IIT JEE 2012 Paper 1 With Solutions

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    IIT-JEE 2012 EXAMINATION

    CODE : 9 08 / 04 / 2012

    Part I : (PHYSICS)

    SECTION I (Single Correct Answer Type)

    This section contains 10 multiple choice questions. Each question has 4 choices (A), (B), (C) and (D), out of which

    ONLY ONE is correct.

    Q.1 A bi-convex lens is formed with two thin plano-convex lenses as shown in the figure. Refractive index n of

    the first lens is 1.5 and that of the second lens is 1.2. Both the curved surfaces are of the same radius of

    curvature R = 14 cm. For this bi-convex lens, for an object distance of 40 cm, the image distance will be

    (A) 280.0 cm (B) 40.0 cm (C) 21.5 cm (D) 13.3 cm

    Ans. [B]

    Sol. For the combination( )

    RRfeq

    )1(11 21 +

    =

    20. =eqf

    Here u = 40, f = 20

    40=v

    Q.2

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    Ans. [B]

    Sol. Angular momentum about rotational axis

    vx

    x = vt L(t) = [I + m(vt)

    2]

    = tmv2dtdL2t ;

    torque = (2mv2)t

    Q.3

    Ans. [C]

    Sol. Under steady state ])T3(T[A]T)T2[(A44

    14

    14 =

    (2T)4

    41T =4

    1T 34T

    4

    2 41T = (24

    + 34)T

    4 ; 2

    41T = (16 + 81)T

    4

    T1 = T2

    974/1

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    Q.4

    Ans. [D]

    Sol.

    O Rr

    E(r)

    r < R ; Er= 0

    r > R ; Er 1/r2

    r < R , V =R

    KQ; r = R , V =

    R

    KQ; r > R , V =

    R

    KQ

    r

    (r)

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    Q.5

    Ans. [A]

    Sol.2d

    MLg4Y

    l= & % ymax = %M + %L + %l + 2%d

    Least count of both instrument, l = d = 3105100

    5.0 =

    %l = %225.0

    105100

    3

    ==

    l

    l

    %11005.0

    105100

    d

    dd%

    3

    =

    =

    =

    here we see that, contribution ofl, = 2%

    contribution of d = 2% d = 2 1 = 2%

    hence both terms l and d contribute equally.

    Q.6

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    Ans. [A]

    Sol.

    4.9 m y = 0 0.2 m

    10 m

    45

    B A

    The block is released from A.

    x = 4.9 m + (0.2 m) sin (t +2

    )

    at t = 15 ; x = 5 m

    So range of projectile will be 5 m

    Nowg

    v =

    90sin5

    2

    v2 = 50

    v = 50

    Q.7

    Ans. [D]

    Sol. As,d

    D=

    R> G > B

    So R> G > B

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    Q.8

    Ans. [C]

    Sol. prL 00rrr

    =

    0Lr

    is always directed along the axis & its magnitude is constant.

    PLr

    P'Lr

    P

    Q.9

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    Ans. [D]

    Sol.m

    KTvrms

    3=

    16.3104

    40

    (Ar)

    (He) ===rms

    rms

    v

    v

    Q.10

    Ans. [C]

    Sol.

    e

    mg

    qE

    45

    qE = mg

    E =q

    mg

    q

    mg

    101

    V2

    =

    19

    312

    106.1

    1001830101.910V

    =

    = 1012

    9.1 114

    = 1000 1012

    V = 1 109

    V

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    SECTION II (Multiple Correct Answer(s) Type)

    This section contains 5 multiple choice questions. Each question has 4 choices (A), (B), (C) and (D), out of which

    ONE or MORE arecorrect.

    Q.11

    Ans. [A, C, D]

    Sol. out =00

    in qq

    =

    By symmetry

    Ans is (A, C, D)

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    Q.12

    Ans. [A,B,C,D]

    Sol. The circuit can be simplified as

    12V

    4 4 4

    2 2 2

    11

    P

    Q T

    S

    because of symmetry no current passes through 1 resistor.

