Paper - 2: Read The Instructions Carefully

JEE Advanced 2015 - Paper 2 MathonGo
CODE 4 PAPER -2
Time : 3 Hours Maximum Marks : 240
READ THE INSTRUCTIONS CAREFULLY

QUESTION PAPER FORMAT AND MARKING SCHEME :
1. The question paper has three parts: Physics, Chemistry and Mathematics. Each part has three sections.
2. Section 1 contains 8 questions. The answer to each question is a single digit integer ranging from
0 to 9 (both inclusive).
Marking Scheme: +4 for correct answer and 0 in all other cases.
3. Section 2 contains 8 multiple choice questions with one or more than one correct option.
Marking Scheme: +4 for correct answer, 0 if not attempted and –2 in all other cases.
4. Section 3 contains 2 “paragraph” type questions. Each paragraph describes an experiment, a situation or a
problem. Two multiple choice questions will be asked based on this paragraph. One or more than one
option can be correct.
Marking Scheme: +4 for correct answer, 0 if not attempted and – 2 in all other cases.
For more such free study materials, visit www.mathongo.com

PART-I: PHYSICS
Section 1 (Maximum Marks: 32)

 This section contains EIGHT questions.
 The answer to each question is a SINGLE DIGIT INTEGER ranging from 0 to 9, both inclusive.
 For each question, darken the bubble corresponding to the correct integer in the ORS.
 Marking scheme:
+4 If the bubble corresponding to the answer is darkened.
0 In all other cases.
1. An electron in an excited state of Li2+ ion has angular momentum 3h/2. The de Broglie wavelength of the
electron in this state is pa0 (where a0 is the Bohr radius). The value of p is
*2. A large spherical mass M is fixed at one position and two identical point masses m are kept on a line
passing through the centre of M (see figure). The point masses are connected by a rigid massless rod of
length  and this assembly is free to move along the line connecting them. All three masses interact only
through their mutual gravitational interaction. When the point mass nearer to M is at a distance r = 3 from
 M 
M, the tension in the rod is zero for m = k   . The value of k is
 288 
M m m
r 
3. The energy of a system as a function of time t is given as E(t) = A2exp(t), where  = 0.2 s1. The
measurement of A has an error of 1.25 %. If the error in the measurement of time is 1.50 %, the percentage
error in the value of E(t) at t = 5 s is
*4. The densities of two solid spheres A and B of the same radii R vary with radial distance r as A(r) =
5
 r  r 
k   and B(r) = k   , respectively, where k is a constant. The moments of inertia of the individual
R R
I n
spheres about axes passing through their centres are IA and IB, respectively. If B  , the value of n is
IA 10
*5. Four harmonic waves of equal frequencies and equal intensities I0 have phase angles 0, /3, 2/3 and .
When they are superposed, the intensity of the resulting wave is nI0. The value of n is
dN
6. For a radioactive material, its activity A and rate of change of its activity R are defined as A =  and
dt
dA
R=  , where N(t) is the number of nuclei at time t. Two radioactive sources P (mean life ) and
dt
Q(mean life 2) have the same activity at t = 0. Their rates of change of activities at t = 2 are RP and RQ,
R n
respectively. If P  , then the value of n is
RQ e

7. A monochromatic beam of light is incident at 600 on one

face of an equilateral prism of refractive index n and
emerges from the opposite face making an angle (n) 
600
with the normal (see the figure). For n = 3 the value of
d
 is 600 and  m . The value of m is
dn
8. In the following circuit, the current through the resistor R (=2) is I Amperes. The value of I is
R (=2) 1
2 8
2
6
4
6.5V
10
12 4

 Each question has FOUR options (A), (B), (C) and (D). ONE OR MORE THAN ONE of these four
option(s) is(are) correct.
 For each question, darken the bubble(s) corresponding to all the correct option(s) in the ORS.
 Marking scheme:
+4 If only the bubble(s) corresponding to all the correct option(s) is(are) darkened.
0 If none of the bubbles is darkened
2 In all other cases
236
9. A fission reaction is given by 92 U  140 94
54 Xe  38 Sr  x  y , where x and y are two particles. Considering
236
92 U to be at rest, the kinetic energies of the products are denoted by KXe, KSr, Kx(2MeV) and Ky(2MeV),
respectively. Let the binding energies per nucleon of 236 140 94
92 U , 54 Xe and 38 Sr be 7.5 MeV, 8.5 MeV and
8.5 MeV respectively. Considering different conservation laws, the correct option(s) is(are)
(A) x = n, y = n, KSr = 129MeV, KXe = 86 MeV
(B) x = p, y = e-, KSr = 129 MeV, KXe = 86 MeV
(C) x = p, y = n, KSr = 129 MeV, KXe = 86 MeV
(D) x = n, y = n, KSr = 86 MeV, KXe = 129 MeV

