔS
(c) ΔH>TΔS
(d) ΔH<TΔS
Answer:
(b) ΔH = TΔS

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 50.
Which of the following interfaces cannot be obtained ?
(a) Liquid-Liquid
(b) Solid-Liquid
(c) Liquid-Gas
(d) Gas-Gas
Answer:
(d) Gas-Gas

Question 51.
The term ‘sorption’ stands for………………
(a) absorption
(b) adsorption
(c) both absorption and adsorption
(d) desorption
Answer:
(c) both absorption and adsorption

Question 52.
Extent of physisorption of a gas increases with……………
(a) increase in temperature
(b) decrease in temperature
(c) decrease in surface area of adsorbent
(d) decrease in strength of van der Waals forces
Answer:
(b) decrease in temperature

Question 53.
Which one of the following is not applicable to the phenomenon of adsorption ?
(a) ΔH > 0
(b) ΔG < 0
(c) ΔS < 0
(d) ΔH < 0
Answer:
(a) ΔH > 0

Question 54.
Which of the following is not a favourable condition for physical adsorption ?
(a) High pressure
(b) Negative ΔH
(c) Higher critical temperature of adsorbate
(d) High temperature
Answer:
(d) High temperature

Question 55.
Physical adsorption of a gaseous species may change to chemical adsorption with……………
(a) decrease in temperature
(b) increase in temperature
(c) increase in surface area of adsorbent
(d) decrease in surface area of adsorbent
Answer:
(b) increase in temperature

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 56.
Which of the following is an example of absorption ?
(a) Water on silica gel
(b) Water on calcium chloride
(c) Hydrogen on finely divided nickel
(d) Oxygen on metal surface
Answer:
(b) Water on calcium chloride

Question 57.
At high concentration of soap in water, soap behaves as ……..
(a) molecular colloid
(b) associated colloid
(c) macromolecular colloid
(d) lyophilic colloid
Answer:
(b) associated colloid

Question 58.
Method by which lyophobic sol can be protected ……….
(a) by addition of oppositely charged sol
(b) by addition of an electrolyte
(c) by addition of lyophilic sol
(d) by boiling
Answer:
(c) by addition of lyophilic sol

Question 59.
Freshly preparad precipitate sometimes gets converted to colloidal solution by……………
(a) coagulation
(b) electrolysis
(c) diffusion
(d) peptisation
Answer:
(d) peptisation

Bihar Board 12th Chemistry Objective Answers Chapter 5 Surface Chemistry

Question 60.
Which of the following electrolytes will have maximum coagulating value for Agl/Ag+ sol ?
(a) Na2S
(b) Na3PO4
(c) Na2SO4
(d) NaCI
Answer:
(b) Na3PO4

Question 61.
Which of the following process is responsible for the formation of delta at a place where rivers meet the sea ?
(a) Emulsification
(b) Colloid formation
(c) Coagulation
(d) Peptisation
Answer:
(c) Coagulation

Question 62.
Which of the following process is not responsible for the presence of electric charge on the sol particles ?
(a) Electron capture by sol particles
(b) Adsorption of ionic species from solution
(c) Formation of Helmholtz electrical double layer
(d) Adsorption of ionic species from solution
Answer:
(d) Adsorption of ionic species from solution

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Bihar Board 12th Physics Objective Questions and Answers

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 1.
The natural boron of atomic weight 10.81 is found to have two isotopes 10B and nB. The ratio of abundance of isotopes of natural boron should be
(a) 11: 10
(b) 81 : 19
(c) 10:11
(d) 19 : 81
Answer:
(d) 19 : 81

Question 2.
The mass number of iron nucleus is 56, the nuclear 1 density is
(a) 2.29 x 1016 kg m-3
(b) 2.29 x 1017 kg m-3
(c) 2.29 x 1018 kg m-3
(d) 2.29 x 1015 kg m-3
Answer:
(b) 2.29 x 1017 kg m-3