    12V

    4 4 4

    2 2 2P

    Q T

    S

    I1 I1 12V

    12

    6I2

    Req =612

    612

    +

    = 4

    I1 =4

    12= 3A ; I2 = =3

    3

    22A

    Here we have

    4VV QS = i.e., QS VV <

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    Q.13

    Ans. [A, C]

    Sol.

    1N

    1N

    1 cos

    1 sin

    P

    Q

    If = 45 then cos = sin hence block will be at rest.If plane is rough & > 45 then sin > cos so friction will act up the planeIf plane is rough & < 45 then cos > sin so friction will act down the plane so (A, C) are correct

    Q.14

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    Ans. [C, D]

    Sol.

    v

    X

    Y

    E0, B0

    * If = 0 or 10

    then particle moves in helical path with increasing pitch along Y-axis.

    * If = 90 then magnetic force on the particle is zero and particle moves along Y-axis with constantacceleration.

    Q.15 A person blows into open end of a long pipe. As a result, a high pressure pulse of air travels down the pipe.

    When this pulse reaches the other end of the pipe,

    (A) a high pressure pulse starts traveling up the pipe, if the other end of the pipe is open.

    (B) a low pressure pulse starts traveling up the pipe, if the other end of the pipe is open

    (C) a low pressure pulse starts traveling up the pipe, if the other end of the pipe is closed

    (B) a high pressure pulse starts traveling up the pipe, if the other end of the pipe is closed

    Ans. [B, D]

    Sol.

    At rigid end there is no phase difference in pressure wave, when end is open phase difference of come inpressure wave.

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    SECTION III (Integer Answer Type)

    This section contains 5 questions. The answer to each question is a SINGLE DIGIT INTEGER, ranging from 0 to 9

    (both inclusive).

    Q.16

    Ans. [6]

    Sol.

    2

    1

    (1) + (2) = Complete cylinder

    E1 + E2 = E

    E =)R2(2

    R

    0

    2

    =04

    R

    E2 =3

    4

    3

    2

    R

    )R4(4

    12

    0=

    0424

    R

    E1 = E E24

    R

    24

    11 =

    4

    R

    64

    23

    =

    616

    R23

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    Q.17

    Ans. [5]

    Sol.

    OP

    a

    a/2

    I = J a2

    B =

    a2

    aJ 20

    4

    a

    2a32

    J 20

    B = 0Ja

    12

    1

    2

    1

    B = 0Ja 12

    5

    Q.18

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    Ans. [3]

    Sol.

    O

    R

    2R

    P

    Let mass of original disc = m

    The mass of disc removed =)R4(

    m2

    R2 =4

    m

    So M.O.I of remaining section about axis passing

    through "O" I0 =2

    )R2(m 2

    + 2

    2

    R4

    m

    )2(

    R

    4

    m

    2mR2

    +8

    mR2mR 22

    83

    2 mR2

    813

    mR2

    MOI of remaining section about "P"

    IP =

    + 2

    2

    )R2(m2

    )R2(m

    + 2

    2

    R54

    m

    )2(

    R

    4

    m

    [2mR2 + 4mR2]

    +

    4

    mR5

    8

    mR 22

    6mR2 8

    11mR

    2

    8

    37mR

    2

    O

    P

    I

    I=

    8

    37

    13

    8 3

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    Q.19

    Ans. [7]

    Sol. Assume circular wire loop as primary and square loop as secondary coil

    secondary = 2/322

    20

    )RR3(2iR2

    + a2 cos 45

    =2

    2a

    R82

    iR 23

    20

    M =i

    ondarysec=

    R22

    a2/13

    20

    M =

    R2

    a

    2

    7

    20

    Q.20

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    Ans. [7]

    Sol.

    10 fme

    v

    Ui = 0

    Uf= 15

    2

    1010

    e120k

    Ki =2

    mv2

    1and Kf= 0

    From Energy conservation,

    Kf+ Uf= Ki + Ui

    2

    15

    2

    mv2

    1

    1010

    e120K=

    v = 5.76 107

    727

    34

    1076.5103

    5

    1067.6

    mv

    h

    ==

    = 7 fm (approx)

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    Part II : (CHEMISTRY)

    SECTION I SINGLE CORRECT ANSWER TYPE

    This section contains 10 multiple choice questions. Each question has four choices (A), (B), (C) and (D), out of

    which ONLY ONE is correct.

