7/30/2019 Jee Main 2013 Key

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JEE Main 2013 - Answer Key Code -Q

Question QuestionQuestionQuestionQuestionQuestionAnswer Answer AnswerAnswerAnswerAnswer

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Q.1 Anunknown alcohol istreated withthe "Lucasreagent" to determine whether the alcohol is

primary, secondaryor tertiary. Which alcoholreacts fastest andbywhat mechanism:(1) tertiaryalcohol by SN1(2) secondary alcohol by SN2

(3) tertiaryalcohol by SN2(4) secondary alcohol by SN1Ans. 1

Q.2 The first ionisation potential of Nais 5.1 eV.The value of electron gain enthalpyof Na+ will

be:(1) 5.1 eV (2) 10.2 eV(3) +2.55 eV (4) 2.55 eV

Ans. 1

Q.3 Stability of the species Li2, Li2 and Li2+

increases in theorder of:(1) Li2 < Li2

+ < Li2

(2) Li2 < Li2 < Li2+

(3) Li2 < Li2 < Li2+

(4) Li2 < Li2+ < Li2

Ans. 1

Q.4 The molarityof a solution obtainedbymixing

750mLof0.5(M)HClwith250mLof2(M)HCl willbe:(1) 1.00 M (2) 1.75 M(3) 0.975 M (4) 0.875 M

Ans. 4

Q.5 Which ofthefollowing isthewrong statement?(1)O3 molecule is bent(2) Ozone is violet-black in solid state(3) Ozone is diamagnetic gas

(4) ONCl and ONO are not isoelectronic.Ans. 4

Q.6 Four successive members of the first rowtransition elementsarelistedbelowwithatomicnumbers. Which one of them is expected to

have thehighest0

M/M 23E value?

(1) Mn (Z = 25) (2) Fe (Z = 26)(3) Co (Z = 27) (4) Cr (Z = 24)

Ans. 3

Q.7 A solutionof () 1chloro 1 phenylethaneon tolueneracemisesslowlyin thepresence ofa small amount of SbCl5 due to theformationof::(1) carbene (2) carbocation(3) free radical (4) carbanion

Ans. 2

Q.8 The coagulating power of electrolyteshavingions Na+, Al3+ and Ba2+ for arsenic sulphidesol increases in the order :(1) Na+ < Ba2+ < Al3+

(2) Ba2+ < Na+ < Al3+

(3) Al3+ < Na+ < Ba2+

(4) Al3+ < Ba2+ < Na+

Ans. 1

Q.9 How manylitres of water must be added to 1litre of an aqueous solution of HCl with a pHof 1 to create an aqueous solution with pH of2?(1) 0.9 L (2) 2.0 L(3) 9.0 L (4) 0.1 L

Ans. 3

Q.10 Which one of the following molecules isexpectedto exhibit diamagnetic behaviour?

(1) N2 (2) O2(3) S2 (4) C2

Ans. 1 and 4

Q.11 Whichof the following arrangements doesnotrepresent the correct order of the propertystatedagainst it?(1) Ni2+ < Co2+ < Fe2+ < Mn2+ : ionic size(2) Co3+ < Fe3+ < Cr3+ < Sc3+ : stability inaqueous solution

(3) Sc< Ti < Cr < Mn : number ofoxidationstates(4) V2+ < Cr2+ < Mn2+ < Fe2+ : paramagnetic

behaviourAns. 2 and 4

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Q.12 Experimentallyit was found thata metal oxidehas formula M0.98O. Metal M, is present asM2+ andM3+ in its oxide. Fraction ofthemetalwhich exists as M3+ would be :(1) 4.08 % (2) 6.05 %(3) 5.08 % (4) 7.01 %

Ans. 1

Q.13 A compound with molecular mass 180 isacylated with CH3COCl to get a compoundwithmolecularmass 390. Thenumberof aminogroups present per molecule of the formercompoundis:(1) 5 (2) 4(3) 6 (4) 2