Question 3.
Two nuclei have their mass numbers in the ratio of 1: 3. The ratio of their nuclear densities would be
(a) (3)1/3 : 1
(b) 1 : 1
(c) 1 : 3
(d) 3 : 1
Answer:
(b) 1 : 1

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 4.
The radius of a spherical nucleus as measured by electron scattering is 3.6 fm. What is the mass number of the nucleus most likely to be?
(a) 27
(b) 40
(c) 56
(d) 120
Answer:
(a) 27

Question 5.
The ratio of the nuclear radii of the gold isotope \(\begin{array}{l}
197 \\
79
\end{array} \mathrm{Au}\) and silver isotope \(\begin{array}{l}
107 \\
47
\end{array} \mathrm{Ag}\) is
(a) 1.23
(b) 0.216
(c) 2.13
(d) 3.46
Answer:
(a) 1.23

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 6.
How much mass has to be converted into energy to produce electric power of 500 MW for one hour?
(a) 2 x 10-5 kg
(b) 1 x 10-5 kg
(c) 3 x 10-5 kg
(d) 4 x 10-5 kg
Answer:
(a) 2 x 10-5 kg

Question 7.
If in a nuclear fusion reaction, mass defect is 0.3%, then energy released in fusion of 1 kg mass
(a) 27 x 1010 J
(b)27 x 1011 J
(c) 27 x 1012 J
(d) 27 x 1013 J
Answer:
(d) 27 x 1013 J

Question 8.
The equivalent energy of 1 g of substance is
(a) 9 x 1013 J
(b) 6 x K)12 J
(c) 3 x 1013 J
(d) 6 x 1013 J
Answer:
(a) 9 x 1013 J

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 9.
Fission of nuclei is possible because the binding energy per nucleon in them
(a) increases with mass number at low mass numbers
(b) decreases with mass number at low mass numbers
(c) increases with mass number at high mass numbers
(d) decreases with mass number at high mass numbers
Answer:
(d) decreases with mass number at high mass numbers

Question 10.
Let mp be the mass of a proton, mn the mass of a neutron, M1 the mass of a \(\frac{20}{10} \mathrm{Ne}\) Ne nucleus and M2 the mass of a \(\frac{40}{20} \mathrm{Ca}\) nucleus. Then
(a) M2 = M1
(b) M2 > 2M1
(c) M2 < 2M1
(d) M1 < 10 (mn + mp)
Answer:
(d) M1 < 10 (mn + mp)

Question 11.
The half life of \(\begin{array}{l}
238 \\
92
\end{array} \mathrm{U}\) undergoing a-decay is 4.5 x 109 years. The activity of 1 g sample of is
(a) 1.23 x 104 Bq
(b) 1.23 x 105 Bq
(c) 1.23 x 103 Bq
(d) 1.23 x 106 Bq
Answer:
(a) 1.23 x 104 Bq

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 12.
The half life of a radioactive substance is 20 s, the time taken for the sample to decay by 7/8th of its initial value is
(a) 20 s
(b) 40 s
(c) 60 s
(d) 80 s
Answer:
(c) 60 s

Question 13.
The half life of a radioactive substance is 30 days What is the time takento disintegrate to 3/4th of its original mass?
(a) 30 days
(b) 15 days
(c) 60 days
(d) 90 days
Answer:
(c) 60 days

Question 14.
The half life of polonium is 140 days. In what time will 15 g of polonium be disintegrated out of its initial mass of 16 g?
(a) 230 days
(b) 560 days
(c) 730 days
(d) 160 days
Answer:
(b) 560 days

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 15.
A 280 day old radioactive substance shows an activity of 6000 dps, 140 days later its activity becomes 3000 dps. What was its initial activity?
(a) 20000 dps
(b) 24000 dps
(c) 12000 dps
(d) 6000 dps
Answer:
(b) 24000 dps