    Q.21 As per IUPAC nomenclature, the name of the complex [Co(H2O)4(NH3)2]Cl3 is -

    (A) Tetraaquadiaminecobalt (III) chloride

    (B) Tetraaquadiamminecobalt (III) chloride

    (C) Diaminetetraaquacobalt (III) chloride

    (D) Diamminetetraaquacobalt (III) chloride

    Ans. [D]

    Sol. Factual

    Q.22 In allene (C3H4), the type (s) of hybridization of the carbon atoms is (are)(A) sp and sp

    3(B) sp and sp

    2(C) only sp

    2(D) sp

    2and sp

    3

    Ans. [B]

    Sol. CH2=C=CH2

    sp2

    spsp

    2

    Q.23 For one mole of a van der Waals gas when b = 0 and T= 300 K, the PVvs. 1/Vplot is shown below. The

    value of the van der Waals constant a (atm. liter2 mol2)

    20.1

    3.00

    21.6

    24.6

    23.1

    2.0

    PV(liter-atmm

    ol1)

    V

    1(mol liter

    1)

    [Graph not to scale ]

    (A) 1.0 (B) 4.5 (C) 1.5 (D) 3.0

    Ans. [C]

    Sol.

    +

    2V

    aP V = RT

    PV = RT V

    a

    Slope = a

    =1

    6.211.20= 1.5

    a = 1.5

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    Q.24 The number of optically active products obtained from the complete ozonolysis of the given compound is

    CH3CH=CHCCH=CHCCH=CHCH3

    CH3 H

    H CH3 (A) 0 (B) 1 (C) 2 (D) 4

    Ans. [A]

    Sol. CH3CH=CHCCH=CHCCH=CHCH3O3, Zn, H2O

    O O O O OO

    CH3

    H

    H

    CH3

    2CH3.CHO + OHCCCHO + OHCCCHO

    CH3

    H

    H

    CH3

    Q.25 A compound MpXq has cubic close packing (ccp) arrangement of X. Its unit cell structure is shown below.

    The empirical formula of the compound is -

    (A) MX (B) MX2 (C) M2X (D) M5X14

    Ans. [B]

    Sol.

    8

    18

    X

    + 6 2

    1= X4

    4

    14

    M

    + 1 = M2

    Simplest ration = X2M

    Q.26 The number of aldol reaction (s) that occurs in the given transformation is -

    (A) 1 (B) 2 (C) 3 (D) 4Ans. [C]

    Sol. CH3CHO + 3HCHO

    nrexaldol3

    NaOH.aq

    .conc HOCH2CCHO + HCHO

    CH2OH

    CH2OH

    nrex

    Cannizaro HOCH2CCH2OH + HCOONa

    CH2OH

    CH2OH

    Q.27 The colour of light absorbed by an aqueous solution of CuSO4 is -

    (A) orange-red (B) blue-green (C) yellow (D) violet

    Ans. [A]

    Sol. Factual.

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    Q.28 The carboxyl functional group (COOH) is present in -

    (A) picric acid (B) barbituric acid (C) ascorbic acid (D) aspirin

    Ans. [D]

    Sol.

    OCOCH3

    COOH

    Aspirin

    Q.29 The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is [a0 is Bohr radius]

    (A)20

    2

    2

    4

    h

    ma(B)

    20

    2

    2

    16

    h

    ma(C)

    20

    2

    2

    32

    h

    ma(D)

    20

    2

    2

    64

    h

    ma

    Ans. [C]

    Sol. mvr =2

    nh

    mv =r2

    nh

    m2v

    2=

    22

    22

    r4

    hn

    2

    1m

    2v

    2=

    22

    22

    r8

    hn

    2

    1

    m

    vm 22= K.E =

    20

    22

    2

    22

    z

    nm8

    hn

    a

    =20

    22

    2

    nm8

    h

    a

    ==

    1z2n

    =20

    2

    2

    32

    h

    ma

    Q.30 Which ordering of compounds is according to the decreasing order of the oxidation state of nitrogen ?