*10. Two spheres P and Q of equal radii have densities 1 and 2,
respectively. The spheres are connected by a massless string and L1
placed in liquids L1 and L2 of densities 1 and 2 and viscosities 1 and P
2, respectively. They float in equilibrium with the sphere P in L1 and
sphere Q in L2 and the string being taut (see figure). If sphere P alone in L2
  Q
L2 has terminal velocity VP and Q alone in L1 has terminal velocity VQ ,
then
 
VP VP
1 2
(A) 
 (B) 

2 1
VQ VQ
   
(C) VP .VQ  0 (D) VP .VQ  0
11. In terms of potential difference V, electric current I, permittivity 0, permeability 0 and speed of light c,
the dimensionally correct equation(s) is(are)
(A)  0 I2  0 V 2 (B)  0 I  0 V
(C) I  0 cV (D)  0 cI   0 V
12. Consider a uniform spherical charge distribution R2

of radius R1 centred at the origin O. In this P
distribution, a spherical cavity of radius R2, a
R1
centred at P with distance OP = a = R1 – R2 (see
O
figure) is made. If the electric field inside the
  
cavity at position r is E(r), then the correct
statement(s) is(are)
 
(A) E is uniform, its magnitude is independent of R2 but its direction depends on r
 
(B) E is uniform, its magnitude depends on R2 and its direction depends on r
 
(C) E is uniform, its magnitude is independent of a but its direction depends on a
 
(D) E is uniform and both its magnitude and direction depend on a
*13. In plotting stress versus strain curves for two materials P

and Q, a student by mistake puts strain on the y-axis and
stress on the x-axis as shown in the figure. Then the
correct statement(s) is(are) Strain P
(A) P has more tensile strength than Q Q
(B) P is more ductile than Q
(C) P is more brittle than Q
(D) The Young’s modulus of P is more than that of Q Stress
*14. A spherical body of radius R consists of a fluid of constant density and is in equilibrium under its own
gravity. If P(r) is the pressure at r(r < R), then the correct option(s) is(are)
P(r  3R / 4) 63
(A) P(r = 0) = 0 (B) 
P(r  2R / 3) 80
P(r  3R / 5) 16 P(r  R / 2) 20
(C)  (D) 
P(r  2R / 5) 21 P(r  R / 3) 27

15. A parallel plate capacitor having plates of area S and plate separation d, has capacitance C1 in air. When
two dielectrics of different relative permittivities (1 = 2 and 2 = 4) are introduced between the two plates
C
as shown in the figure, the capacitance becomes C2. The ratio 2 is
C1
d/2
S/2
2
S/2 –
+
1
d
(A) 6/5 (B) 5/3
(C) 7/5 (D) 7/3
*16. An ideal monoatomic gas is confined in a horizontal

cylinder by a spring loaded piston (as shown in the
figure). Initially the gas is at temperature T1, pressure
P1 and volume V1 and the spring is in its relaxed state.
The gas is then heated very slowly to temperature T2,
pressure P2 and volume V2. During this process the
piston moves out by a distance x. Ignoring the friction
between the piston and the cylinder, the correct
1
(A) If V2 = 2V1 and T2 = 3T1, then the energy stored in the spring is P1V1
4
(B) If V2 = 2V1 and T2 = 3T1, then the change in internal energy is 3P1V1
7
(C) If V2 = 3V1 and T2 = 4T1, then the work done by the gas is P1V1
3
17
(D) If V2 = 3V1 and T2 = 4T1, then the heat supplied to the gas is P1V1
6
SECTION 3 (Maximum Marks: 16)
 This section contains TWO paragraphs

 Based on each paragraph, there will be TWO questions
option(s) is(are) correct
 For each question, darken the bubble(s) corresponding to all the correct option(s) in the ORS
 Marking scheme:
+4 If only the bubble(s) corresponding to all the correct option(s) is(are) darkened
–2 In all other cases