Ans. 1

Q.14 Given

V74.0E0Cr/Cr3

; V51.1E0

Mn/MnO 24

V33.1E0Cr/OCr 3272

; V36.1E0 Cl/Cl

Based on the data given above, strongestoxidisingagentwillbe:(1) Cr3+ (2) Mn2+

(3) MnO4 (4) ClAns. 3

Q.15 Arrange the following compounds in order ofdecreasing acidity:

OH OH OH OH

Cl CH3 NO2 OCH3(I) (II) (III) (IV)

(1) I > II > III > IV(2) III > I > II > IV(3) IV > III > I > II(4) II > IV > I > III

Ans. 2

Q.16 The rate of a reaction doubles when itstemperature changes from 300 K to 310 K.Activation energy of such a reaction will be:(R = 8.314 JK1 mol1 and log 2 = 0.301)(1) 48.6 kJ mol1

(2) 58.5 kJ mol1

(3) 60.5 kJ mol

1

(4) 53.6 kJ mol1

Ans. 4

Q.17 Synthesis of each molecule of glucose inphotosynthesis involves:(1) 10 molecules ofATP(2) 8 molecules ofATP(3) 6 molecules ofATP(4) 18 molecules ofATP

Ans. 4

Q.18 Which ofthe followingcomplex species isnotexpectedto exhibit opticalisomerism?(1) [Co(en)2Cl2]

+

(2) [Co(NH3)3Cl3](3) [Co(en)(NH3)2Cl2]

+

(4) [Co(en)3]3+

Ans. 2

Q.19 A piston filled with 0.04 mol of an ideal gas

expands reversibly from 50.0 mL to 375 mLat a constanttemperature of 37.0C.As it doesso, it absorbs 208 J of heat. The values of qand w for the process will be:(R = 8.314 J / mol K) (ln 7.5 = 2.01)(1) q = 208 J, w = 208 J(2) q = 208 J, w = +208 J(3) q = +208 J, w = +208 J(4) q = +208 J, w = 208 J

Ans. 4

Q.20 Agaseous hydrocarbon gives uponcombustion0.72 g of water and 3.08 g of CO2. Theempirical formulaofthe hydrocarbonis:(1) C3H4 (2) C6H4(3) C7H8 (4) C2H4

Ans. 3

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Q.21 The order of stability of the followingcarbocations:

CH = CH CH ; CH CH CH2 2 3 2 2 ;

(II) (III)(I)

CH2

is(1) II > III > I (2) I > II > III(3) III > I > II (4) III > II > I

Ans. 3

Q.22 Which of the following represents thecorrectorderof increasingfirst ionization enthalpyforCa, Ba, S, Se and Ar?

(1) S < Se < Ca < Ba < Ar(2) Ba < Ca < Se < S < Ar(3) Ca < Ba < S < Se < Ar(4) Ca < S < Ba < Se < Ar

Ans. 2

Q.23 For gaseous state, if most probable speed is

denoted by C*, average speed by C and

mean square speed by C, then for a largenumber ofmolecules the ratios ofthesespeeds

are:(1) C* : C : C = 1.128 : 1.225 : 1

(2) C* : C : C = 1 : 1.128 : 1.225

(3) C* : C : C = 1 : 1.225 : 1.128

(4) C* : C : C = 1.225 : 1.128 : 1Ans. 2

Q.24 The gas leaked from a storage tank of theUnion Carbideplant in Bhopalgas tragedywas:

(1)Methylamine(2)Ammonia(3) Phosgene(4) Methylisocyanate

Ans. 4

Q.25 Consider thefollowing reaction:xMNO4 + yC2O4

2 + zH+

xMn2+ + 2yCO2 + 2

zH2O

The value ofx, y and z in the reaction are,respectively:

(1) 2, 5 and 8 (2) 2, 5 and 16(3) 5, 2 and 8 (4) 5, 2 and 16

Ans. 2

Q.26 Whichof the followingexistsascovalentcrystalin thesolidstate?(1) Silicon (2) Sulphur (3) Phosphorus (4) Iodine

Ans. 1

Q.27 Compound (A), C8H9Br, gives a whiteprecipitate when warmed with alcoholicAgNO3. Oxidation of (A) gives an acid (B),C8H6O4. (B) easilyformsanhydrideonheating.Identifythe compound (A).