    (A) HNO3, NO, NH4Cl, N2 (B) HNO3, NO, N2, NH4Cl

    (C) HNO3, NH4Cl, NO, N2 (D) NO, HNO3, NH4Cl, N2

    Ans. [B]

    Sol. 3

    5

    ONH

    +

    ON

    2+

    2

    0

    N ClHN 4

    3

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    SECTION II : MULTIPLE CORRECT ANSWER(S) TYPE

    This section contains 5 multiple choice questions. Each question has four choices (A), (B), (C) and (D), out of which

    ONE or MORE are correct.

    Q.31 Identify the binary mixture(s) that can be separated into individual compounds, by differential extraction, as

    shown in the given scheme.

    (A) C6H5OH and C6H5COOH (B) C6H5COOH and C6H5CH2OH

    (C) C6H5CH2OH and C6H5OH (D) C6H5CH2OH and C6H5CH2COOHAns. [B,D]

    Sol. Factual

    Q.32 Choose the correct reason(s) for the stability of the lyophobic colloidal particles.

    (A) Preferential adsorption of ions of on their surface from the solution

    (B) Preferential adsorption of solvent on their surface from the solution

    (C) Attraction between different particles having opposite charges on their surface

    (D) Potential difference between the fixed layer and the diffused layer of opposite charges around the

    colloidal particles

    Ans. [A,D]Sol. Factual.

    Q.33 Which of the following molecules, in pure form, is (are) unstable at room temperature ?

    (A) (B) (C)

    O

    (D)

    O

    Ans. [B,C]

    Sol. Antiaromaticity

    Q.34 Which of the following hydrogen halides react(s) with AgNO3(aq) to give a precipitate that dissolves in

    Na2S2O3(aq) ?

    (A) HCl (B) HF (C) HBr (D) HI

    Ans. [A,C,D]

    Sol. AgBr + 2Na2S2O3 Na3[Ag(S2O3)2] + NaBr

    Sodium argentothio sulphate

    colourless soluble

    Similar reaction observed in AgCl, AgI

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    Q.35 For an ideal gas, consider onlyP-Vwork in going from an initial state Xto the final stateZ. The final stateZ

    can be reached by either of the two paths shown in the figure. Which of the following choices(s) is (are)

    correct ? [take Sas change in entropy and w as work done]

    (A) Sxz = Sxy + Sy z (B) Wxz = Wxy + Wy z

    (C) Wxyz = Wxy (D) Sxyz = SxyAns. [A,C]

    Sol. Sx z = Sx y + Sy zState

    Wx y z = Wx y + Wy z 0

    SECTION III : INTEGER ANSWER TYPE

    This section contains 5 questions. The answer to each question is a single digit integer, ranging from 0 to 9 (both

    inclusive)

    Q.36 The substituents R1 and R2 for nine peptides are listed in the table given below. How many of these peptides

    are positively charged at pH = 7.0 ?

    H3NCHCONHCHCONHCHCONHCHCOO

    H R1 R2 H

    Peptide R1 R2

    I H H

    II H CH3

    III CH2COOH H

    IV CH2CONH2 (CH2)4NH2

    V CH2CONH2 CH2CONH2

    VI (CH2)4NH2 (CH2)4NH2VII CH2 COOH CH2CONH2

    VIII CH2 OH (CH2)4NH2

    IX (CH2)4 NH2 CH3

    Ans. [4]

    Sol. IV, VI, VIII, IX

    Four amides are positively charged at pH = 7.0

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    Q.37 The periodic table consists of 18 groups. An isotope of copper, on bombardment with protons, undergoes a

    nuclear reaction yielding element X as shown below. To which group, element X belongs in the periodic

    table ?

    X++++ H2n6HCu1

    1

    1

    0

    1

    1

    63

    29 Ans. [8]

    Sol. Z = 29 + 1 2 2 = 26

    Fe 8th groups.