PARAGRAPH 1
Light guidance in an optical fiber can be understood by considering a structure comprising of thin solid glass
cylinder of refractive index n 1 surrounded by a medium of lower refractive index n2. The light guidance in the
structure takes place due to successive total internal reflections at the interface of the media n1 and n2 as shown in
the figure. All rays with the angle of incidence i less than a particular value im are confined in the medium of
refractive index n1. The numerical aperture (NA) of the structure is defined as sin im.
n1  n 2
Air n2
Cladding
 Core
i n1
17. For two structures namely S1 with n1  45 / 4 and n 2  3 / 2, and S2 with n1 = 8/5 and n2 = 7/5 and
taking the refractive index of water to be 4/3 and that of air to be 1, the correct option(s) is(are)
16
(A) NA of S1 immersed in water is the same as that of S2 immersed in a liquid of refractive index
3 15
6
(B) NA of S1 immersed in liquid of refractive index is the same as that of S2 immersed in water
15
4
(C) NA of S1 placed in air is the same as that of S2 immersed in liquid of refractive index .
15
(D) NA of S1 placed in air is the same as that of S2 placed in water
18. If two structures of same cross-sectional area, but different numerical apertures NA1 and
NA 2 (NA 2  NA1 ) are joined longitudinally, the numerical aperture of the combined structure is
NA1 NA 2
(A) (B) NA1 + NA2
NA1  NA 2
(C) NA1 (D) NA2
PARAGRAPH 2
In a thin rectangular metallic strip a constant current I flows along the positive x-direction, as shown in the figure.

The length, width and thickness of the strip are  , w and d, respectively. A uniform magnetic field B is applied on
the strip along the positive y-direction. Due to this, the charge carriers experience a net deflection along the z-
direction. This results in accumulation of charge carriers on the surface PQRS and appearance of equal and opposite
charges on the face opposite to PQRS. A potential difference along the z-direction is thus developed. Charge
accumulation continues until the magnetic force is balanced by the electric force. The current is assumed to be
uniformly distributed on the cross section of the strip and carried by electrons.

l
y
K
I I
W x
R
S
d M
z
P Q
19. Consider two different metallic strips (1 and 2) of the same material. Their lengths are the same, widths are
w1 and w2 and thicknesses are d1 and d2, respectively. Two points K and M are symmetrically located on
the opposite faces parallel to the x-y plane (see figure). V1 and V2 are the potential differences between K
and M in strips 1 and 2, respectively. Then, for a given current I flowing through them in a given magnetic
field strength B, the correct statement(s) is(are)
(A) If w1 = w2 and d1 = 2d2, then V2 = 2V1 (B) If w1 = w2 and d1 = 2d2, then V2 = V1
(C) If w1 = 2w2 and d1 = d2, then V2 = 2V1 (D) If w1 = 2w2 and d1 = d2, then V2 = V1
20. Consider two different metallic strips (1 and 2) of same dimensions (lengths  , width w and thickness d)
with carrier densities n1 and n2, respectively. Strip 1 is placed in magnetic field B1 and strip 2 is placed in
magnetic field B2, both along positive y-directions. Then V1 and V2 are the potential differences developed
between K and M in strips 1 and 2, respectively. Assuming that the current I is the same for both the strips,
the correct option(s) is(are)
(A) If B1 = B2 and n1 = 2n2, then V2 = 2V1 (B) If B1 = B2 and n1 = 2n2, then V2 = V1
(C) If B1 = 2B2 and n1 = n2, then V2 = 0.5V1 (D) If B1 = 2B2 and n1 = n2, then V2 = V1

PART-II: CHEMISTRY
 This section contains EIGHT questions

 The answer to each question is a SINGLE DIGIT INTEGER ranging from 0 to 9, both inclusive
 For each question, darken the bubble corresponding to the correct integer in the ORS
 Marking scheme:
+4 If the bubble corresponding to the answer is darkened
0 In all other cases
*21. In dilute aqueous H2SO4, the complex diaquodioxalatoferrate(II) is oxidized by MnO4. For this reaction,
the ratio of the rate of change of [H+] to the rate of change of [MnO4] is
*22. The number of hydroxyl group(s) in Q is
H aqueous dilute KMnO (excess)

H  
heat
 P 
0ºC
4
Q
HO
H3C CH3
23. Among the following, the number of reaction(s) that produce(s) benzaldehyde is
CO, HCl
I 
Anhydrous AlCl /CuCl

3
CHCl 2
2 H O
II 
100ºC

COCl
2 H
III 
Pd  BaSO

4
CO2 Me
DIBAL  H
IV 
Toluene,  78º C

H 2O
24. In the complex acetylbromidodicarbonylbis(triethylphosphine)iron(II), the number of Fe–C bond(s) is
25. Among the complex ions, [Co(NH2-CH2-CH2-NH2)2Cl2]+, [CrCl2(C2O4)2]3–, [Fe(H2O)4(OH)2]+,