(1)

C H2 5

Br

(2)

CH2Br

CH3

(3)

CH2Br

CH3

(4)

CH2Br

CH3

Ans. 3

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Q.28 Energyof anelectron is given by

E = 2.178 1018 J

2

2

n

Z. Wavelength of

light required to excite an electron in anhydrogen atom from level n = 1 to n = 2 will

be:(h = 6.62 1034 Js and c = 3.0 108 ms1)(1) 2.816 107 m(2) 6.500 107 m(3) 8.500 107 m(4) 1.214 107 m

Ans. 4

Q.29 An organic compoundA upon reacting withNH3 gives B. On heating B give C, C in

presence of KOH reacts with Br2 to giveCH3CH2NH2.Ais(1) CH3CH2CH2COOH

(2)

CH3

CH3CHCOOH

(3) CH3CH2COOH(4) CH3COOH

Ans. 3

Q.30 In which of the following pairs ofmolecules /

ions, both the species are not likely to exist?(1) H2, He2

2 (2) H22+, He2

(3) H2, He22+ (4) H2

+, He22

Ans. 2

Q.31 The circlepassing through (1, 2)and touchingthe axis of x at (3, 0) also passes through the

point(1) (2, 5)(2) (5, 2)

(3) ( 2, 5)(4) ( 5, 2)

Ans. [2]

Q.32 ABCD is a trapezium such that AB and CDare parallel and BC CD. IfADB = ,BC = p and CD = q, then AB is equal to

(1)

sinqcosp

cosqp 22

(2)

sinqcosp

qp22

22

(3) 2

22

)sinqcosp(

sin)qp(

(4)

sinqcosp

sin)qp( 22

Ans. [4]

Q.33 Given : A circle 2x2 + 2y2 = 5 and a parabola

y2 = 4 5 x.

Statement-I: An equation of a common

tangent to these curves is y = x + 5 .

Statement-II: If the line y = mx +m

5

(m0)istheircommontangent,then m satisfiesm4 3m2 + 2 = 0.

(1) Statement-I is true, Statement-II is true,Statement-II is not a correct explanation forStatement-I.(2) Statement-Iis true, Statement-II is false.(3) Statement-Iis false, Statement-II is true.(4) Statement-I is true, Statement-II is true,Statement-II is a correct explanation forStatement-I.

Ans. [1]

Q.34 A ray of light along x + 3 y = 3 gets

reflected upon reaching x-axis,the equation ofthereflected ray is

(1) 3 y = x 3

(2) y = 3 x 3

(3) 3 y = x 1

(4) y = x + 3

Ans. [1]

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Q.35 All the studentsof a class performed poorlyinMathematics. The teacher decided to givegrace marks of 10 to each of the students.Which ofthefollowingstatisticalmeasureswillnot change even after the grace were given?(1) median (2) mode

(3) variance (4) meanAns. [3]

Q.36 If x, y, z are in A.P. and tan1x, tan1y andtan1z are also inA.P., then(1) 2x = 3y = 6z(2) 6x = 3y = 2z(3) 6x = 4y = 3z(4) x = y = z

Ans. [4]

Q.37 If dx)x(f = (x), then dx)x(fx 35 isequal to

(1)3

1x3(x3) 3 dx)x(x 33 + C

(2)3

1x3(x3) dx)x(x 32 + C

(3) dx)x(x)x(x31 3333 + C

(4) dx)x(x)x(x31 3233 + C

Ans. [2]

Q.38 The equation of thecircle passing through the

foci of the ellipse9

y

16

x 22 = 1 and having

centre at (0, 3) is(1) x2 + y2 6y + 7 = 0(2) x2 + y2 6y 5 = 0(3) x2 + y2 6y + 5 = 0(4) x2 + y2 6y 7 = 0

Ans. [4]

Q.39 The x-coordinateofthe incentreofthe trianglethat has the coordinates of mid points of itssides as (0, 1), (1, 1) and (1, 0) is

(1) 2 2 (2) 1 + 2

(3) 1 2 (4) 2 + 2Ans. [1]