    Q.38 When the following aldohexose exists in its D-configuration, the total number of stereoisomers in its

    pyranose form is -

    CHO

    CH2

    CHOHCHOH

    CHOH

    CH2OH

    Ans. [8]

    Sol. 8 stereoisomers possible for given compound in pyranose form of D-configuration.

    Q.39 29.2% (w/w) HCl stock solution has a density of 1.25 g mL1

    . The molecular weight of HCl is 36.5 g mol1

    .

    The volume (mL) of stock solution required to prepare a 200 mL solution of 0.4 M HCl is.Ans. [8]

    Sol.wt.mol

    10dx V = 200 0.4

    5.36

    V1025.12.29 = 200 0.4

    V = 8 ml.

    Q.40 An organic compound undergoes first-order decomposition. The time taken for its decomposition to 1/8 and

    1/10 of its initial concentration are t1/8 and t1/10 respectively. What is the value of]t[]t[

    10/1

    8/1 10 ? (take log102 = 0.3)

    Ans. [9]

    Sol. =10t

    t

    10/1

    8/1

    10/a

    alog

    K

    303.2

    8/a

    alog

    K

    303.2

    10 = 9

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    Part III : (MATHEMATICS)

    SECTION I (Single Correct Answer Type)

    This section contains 10 multiple choice questions. Each question has 4 choices (A), (B), (C) and (D), out of whichONLY ONE is correct.

    Q.41 The locus of the mid-point of the chord of contact of tangents drawn from points lying on the straight line

    4x 5y = 20 to the circle x2

    + y2

    = 9 is

    (A) 20(x2

    + y2) 36x + 45y = 0 (B) 20(x

    2+ y

    2) + 36x 45y = 0

    (C) 36(x2

    + y2) 20x + 45y = 0 (D) 36(x

    2+ y

    2) + 20x 45y = 0

    Ans. [A]

    Sol.

    x2 + y2 = 9(h, k)P

    5

    204,

    4x 5y = 20

    A

    B

    Equation of chord AB is T = 0

    x +

    5

    204y = 9 (i)

    & hx + ky 9 = h2

    + k2

    9 (ii)

    Q Equation (i) & (ii) both represent the same line

    Soh

    =

    k

    5

    204

    =22 kh

    9

    +

    =22 kh

    h9

    +=

    )kh(4

    )kh(20k4522

    22

    +

    ++

    36h = 45k + 20(h2

    + k2)

    20(x2

    + y2) 36x + 45y = 0

    Q.42 The total number of ways in which 5 balls of different colours can be distributed among 3 persons so that

    each person gets at least one ball is

    (A) 75 (B) 150 (C) 210 (D) 243Ans. [B]

    Sol. G1 G2 G3

    1 1 3

    1 2 2

    +

    !2!2!2!1

    !5

    !2!3!1!1

    !53!

    = 150

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    Q.43 Let f(x) =

    =

    0x,0

    0x,x

    cosx2, x IR,

    then f is(A) differentiable both at x = 0 and at x = 2

    (B) differentiable at x = 0 but not differentiable at x = 2

    (C) not differentiable at x = 0 but differentiable at x = 2

    (D) differentiable neither at x = 0 nor at x = 2

    Ans. [B]

    Sol. f(0 + h) =0h

    lim

    0h

    0h

    cosh2

    = 0

    f(0 h) =0h

    lim h

    0h

    cosh2

    = 0

    Q f(0+) = f(0) = 0 = finite

    So f(x) is differentiable at x = 0

    f(2 + h) =0h

    lim

    h

    0h2

    cos)h2( 2

    +

    +

    =

    f(2 h) =0h

    lim h

    0h2cos)h2(2

    =

    Qf(2+) f(2) but both are finite so f(x) is not differentiable at x = 2 but continuous at x = 2

    Q.44 The function f : [0, 3] [1, 29], defined by f(x) = 2x3 15x2 + 36x + 1, is

    (A) one-one and onto. (B) onto but not one-one.

    (C) one-one but not onto. (D) neither one-one nor onto.