Question 16.
Tritium with a half-life of 12.5 years undergoing beta decay. What fraction of a sample of pure tritium will remain undecayed after 25 years.
(a) one half
(b) one fourth
(c) one third
(d) can’t say
Answer:
(b) one fourth

Question 17.
The decay constant, for a given radioactive sample, is 0.3465 day-1. What percentage of this sample will get decayed in a period of 4 days?
(a) 100%
(b) 50%
(c) 75%
(d) 10%
Answer:
(c) 75%

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 18.
Carbon dating is best suited for determining the age of fossils, if their age in years is of the order of
(a) 103
(b) 104
(c) 105
(d) 106
Answer:
(b) 104

Question 19.
The half life of \(\begin{array}{l}
90 \\
38
\end{array} \mathrm{Sr}\) is 28 years. The disintegration rate of 15 mg of this isotope is of the order of
(a) 1011 Bq
(b) 1010 Bq
(c) 107 Bq
(d) 109 Bq
Answer:
(b) 1010 Bq

Question 20.
A sample of radioactive material has mass m, decay constant λ, molecular weight M and Avogadro constant NA. The initial activity of the sample is
Am XmN A
\((a) \lambda m
(b) \frac{\lambda \mathrm{m}}{\mathrm{M}}
(c) \frac{\lambda m N_{A}}{M} \quad
(d) m N_{A} \lambda\)
Answer:
\((c) \frac{\lambda m N_{A}}{M} \quad\)

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 21.
Plutonium decays with half life of 24000 years. If plutonium is stored for 72000 years, the fraction of it that remains is
(a) 1/8
(b) 1/3
(c) 1/4
(d) 1/2
Answer:
(a) 1/8

Question 22.
The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an
(a) isomer of parent
(b) isotone of parent
(c) isotope of parent
(d) isobar of parent
Answer:
(c) isotope of parent

Question 23.
Which of the following cannot be emitted by radioactive substances during their decay?
(a) Neutrinos
(b) Protons
(c) Electrons
(d) Helium nuclei
Answer:
(b) Protons

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 24.
A radioactive decay can form an isotope of the original nucleus with the emission of particles
(a) one a and four β
(b) one a and two β
(c) one a and one β
(d) four a and one β
Answer:
(b) one a and two β

Question 25.
Consider a and 3 particles and y-rays each having an energy of 0.5 MeV. In the increasing order of penetrating power, the radiation are respectively
(a) α,β,γ
(b) α,γ,β
(c) β,γ,α
(d) γ,β,α
Answer:
(a) α,β,γ

Question 26.
An electron emitted in beta radiation originates from
(a) inner orbits of atom
(b) free electrons existing in the nuclei
(c) decay of a neutron in a nuclei
(d) photon escaping from the nucleus
Answer:
(c) decay of a neutron in a nuclei

Question 27.
Complete the series \(^6 \mathrm{He} \rightarrow \mathrm{e}^{+6} \mathrm{Li}+\)
(a) neutrino
(b) antineutrino
(c) proton
(d) neutron
Answer:
(a) neutrino

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 28.
A nucleus of Ux1 has a half life of 24.1 days. How long a sample of Ux1 will take to change to 90% of Ux1.
(a) 80 days
(b) 40 days
(c) 20 days
(d) 10 days
Answer:
(a) 80 days

Question 29.
An element A decays into an element C by a two step process A → B + 2He4 B → C + 2e. Then,
(a) A and C are isotopes
(b) A and C are isobars
(c) B and C are isotopes
(d) A and B are isobars
Answer:
(a) A and C are isotopes

Question 30.
The equation \(4_{1}^{1} H^{+} \rightarrow_{2}^{4} H e^{2+}+2 e^{-}+26 M e V\) represents
(a) β-decay
(b) γ-decay
(c) fusion
(d) fission
Answer:
(c) fusion

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 31.
Light energy emitted by star is due to
(a) breaking of nuclei
(b) joining of nuclei
(c) burning of nuclei
(d) reflection of solar light
Answer:
(b) joining of nuclei