[Fe(NH3)2(CN)4], [Co(NH2-CH2-CH2-NH2)2(NH3)Cl]2+ and [Co(NH3)4(H2O)Cl]2+, the number of complex
ion(s) that show(s) cis-trans isomerism is
*26. Three moles of B2H6 are completely reacted with methanol. The number of moles of boron containing
product formed is
27. The molar conductivity of a solution of a weak acid HX (0.01 M) is 10 times smaller than the molar
conductivity of a solution of a weak acid HY (0.10 M). If  0X    0Y , the difference in their pKa values,
pK a (HX)  pK a (HY), is (consider degree of ionization of both acids to be << 1)

238
28. A closed vessel with rigid walls contains 1 mol of 92 U and 1 mol of air at 298 K. Considering complete
238 206
decay of 92 U to 82 Pb , the ratio of the final pressure to the initial pressure of the system at 298 K is
 This section contains EIGHT questions

 Marking scheme:
*29. One mole of a monoatomic real gas satisfies the equation p(V – b) = RT where b is a constant. The
relationship of interatomic potential V(r) and interatomic distance r for the gas is given by
V(r) V(r)
(A) 0 (B) 0
r r
V(r) V(r)
(C) 0 (D) 0
r r
30. In the following reactions, the product S is

H3C
i. O 3 NH
3

ii. Zn, H O
 R  S
2
H3C H3C N
N
(A) (B)
N
N
(C) (D)
H3C H3C

31. The major product U in the following reactions is
CH CH  CH , H
2 3 radical initiator, O
2

high pressure, heat
 T  U
H H3 C CH3
O
O O H
(A) O (B)
CH3
H CH2
O O H
(C) O (D) O
CH2
32. In the following reactions, the major product W is

OH
NH2
, NaOH
NaNO , HCl
2

0ºC
 V 
W
OH
(A) (B)
N N OH N N
HO
OH
(C) (D)
N N N N
*33. The correct statement(s) regarding, (i) HClO, (ii) HClO2, (iii) HClO3 and (iv) HClO4, is (are)
(A) The number of Cl = O bonds in (ii) and (iii) together is two
(B) The number of lone pairs of electrons on Cl in (ii) and (iii) together is three
(C) The hybridization of Cl in (iv) is sp3
(D) Amongst (i) to (iv), the strongest acid is (i)

34. The pair(s) of ions where BOTH the ions are precipitated upon passing H2S gas in presence of dilute HCl,
is(are)
(A) Ba2+, Zn2+ (B) Bi3+, Fe3+
2+ 2+
(C) Cu , Pb (D) Hg2+, Bi3+
*35. Under hydrolytic conditions, the compounds used for preparation of linear polymer and for chain
termination, respectively, are
(A) CH3SiCl3 and Si(CH3)4 (B) (CH3)2SiCl2 and (CH3)3SiCl
(C) (CH3)2SiCl2 and CH3SiCl3 (D) SiCl4 and (CH3)3SiCl
36. When O2 is adsorbed on a metallic surface, electron transfer occurs from the metal to O2. The TRUE
statement(s) regarding this adsorption is(are)
(A) O2 is physisorbed (B) heat is released
*
(C) occupancy of 2p of O2 is increased (D) bond length of O2 is increased
 This section contains TWO paragraphs

 Marking scheme:
0 In none of the bubbles is darkened
PARAGRAPH 1
When 100 mL of 1.0 M HCl was mixed with 100 mL of 1.0 M NaOH in an insulated beaker at constant pressure, a
temperature increase of 5.7oC was measured for the beaker and its contents (Expt. 1). Because the enthalpy of
neutralization of a strong acid with a strong base is a constant (57.0 kJ mol-1), this experiment could be used to
measure the calorimeter constant. In a second experiment (Expt. 2), 100 mL of 2.0 M acetic acid (Ka = 2.0 × 10-5)
was mixed with 100 mL of 1.0 M NaOH (under identical conditions to Expt. 1) where a temperature rise of 5.6oC
was measured.
(Consider heat capacity of all solutions as 4.2 J g-1 K-1 and density of all solutions as 1.0 g mL-1)
*37. Enthalpy of dissociation (in kJ mol-1) of acetic acid obtained from the Expt. 2 is
(A) 1.0 (B) 10.0
(C) 24.5 (D) 51.4
*38. The pH of the solution after Expt. 2 is