Q.40 The intercepts on x-axis made bytangents to

the curve,y= x

0

dt|t| , xR,whichare parallel

to the line y = 2x are equal to(1) 2 (2) 3(3) 4 (4) 1

Ans. [4]

Q.41 The sum of first 20 terms of the sequence0.7, 0.77, 0.777, .........., is

(1)9

7(99 1020)

(2)81

7(179 + 1020)

(3)9

7(99 +1020)

(4)81

7(179 1020)

Ans. [2]

Q.42 ConsiderStatement-1: (p ~ q) (~ p q) is afallacy.Statement-2: (p q) (~ q ~ p) is atautology.(1) Statement-I is true, Statement-II is true,

Statement-II is not a correct explanation forStatement-I.(2) Statement-Iis true, Statement-II is false.(3) Statement-Iis false, Statement-II is true.(4) Statement-I is true, Statement-II is true,Statement-II is a correct explanation forStatement-I.

Ans. [1]

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Q.43 The area (in square units) bounded by the

curves y = x , 2y x + 3 = 0, x-axis andlyingin thefirst quadrant is(1) 36 (2) 18

(3)4

27(4) 9

Ans. [4]

Q.44 The expressionAtan1

Acot

Acot1

Atan

can be

written as(1) sec A cosec A + 1(2) tan A + cot A(3) sec A + cosec A(4)sinAcosA+1

Ans. [1]

Q.45 The real number k for which the equation2x3 + 3x + k = 0 has twodistinct real roots in[0, 1](1) lies between 2 and 3.(2) lies between 1 and 0.(3) does not exist.(4) lies between 1 and 2.

Ans. [3]

Q.46x4tanx

)xcos3()x2cos1(Lim

0x

is equal to

(1)2

1(2) 1

(3) 2 (4)4

1

Ans. [3]

Q.47 Let Tnbe the number of all possible trianglesformed byjoining vertices ofann-sidedregular

polygon. If Tn+1 Tn = 10, then thevalue ofnis(1) 5 (2) 10(3) 8 (4) 7

Ans. [1]

Q.48 Atpresent,a firmismanufacturing 2000items.It is estimated that the rate of change of

production P w.r.t. additional number of

workers x is given bydx

dP= 100 12 x .

If the firmemploys 25 moreworkers, then the

new level ofproduction ofitems is(1) 3000 (2) 3500(3) 4500 (4) 2500

Ans. [2]

Q.49 Statement-1: The value of the integral

3

6xtan1

dxis equal to

6

.

Statement-2: b

a

dx)x(f = b

a

dx)xba(f .

(1) Statement-I is true, Statement-II is true,Statement-II is not a correct explanation forStatement-I.(2) Statement-Iis true, Statement-II is false.(3) Statement-Iis false, Statement-II is true.(4) Statement-I is true, Statement-II is true,Statement-II is a correct explanation forStatement-I.

Ans. [3]

Q.50 If P =

44233131

is the adjoint of a 3 3

matrixAand|A|=4,then is equal to(1) 11 (2) 5(3) 0 (4) 4

Ans. [1]

Q.51 The numberof valuesof k,forwhich the systemofequations:(k + 1) x + 8y = 4kkx + (k + 3) y = 3k 1has nosolution is(1) 1 (2) 2(3) 3 (4)infinite

Ans. [1]

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Q.52 If y = sec (tan1x), thendx

dyatx=1isequalto

(1)2

1(2) 1

(3) 2 (4) 2

1

Ans. [4]

Q.53 If the lines1

2x =

1

3y =

k

4z

and

k

1x =

2

4y =

1

5z are coplanar, then k

canhave(1) exactly onevalue

(2) exactlytwo values(3) exactly three values(4) any value

Ans. [2]

Q.54 LetA and B betwo sets containing2 elementsand 4 elements respectively. The number ofsubsets ofA B having 3 or more elements is(1) 220 (2) 219(3) 211 (4) 256

Ans. [2]