Question 32.
Fast neutrons can easily be slowed down by
(a) the use of lead shielding
(b) passing them through water
(c) elastic collisions with heavy nuclei
(d) applying a strong electric field
Answer:
(b) passing them through water

Question 33.
In the given reactions, which of the following nuclear fusion reaction is not possible?
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 1
Answer:
(a)

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 34.
If 200 MeV energy is released in the fission of a single nucleus of \(_{ 92 }^{ 235 }{ U }\) the fission which are required to produce a power of 1 kW is
(a) 3,125 x 1013
(b) 1.52 x 106
(c) 3.125 x 1012
(d) 3.125 x 1014
Answer:
(a) 3,125 x 1013

Question 35.
The gravitational force between a H-atom and another particle of mass m will be given by Newton’s law : \(\mathbf{F}=\mathbf{G} \frac{\mathbf{M} \cdot \mathbf{m}}{\mathbf{r}^{2}}\) is in km and
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 2
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 3
Answer:
(b)

Question 36.
When a nucleus in an atom undergoes a radioactive decay, the electronic energy levies of the atom
(a) do not change for any type of radioactivity
(b) change for a and P radioactivity but not for y- radioactivity
(c) change for a-radioactivity but not for others
(d) change for P-radioactivity but not for others.
Answer:
(b) change for a and P radioactivity but not for y- radioactivity

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Hints & Explanations

Question 1.
(d) Let abundance of B10 be x%
Abundance of B11 = (100 – x)%
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 4

Question 3.
(b) A1 : A2 = 1 : 3
Their radii will be in the ratio
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 5
Their nuclear densities will be the same

Question 4.
(a) Nuclear radius, R = R0(A)1/3, where A is the mass
number of a nucleus
Given, R = 3.6 fm
∴ 3.6fm = (1.2fm)(A1/3) (∴ R0 = 1.2fm)
or, A = (3)3 = 27

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 5.
(a) Here, A1 = 197 and A2 = 107
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 6

Question 6.
(a) Here, P = 500 MW = 5 x 108 W,t = 1 h = 3600 s
Energy produced, E = P x / = 5 x 108 x 3600
= 18 x 1011 J
As E = mc2
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 7

Question 7.
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 8

Question 8.
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 9

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 11.
(a) T1/2 = 4.5 x 109 years
= 4.5 x 109 x 3.16 x 107 : 1.42 x 1017 s
One kmol of any isotope contains Avogadro’ number of atoms, so 1 g of \(_{ 92 }^{ 238 }{ U }\) contains
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 10

Question 12.
(c) After three half lives, the fraction of undecayed nuclei \(=\left(\frac{1}{2}\right)^{3}=\frac{1}{8}\)
∴ Time taken for the sample to decay by (1 – 1/8)th or \(\frac{7^{t h}}{8}\) of initial value. = 3T1/2 = 3 x 20 = 60 s

Question 13.
(c) Here, \(\frac{N_{0}-N}{N_{0}}=\frac{3}{4} \text { or } \frac{N}{N_{0}}=\frac{1}{4}=\left(\frac{1}{2}\right)^{2}\)
∴ No of half lives, n = 2
Time taken to disintegrate
= Half life x No. of half lives
= 30 x 2= 60 days

Question 14.
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 11

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 17.
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 12
Hence, sample left undecayed after a period of 4 days.
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 13
∴ Sample decayed = 75%

Question 18.
(b) Carbon dating is best suited for determining the age
of fossils, if their age is of the order of 104 years.

Question 19.
(b) Here, T1/2 = 28 years = 28 x 3.154 x 107 s
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 14

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei

Question 28.
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 15
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 16

Question 34.
Let the number of fissions per second be n. Energy released per second
= n x 200 MeV = n x 200 x 1.6 x 10~13 J

Energy required per second = power x time = 1 kW x Is = 1000J
Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei in english medium 17

Bihar Board 12th Physics Objective Answers Chapter 13 Nuclei