(A) 2.8 (B) 4.7
(C) 5.0 (D) 7.0
PARAGRAPH 2
In the following reactions
4 Pd-BaSO 2 6 i. B H
C8 H 6 
H
 C8 H 8 
ii. H O , NaOH, H O
X
2 2 2 2
H2 O
HgSO 4 , H 2SO 4
i. EtMgBr, H O
2
C8 H 8O 
ii. H  , heat
Y

39. Compound X is
O OH
(A) CH3 (B) CH3
OH
CHO
(C) (D)
40. The major compound Y is
CH3 CH3
(A) (B)
CH2 CH3
CH3
(C) (D) CH3

PART-III: MATHEMATICS
 The answer to each question is a SINGLE DIGIT INTEGER ranging from 0 to 9, both inclusive.
 For each question, darken the bubble corresponding to the correct integer in the ORS.
 Marking scheme:
+4 If the bubble corresponding to the answer is darkened.
0 In all other cases.
   
41. Suppose that p, q and r are three non-coplanar vectors in R3. Let the components of a vector s along
         
p, q and r be 4, 3 and 5, respectively. If the components of this vector s along   p  q  r  ,  p  q  r 
  
and   p  q  r  are x, y and z, respectively, then the value of 2x + y + z is
 k   k 
*42. For any integer k, let k = cos    i sin   , where i = 1 . The value of the expression
 7   7 
12
 k 1
k 1  k
3
is

k 1
4 k 1   4k  2
*43. Suppose that all the terms of an arithmetic progression (A.P.) are natural numbers. If the ratio of the sum of
the first seven terms to the sum of the first eleven terms is 6 : 11 and the seventh term lies in between 130
and 140, then the common difference of this A.P. is
*44. The coefficient of x9 in the expansion of (1 + x) (1 + x2) (1 + x3) ….. (1 + x100) is
x2 y 2
*45. Suppose that the foci of the ellipse   1 are (f1, 0) and (f2, 0) where f1 > 0 and f2 < 0. Let P1 and P2
9 5
be two parabolas with a common vertex at (0, 0) and with foci at (f1, 0) and (2f2, 0), respectively. Let T1 be
a tangent to P1 which passes through (2f2, 0) and T2 be a tangent to P2 which passes through (f1, 0). The m1
 1 
is the slope of T1 and m2 is the slope of T2, then the value of  2  m22  is
m 
46. Let m and n be two positive integers greater than 1. If
 e cos n   e  e
lim      
m
 0    2
m
then the value of is
n
47. If
1 2
9 x  3tan x   12  9 x 
 e
1
  2  dx
0
 1 x 
 3 
where tan1x takes only principal values, then the value of  log e 1     is
 4 

1
48. Let f :    be a continuous odd function, which vanishes exactly at one point and f (1) = . Suppose
2
x x
F  x 1
that F(x) =
1
 f  t  dt for all x  [1, 2] and G(x) =  t f  f  t   dt
1
for all x  [1, 2]. If lim
x 1 G  x 

14
,
1
then the value of f   is
2

option(s) is(are) correct.
 Marking scheme:
1
192 x 3 1
49. Let f   x   4
for all x   with f    0 . If m  f  x  dx  M , then the possible values of

2  sin x 2
1/ 2
m and M are
1 1
(A) m = 13, M = 24 (B) m  ,M 
4 2
(C) m = 11, M = 0 (D) m = 1, M = 12
*50. Let S be the set of all non-zero real numbers  such that the quadratic equation x2  x +  = 0 has two
distinct real roots x1 and x2 satisfying the inequality x1  x2  1 . Which of the following intervals is(are) a
subset(s) of S ?
 1 1   1 
(A)   ,   (B)   , 0
 2 5  5 
 1   1 1
(C)  0 ,  (D)  , 
 5   5 2
6 4
*51. If   3sin 1   and   3cos 1   , where the inverse trigonometric functions take only the principal
 11  9
values, then the correct option(s) is(are)
(A) cos > 0 (B) sin < 0
(C) cos( + ) > 0 (D) cos < 0
*52. Let E1 and E2 be two ellipses whose centers are at the origin. The major axes of E1 and E2 lie along the
x-axis and the y-axis, respectively. Let S be the circle x2 + (y  1)2 = 2. The straight line x + y = 3 touches
2 2
the curves S, E1 ad E2 at P, Q and R, respectively. Suppose that PQ = PR = . If e1 and e2 are the
3
eccentricities of E1 and E2, respectively, then the correct expression(s) is(are)
43 7
(A) e12  e22  (B) e1e2 
40 2 10
5 3
(C) e12  e22  (D) e1e2 
8 4