    Ans. [B]

    Sol. Given f : [0, 3] [1, 29]f(x) = 2x3 15x2 + 36x + 1

    f'(x) = 6x2 30x + 36

    = 6(x 2) (x 3)

    f'(x) > 0 if x(0, 2)& f '(x) < 0 if x(2, 3) Function is many one & continuousNow f(0) = 1

    f(2) = 29

    Range = co-domain

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    0 2 3

    (2,29)

    (3,28)

    (0,1)

    Hence function is onto.

    Q.45 If

    +++

    bax

    1x

    1xxlim

    2

    x= 4, then

    (A) a = 1, b = 4 (B) a = 1, b = 4 (C) a = 2, b = 3 (D) a = 2, b = 3

    Ans. [B]

    Sol. xlim

    +++

    1x

    bbxaxax1xx 22

    = 4

    xlim

    +++

    1x

    b1)ba1(x)a1(x 2= 4

    As limit is finite so 1 a = 0

    a = 1

    Nowx

    lim

    +

    +

    x

    11

    x

    b1)ba1(

    = 4

    1 a b = 4

    as a = 1 b = 4

    Q.46 Let z be a complex number such that the imaginary part of z is nonzero and a = z 2 + z + 1 is real. Then a

    cannot take the value

    (A) 1 (B)3

    1(C)

    2

    1(D)

    4

    3

    Ans. [D]

    Sol. As a is real

    So a = a

    z2 + z + 1 = 2z + z + 1

    (z z ) (z + z +1) = 0

    As z is imaginary

    So z z 0

    z + z + 1 = 0

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    z + z = 1 z = x + iy

    x =2

    1

    so a = (x + iy)

    2

    + (x + iy) + 1

    = (x2 + x + 1 y2) + (2x + 1)yi x = 2

    1

    a =4

    3 y2

    so a 0

    So a 4

    3

    Q.47 The ellipse E1 :4y

    9x 22 + = 1 is inscribed in a rectangle R whose sides are parallel to the coordinate axes.

    Another ellipse E2 passing through the point (0, 4) circumscribes the rectangle R. The eccentricity of the

    ellipse E2 is

    (A)2

    2(B)

    2

    3(C)

    2

    1(D)

    4

    3

    Ans. [C]

    Sol.

    (0, 4)

    (0, 2) (3, 2)

    (3, 0)

    (0,2)

    (3,0)

    Let equation of ellipse E2 is

    1b

    y

    a

    x2

    2

    2

    2=+

    it passes through (0, 4)

    so b2 = 16

    and also passes through (3, 2)

    So 1b

    4

    a

    922

    =+ 14

    1

    a

    92

    =+ a2 = 12

    as a < bso 12 = 16 (1 e

    2)

    e2 =4

    1 e =

    2

    1

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    Q.48 Let P = [aij]be a 3 3 matrix and let Q = [b ij], where bij = 2i + j

    aij for 1 i, j 3, If the determinant of P is 2,then the determinant of the matrix Q is

    (A) 210

    (B) 211

    (C) 212

    (D) 213

    Ans. [D]

    Sol. Let P =

    333231

    232221

    131211

    aaa

    aaaaaa

    So Q =

    336

    325

    314

    235

    224

    213

    134

    123

    112

    a2a2a2

    a2a2a2

    a2a2a2

    Now det (Q) = 222

    32

    4

    332

    322

    312

    232221

    131211

    a2a2a2

    a2a2a2

    aaa

    = 29

    2 22

    333231

    232221

    131211

    aaa

    aaa

    aaa

    = 212

    det (P)

    = 212

    2 = 213

    Ans. [C]

    Sol. I = + dx)xtanx(secxsec

    2/9

    2

    sex x + tan x = t

    (sec x tan x + sec2 x) dx = dt

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    sec x dx =t

    dt

    also, sec x tan x =t

    1

    sec x =2

    1

    +t

    1t

    So, I =

    +

    2/11t

    dtt

    1t

    2

    1

    =

    + dtt

    1

    t

    1

    2

    12/132/9

    = K

    t

    1

    11

    2

    t

    1

    7

    2

    2

    12/112/7

    +

    = K11

    1

    7

    t

    t

    1 2

    2/11+

    +

    =

    +++

    11

    1)xtanx(sec

    7

    1

    )xtanx(sec

    1 22/11

    + K

    Ans. [A]