Q.55 If t he v ector s k4i3AB an d

k4j2i5AC are the sides of a triangleABC, thenthe length ofthemedian throughAis

(1) 72 (2) 33

(3) 45 (4) 18

Ans. [2]

Q.56 A multiple choiceexaminationhas 5 questions.Each question hasthree alternative answersofwhich exactly oneis correct. The probabilitythata student willget 4 ormorecorrect answers

just byguessing is

(1) 53

13

(2) 53

11

(3) 53

10(4) 53

17

Ans. [2]

Q.57 If z is a complex numberofunit modulus and

argument , then arg

z1

z1equals

(1) 2

(2)

(3) (4) Ans. [2]

Q.58 If the equation x2 + 2 x + 3 = 0 a n dax2 + b x + c = 0 , a , b , c R, have a commonroot,thena:b:cis(1) 3 : 2 : 1 (2) 1 : 3 : 2(3) 3 : 1 : 2 (4) 1 : 2 : 3

Ans. [4]

Q.59 Distance between two parallel planes2x + y + 2z = 8 and 4x + 2y + 4z + 5 = 0 is

(1)2

5(2)

2

7

(3)2

9(4)

2

3

Ans. [2]

Q.60 The term independent of x in expansion of

10

2

1

3

1

3

2

xx

1x

1xx

1x

is

(1) 120 (2) 210(3) 310 (4) 4

Ans. [2]

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Q.61 In an LCR circuit as shown below bothswitches are open initially. Now switch S1 isclosed, S2 kept open. (q is charge on thecapacitor and = RC is Capacitive timeconstant).Whichofthefollowing statement iscorrect ?

V

R

C

L

S1

S2

(1) At t = , q = CV/2(2) At t = 2, q = CV(1 e2)

(3) At t =2 , q = CV(1 e1)

(4) Work done by the battery is half of theenergy dissipated in the resistor

Ans. [2]

Q.62 A diode detectoris usedtodetectanamplitudemodulated wave of 60%modulationbyusinga condenser of capacity 250 pico farad in

parallel with a load resistance 100 kilo ohm.

Find themaximummodulatedfrequencywhichcould be detected by it.(1) 1 0.62 kHz (2) 5.31 MHz(3) 5.31 kHz (4) 10.62 MHz

Ans. [1]

Q.63 The supply voltage to a room is 120 V. Theresistanceofthe leadwires is 6.A60Wbulbis alreadyswitched on. What is the decreaseof voltage across the bulb, when a 240 W

heater is switchedon in parallel to the bulb ?(1) 2.9 Volt (2) 13.3 Volt(3) 10.04 Volt (4)zeroVolt

Ans. [3]

Q.64 A uniform cylinder of length L and mass Mhaving cross-sectional areaA is suspended,with itslength vertical, from a fixed pointbyamassless spring, such that it is half submergedin a liquid ofdensityat equilibrium position.The extension x0 of the spring when it is in

equilibriumis:

(1)

M

LA1

k

Mg(2)

M2

LA1

k

Mg

(3)

M

LA1

k

Mg(4)

k

Mg

(Here k is spring constant)Ans. [2]

Q.65 Two charges, each equal to q, are kept at x =

a and x = a on the x-axis.A particle of mass

m and charge q0 = 2

qis placed at the origin. If

chargeq0 is given a small displacement (y

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Q.67 The anode voltage ofa photocell is kept fixed.The wavelength of the light falling on thecathodeis graduallychanged.Theplate currentI ofthe photocell varies as follows :

(1)

I

O(2)

I

O

(3)

O

I

(4)

I

O

Ans. [3]

Q.68 Two coherent point sources S1 and S2 areseparatedbya small distance'd' asshown. The

fringes obtained on the screen will be :

D

S1 S2

d

Screen

(1) straight lines (2) semi-circles(3) concentric circles (4) points

Ans. [3]

Q.69 A metallic rod of length lis tied to a string oflength21and made torotate with angularspeedona horzontal table withone end ofthe stringfixed. If there is a vertical magnetic field 'B' inthe region, the e.m.f. induced across the endoftherodis

(1)2

B3 2l(2)

2

B4 2l

(3)2

B5 2l(4)

2

B2 2l

Ans. [3]

Q.70 In a hydrogen like atom electron makestransition from an energylevel with quantumnumber n to another with quantum number(n 1). If n >>1, the frequency of radiationemitted is proportionalto

(1) 2n

1

(2) 23n

1

(3) 3n

1(4)

n

1

Ans. [3]

Q.71 Assume that a drop of liquid evaporates bydecrease in its surface energy, so that itstemperature remains unchanged. Whatshould

be the minimum radius of the dropfor this to

be possible?The surface tension is T, densityof liquid is and L is its latent heat ofvaporization.