*53. Consider the hyperbola H : x2  y2 = 1 and a circle S with center N(x2, 0). Suppose that H and S touch each
other at a point P(x1, y1) with x1 > 1 and y1 > 0. The common tangent to H and S at P intersects the x-axis at
point M. If (l, m) is the centroid of the triangle PMN, then the correct expression(s) is(are)
dl 1 dm x1
(A)  1  2 for x1 > 1 (B)  for x1 > 1
dx1 3 x1 dx1 3 x 2  1  1 
dl 1 dm 1
(C)  1  2 for x1 > 1 (D)  for y1 > 0
dx1 3 x1 dy1 3
54. The option(s) with the values of a and L that satisfy the following equation is(are)
4
 e  sin at  cos4 at  dt
t 6
0

L?
 e  sin at  cos at  dt
t 6 4
e4  1 e4  1
(A) a = 2, L = (B) a = 2, L =
e  1 e  1
e4  1 e4  1
(C) a = 4, L = (D) a = 4, L =
e  1 e  1
55. Let f, g : [1, 2]   be continuous functions which are twice differentiable on the interval (1, 2). Let the
values of f and g at the points 1, 0 and 2 be as given in the following table:
x = 1 x=0 x=2
f (x) 3 6 0
g (x) 0 1 1
In each of the intervals (1, 0) and (0, 2) the function (f  3g) never vanishes. Then the correct
(A) f (x)  3g(x) = 0 has exactly three solutions in (1, 0)  (0, 2)
(B) f (x)  3g(x) = 0 has exactly one solution in (1, 0)
(C) f (x)  3g(x) = 0 has exactly one solution in (0, 2)
(D) f (x)  3g(x) = 0 has exactly two solutions in (1, 0) and exactly two solutions in (0, 2)
  
56. Let f (x) = 7tan8x + 7tan6x  3tan4x  3tan2x for all x    ,  . Then the correct expression(s) is(are)
 2 2
/ 4 / 4
1
(A)  xf  x  dx  (B)  f  x  dx  0
12
0 0
/ 4 / 4
1
(C)  xf  x  dx  6
0
(D) 
0
f  x  dx  1

 This section contains TWO paragraphs.

 Marking scheme:
PARAGRAPH 1
Let F :   be a thrice differentiable function. Suppose that F(1) = 0, F(3) = 4 and F (x) < 0 for all x 
(1/2, 3). Let f (x) = xF(x) for all x  .
57. The correct statement(s) is(are)

(A) f (1) < 0 (B) f (2) < 0
(C) f (x)  0 for any x  (1, 3) (D) f (x) = 0 for some x  (1, 3)
3 3
2 3
58. If  x F   x  dx  12 and  x F   x  dx  40 , then the correct expression(s) is(are)
1 1
3
(A) 9f (3) + f (1)  32 = 0 (B)  f  x  dx  12
1
3
(C) 9f (3)  f (1) + 32 = 0 (D)  f  x  dx  12
1
PARAGRAPH 2
Let n1 and n2 be the number of red and black balls, respectively, in box I. Let n3 and n4 be the number of red and
black balls, respectively, in box II.
59. One of the two boxes, box I and box II, was selected at random and a ball was drawn randomly out of this
1
box. The ball was found to be red. If the probability that this red ball was drawn from box II is , then the
3
correct option(s) with the possible values of n1, n2, n3 and n4 is(are)
(A) n1 = 3, n2 = 3, n3 = 5, n4 = 15 (B) n1 = 3, n2 = 6, n3 = 10, n4 = 50
(C) n1 = 8, n2 = 6, n3 = 5, n4 = 20 (D) n1 = 6, n2 = 12, n3 = 5, n4 = 20
60. A ball is drawn at random from box I and transferred to box II. If the probability of drawing a red ball from
1
box I, after this transfer, is , then the correct option(s) with the possible values of n 1 and n2 is(are)
3
(A) n1 = 4, n2 = 6 (B) n1 = 2, n2 = 3
(C) n1 = 10, n2 = 20 (D) n1 = 3, n2 = 6