    Sol. Equation of line

    =

    =

    =

    1

    5z

    4

    3y

    1

    2x

    General points { + 2, 4 + 3, + 5}

    Intersection point with plane

    5( + 2) 4(4 + 3) ( + 5) = 1

    5 + 10 16 12 5 = 1

    12 8 = 0

    = 12

    8=

    3

    2

    Point

    +

    ++

    5

    3

    2,3

    3

    8,2

    3

    2

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    P

    3

    13,

    3

    1,

    3

    4

    T(2, 1, 4)

    Dr's( , 4 + 2, + 1)

    S( +2, 4 + 3, + 5)Dr's(1, 4, 1)

    Now

    + 4 (4 + 2) + ( + 1) = 0

    + 16 + 8 + + 1 = 0

    18 = 9

    = 2

    1

    Points

    +++

    5

    2

    1,32,2

    2

    1

    2

    9,1,

    2

    3

    Distance at PS =

    222

    2

    9

    3

    131

    3

    1

    2

    3

    3

    4

    +

    +

    PS =36

    1

    9

    4

    36

    1++ =

    36

    1161 ++=

    36

    18=

    2

    1

    SECTION II (Multiple Correct Answer(s) Type)

    This section contains 5 multiple choice questions. Each question has four choices (A), (B), (C) and (D), out of which

    ONE or MORE are correct.

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    Ans. [A, C, D]

    Sol. tan (2 ) > 0

    0 < 2 2

    1ve ; x <

    2

    1+ve

    x 1 f(x) = x2

    x 1 f '(x) = 2x 1 ve

    11/2 0 1/2 1

    Ans. [4]

    Sol. Let x = ...23

    14

    23

    14

    23

    14

    x2

    = 4 23

    1x

    23 x2

    + x 12 2 = 0

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    x =26

    212.23.411 ++

    x =26

    171+=

    23

    8

    6 + log3/2

    9

    4= 6 + log3./2

    2

    2

    3

    = 6 2 = 4

    Ans. [9]

    Sol. P'(1) = 0, P'(3) = 0

    P'(x) = K(x 1) (x 3)

    = K(x2

    4 x + 3) P'(0) = 3K

    P(x) =3

    Kx

    3 2K x

    2+ 3K x +

    3

    K 2K + 3K + = 6, 9K 18 K + 9K + = 2

    34 K + = 6,

    34 K = 4

    K = 3

    P'(0) = 9

    Ans. [3]

    Sol.2|ba|

    rr + 2|cb|

    rr + 2|ac|

    rr = 9

    a.b + b.c + c.a = 3/2 ....(1)

    Q2|cba|

    rrr++ 0 ....(2)

    a.b + b.c + c.a 2

    3....(3)

    Q from (1) & (3)

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    so |cba|rrr

    ++ = 0

    cbarrr

    ++ = 0

    cbarrr

    =

    on squaring

    1 = 2 + 2 cos B

    cos B = 2

    1 B = b

    r^ cr

    .

    Let T = |2 ar

    + 5br

    + 5 cr

    |

    = |3 br

    + 3 cr

    |

    = |cb|3rr

    +

    = Bcos223 +

    = 3

    Ans. [4]

    Sol. (x 1)2

    + (y 2)2

    = ( 5 )2

    (2, 0)

    y

    SQ

    P (2, 4)

    y2

    = 8x

    x

    2+ 8x 2x 4.2 x2 = 0

    x2

    + 6x 8 x2 = 0

    x3/2

    + 6x1/2

    28 = 0

    x1/2

    = t

    t3 + 6t 28 = 0

    (t 2 ) (t2

    2 t + 4) = 0

    t = 2 x = 2

    y = 4

    P(2, 4) Q(0, 0) S(2, 0)

    Area PQS =2

    1 2 4 = 4