(1) LT (2) LT

(3) LT2 (4) TL

Ans. [3]

Q.72 The graph between angle of deviation ()andangle of incidence (i) for a triangular prism is

represented by :

(1)

O i

(2)

O i

(3)

O i

(4)

O i

Ans. [2]

Q.73 Let [0] denotethedimensionalformula ofthepermittivityof vacuum.If M = mass, L= length,T = time and A = electric current, then(1) [0] = [M

1L3T4A2](2) [0] = [M

1L2T1A2](3) [0] = [M

1L2T1A](4) [0] = [M

1L3T2A]Ans. [1]

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Q.74

v0v

2v0

p p0

2p0

The above p-v diagram represents thethermodynamiccycle of an engine, operatingwith anideal monoatomic gas. The amount ofheat, extracted fromthesourceina singlecycle,is

(1) 00vp2

13

(2) 00vp

2

11

(3) 00vp4 (4) 00vpAns. [1]

Q.75 A sonometer wire oflength 1.5 m is made ofsteel.Thetensionin itproducesanelastic strainof 1%. What is the fundamental frequency ofsteelifdensityand elasticityofsteelare 7.7103

kg/m3 and2.21011N/m2 respectively?(1) 178.2 Hz (2) 200.5 Hz(3) 770 Hz (4) 188.5 Hz

Ans. [1]

Q.76 This questionhas statement I and statement II.Of thefour choices given after the statements,choose the one that best describes the twostatements.Statement-I: Higher the range, greater is theresistance of ammeter.Statement-II: To increase the range ofammeter, additional shunt needs to be usedacross it.(1) Statement-I is true, Statement-II is true,Statement-II is notthe correct explanation ofStatement-I.(2) Statement-Iis true, Statement-II is false.(3) Statement-Iis false, Statement-II is true.(4) Statement-I is true, Statement-II is true,Statement-II is the correct explanation ofStatement-I.

Ans. [3]

Q.77 Whatistheminimum energyrequiredto launchasatelliteofmassmfromthesurfaceofaplanetofmassMandradiusRinacircularorbitatanaltitude of 2R?

(1)R3

GmM2(2)

R2

GmM

(3)R3

GmM(4)

R6

GmM5

Ans. [4]

Q.78 A projectile is given an initial velocity of

j2i m/s, where i is along theground and

j is along the vertical. If g = 10 m/s2, the

equation of its trajectoryis(1) y = 2x 5x2 (2) 4y = 2x 5x2

(3) 4y = 2x 25x2 (4) y = x 5x2

Ans. [1]

Q.79 Two capacitors C1 and C2 are charged to120V and 200V respectively. It is found that

by connecting them together the potential oneach one can be made zero. Then(1) 3C1 = 5C2 (2) 3C1 + 5C2 = 0(3) 9C1 = 4C2 (4) 5C1 = 3C2

Ans. [1]

Q.80 A hoopof radius r andmass m rotating withanangular velocity 0 is placed on a roughhorizontal surface. The initial velocity of thecentre of the hoop is zero. What will be thevelocityofthecentreofthehoopwhenitceasesto slip?

(1)3

r 0(2)

2

r 0

(3) 0r (4) 4r 0

Ans. [2]

7/30/2019 Jee Main 2013 Key

12/14

Q.81 An ideal gas enclosed in a vertical cylindricalcontainer supposrs a freelymoving piston ofmass M. The poston and the cylinder haveequal cross sectional areaA. When the pistonis in equilibrium, the volume of the gas is V0and its pressure is P0. The piston is slightly

displaced from the equilibrium position andreleased. Assuming that the system iscompletely isolated from its surrounding, the

piston executes a simeharmonic motion withfrequency.