PAPER-2 [Code – 4]
JEE (ADVANCED) 2015
ANSWERS
PART-I: PHYSICS
1. 2 2. 7 3. 4 4. 6
5. 3 6. 2 7. 2 8. 1
9. A 10. A, D 11. A, C 12. D
13. A, B 14. B, C 15. D 16. B or A, B, C
17. A, C 18. D 19. A, D 20. A, C
PART-II: CHEMISTRY
21. 8 22. 4 23. 4 24. 3

25. 5 26. 6 27. 3 28. 9
29. C 30. A 31. B 32. A
33. B, C 34. C, D 35. B 36. B,C,D
37. A 38. B 39. C 40. D
41. 9 42. 4 43. 9 44. 8

45. 4 46. 2 47. 9 48. 7
49. D 50. A, D 51. B, C, D 52. A, B
53. A, B, D 54. A, C 55. B, C 56. A, B
57. A, B, C 58. C, D 59. A, B 60. C, D

SOLUTIONS
PART-I: PHYSICS
nh 3h
1. mvr  
2  2
h 2r 2  a 0 (3) 2
de-Broglie Wavelength      2a 0
mv 3 3 z Li
2. For m closer to M
GMm Gm 2
 2  ma ...(i)
9 2 
and for the other m :
Gm 2 GMm
  ma ...(ii)
2 16 2
From both the equations,
k=7
3. E(t)  A 2 e t
 dE  A 2 e t dt  2AdAe t
Putting the values for maximum error,
dE 4
   % error = 4
E 100
2
4. I   4r 2 r 2 dr
3
IA   (r)(r 2 )(r 2 )dr
IB   (r 5 )(r 2 )(r 2 )dr
IB 6
 
IA 10
5. First and fourth wave interfere destructively. So from the interference of 2nd and 3rd wave only,
 2  
 Inet  I0  I0  2 I0 I0 cos     3I0
 3 3
n=3
1 1
6.  P  ; Q 
 2
R P (A 0  P )e P t
  t
RQ A 0 Q e Q
RP 2
At t  2 ; 
RQ e

3
7. Snell’s Law on 1st surface :  n sin r1
2
3
sin r1  ...(i)
2n
3 4n 2  3
 cos r1  1  =
4n 2 2n
r1  r2  60 ...(ii)
Snell’s Law on 2nd surface :
n sin r2  sin 
Using equation (i) and (ii)
n sin (60  r1 )  sin 
 3 1 
n cos r1  sin r1   sin 
 2 2 
d  3  d

dn  4
 
4n 2  3  1   cos 
 dn
for   60 and n  3
d
 2
dn
8. Equivalent circuit : 2
13
R eq   6 2
2 6.5V
So, current supplied by cell = 1 A
12 4
9. Q value of reaction = (140 + 94) × 8.5 – 236 × 7.5 = 219 Mev

So, total kinetic energy of Xe and Sr = 219 – 2 – 2 = 215 Mev
So, by conservation of momentum, energy, mass and charge, only option (A) is correct
10. From the given conditions, 1  1   2  2

From equilibrium, 1  2  1  2
2    2  2  2  1 
VP   1  g and VQ   g
9  2  9  1 

VP   
So,   1 and VP  VQ  0
VQ 2
11. BIc  VI  0I2c  VI  0Ic = V

 02 I2 c2  V 2
  0 I2   0 V 2   0 cV  I
  
12. E C1C2
30
C1  centre of sphere and C2  centre of cavity.

stress
13. Y
strain
1 strain 1 1
     YP  YQ
Y stress YP Y
 r2 
14. P(r) = K 1  2 
 R  
4 0
S C10 C20
15. C10  2  4 0S
d/2 d
2 0 S S
C 20  , C30  0
d d
1 1 1 d  1
   1 C30

C10 C10 C10 20S  2 
4 0 S
 
 C10
3d
7 0S
 
C 2  C30  C10
3d
C2 7

C1 3
kx
16. P (pressure of gas) = P1 
A
kx 2 (P  P )(V  V1 )
W   PdV  P1  V2  V1    P1 (V2  V1 )  2 1 2
2 2
3
U = nCVT =  P2 V2  P1V1 
2
Q = W + U
5P V 17P1V1 PV
Case I: U = 3P1V1, W  1 1 , Q  , U spring  1 1
4 4 4
9P1V1 7P1V1 41P1V1 PV
Case II: U = , W , Q , U spring  1 1
2 3 6 3
Note: A and C will be true after assuming pressure to the right of piston has constant value P1.
17. c n2
90  r  c
 sin(90  r)  c nm r n1
 cos r  sin c i
sin i n1 n
using  and sin c  2
sin r n m n1
n12  n 22
we get, sin 2 i m 
n 2m
Putting values, we get, correct options as A & C