(1) 200

A

MPV

2

1(2)

0

02

MV

PA

2

1

(3)0

0

PA

MV

2

1

(4) MVPA

2

1

0

0

Ans. [2]

Q.82 A chargeQ isuniformly distributed overa longrodAB oflength Las shown in the figure. Theelectric potential at the point O lying at adistanceL fromthe endAis

A B

LLO

(1) L4

Q3

0 (2) 2nL4

Q

0l

(3) L4

2nQ

0l

(4) L8

Q

0

Ans. [3]

Q.83 A circularloop ofradius 0.3 cmlies parallel toa much bigger circular loop of radius 20 cm.The centreof the small loopisonthe axisofthe

bigger loop. The distancebetween their centreis 15 cm. If a current of 2.0A flows through

thesmallerloop,then thefluxlinkedwith biggerloopis:(1) 6 1011 weber(2) 3.3 1011 weber(3) 6.6 109 weber(4) 9.1 1011 weber

Ans. [4]

Q.84 If a piece of metal is heated to temperature and thenallowed to cool in a roomwhich is attemperature 0, the graph between thetemperature T of the metal and time t will beclosest to

(1)

t

T

0

O

(2)

T

0

O t

(3) 0

O

T

t

(4)

T

O t

Ans. [2]

7/30/2019 Jee Main 2013 Key

13/14

Q.85 The I-V characteristic of an LED is

(1)

I

O V

R

YG

B

(2)

O V

I

(3)

V O

I

R

Y

G

B

(4)I

O V

(R) (Y)(G) (B)R

edY

ellow

Green

Blu

e

Ans. [4]

Q.86 This question hasstatement-Iandstatement-II.Of thefour choices given afterthe statements,choose the one that best describes the twostatements.Statement-I: A point particle of mass mmoving with speed v collides with stationary

point particle of mass M. If the maximum

energy loss possible is given as

2mv2

1f

thenf=

mMm

.

Statement-II: Maximum energy loss occurswhen theparticlesget stucktogetherasa resultofthecollision..(1) Statement-I is true, Statement-II is true,

Statement-II is not a correct explanation ofStatement-I(2) Statement-Iis true, Statement-II is false(3) Statement-Iis false, Statement-II is true(4) Statement-I is true, Statement-II is true,Statement-II is a correct explanation ofStatement-I.

Ans. [3]

Q.87 The amplitudeofa damped oscillatordecreases

to 0.9 times its original magnitude in 5s. Inanother 10 s it will decrease to times itsoriginalmagnitude, whereequals :(1) 0.81 (2) 0.729(3) 0.6 (4) 0.7

Ans. [2]

Q.88 Diameter of a plano - convex lens is 6 cmandthickness at the centre is 3 mm. If speed oflightinmaterialoflensis2108 m/s, thefocallength ofthe lens is

(1) 20 cm (2) 30 cm(3) 10 cm (4) 15 cm

Ans. [2]

7/30/2019 Jee Main 2013 Key

14/14

Q.89 Themagneticfieldinatravellingelectromagneticwave has a peak value of 20 nT. The peakvalueofelectric field strength is :(1) 6 V/m (2) 9 V/m(3) 12 V/m (4) 3 V/m

Ans. [1]

Q.90 Two short bar magnets of length 1 cm eachhave magnetic moments 1.20 Am2 and 1.00Am2 respectively. They are placed on ahorizontaltable parallel to each otherwiththeir

N poles pointing towardstheSouth.Theyhavea common magnetic equator andareseparated

by a distance of 20.0 cm. The value of theresultant horizontal magnetic induction at themid-point O of theline joining their centres isclose to (Horizontal component of earth's

mgnetic induction is 3.6 105 Wb/m2)(1) 2.56 104 Wb/m2

(2) 3.50 104 Wb/m2

(3) 5.80 104 Wb/m2

(4) 3.6 105 Wb/m2

Ans. [1]