18. For total internal reflection to take place in both structures, the numerical aperture should be the least one
for the combined structure & hence, correct option is D.
19. I1 = I2
 neA1v1 = neA2v2
 d1w1v1 = d2w2v2
Now, potential difference developed across MK
V = Bvw
V vw d
 1  1 1  2
V2 v2 w 2 d1
& hence correct choice is A & D
20. As I1 = I2
n1w1d1v1 = n2w2d2v2
V2 B2 v2 w 2  B2 w 2  n1w1d1  B2 n1
Now,    =
V1 B2 v1 w1  B1 w1  n 2 w 2 d 2  B1n 2
 Correct options are A & C
PART-II: CHEMISTRY
2
21.  Fe  C2 O 4  H2 O    MnO 42  8H  
 Mn 2   Fe3   4CO2  6H 2 O
So the ratio of rate of change of [H+] to that of rate of change of [MnO4] is 8.
22. 
H
H 
 

HO
P
aqueous dilute KMnO 4 (excess)
00 C
OH
HO OH
HO
Q 
23. CHO
CO, HCl
I 
Anhydrous AlCl /CuCl

3
CHCl 2 CHO
H 2O
II 
100ºC


COCl CHO
H2
III 
Pd  BaSO

4
CO2 Me CHO
DIBAL  H
IV 
Toluene,  78ºC

H2 O
24. PEt 3 O
Et 3 P CH3
C
Fe
OC Br
CO
The number of Fe – C bonds is 3.

25.  Co  en  2 Cl2  
 will show cis  trans isomerism
3
 CrCl 2  C2 O 4 2  

 Fe  H 2 O  4  OH  2  

 Fe  CN 4  NH3  2  
2
 Co  en 2  NH3  Cl  
2
 Co  NH 3  4  H 2 O  Cl    will not show cis  trans isomerism (Although it will show
geometrical isomerism)
26. B2 H 6  6MeOH   2B  OMe 3  6H 2
1 mole of B2H6 reacts with 6 mole of MeOH to give 2 moles of B(OMe)3.
3 mole of B2H6 will react with 18 mole of MeOH to give 6 moles of B(OMe)3
27.  H   X 
HX 
H    X  
Ka     
 HX 
 H   Y 
HY 
H    Y  
Ka     
 HY 
 m for HX   m1
 m for HY   m2
1
 m1  m
10 2
Ka = C2
2
 m 
Ka 1  C1   0 1 
 m 
 1 

2
 m 
Ka 2  C 2   0 2 
 m 
 2 
2 2
Ka1 C1  m  0.01  1 
  1      = 0.001
Ka 2 C 2  m  0.1  10 
 2 
pKa1  pKa 2  3
238 206
28. In conversion of 92 U to 82 Pb , 8 - particles and 6 particles are ejected.
The number of gaseous moles initially = 1 mol
The number of gaseous moles finally = 1 + 8 mol; (1 mol from air and 8 mol of 2He4)
So the ratio = 9/1 = 9
29. At large inter-ionic distances (because a → 0) the P.E. would remain constant.
However, when r → 0; repulsion would suddenly increase.
30. O O
H3C H3C C H H3C C H

 3
i O

 ii  Zn, H 2 O 
N H3
 
CH2 C H CH2 CH NH3
(R)
O O
OH O O
H3C H3C H3C C H
NH NH2
 
CH
OH CH2 OH CH2 CH NH2
OH
2H 2 O
H3C
N
(S)
31. CH3
C CH3
H3C CH CH3 
 O2
 
O
O
(U) H
CH
H3C CH3
(T)
32. N N Ph
NH2 N2 Cl OH
NaNO3 , HCl  Napthol / NaOH

00 C
  
V W

33. H O Cl (I)
H O Cl O (II)
H O Cl O (III)
O
O
H O Cl O (IV)
O
34. Cu 2  , Pb 2 , Hg 2 , Bi 3 give ppt with H2S in presence of dilute HCl.
35. CH3 CH3 CH3 CH3

H2O
Cl Si Cl   HO Si OH 
H O Si O Si O H
CH3 CH3 CH3 CH3 n
Me3SiCl, H 2 O
Me CH3 CH3 Me
Me Si O Si O Si O Si Me
Me CH3 CH3 n Me
36. * Adsorption of O2 on metal surface is exothermic.

* During electron transfer from metal to O2 electron occupies *2p orbital of O2.
* Due to electron transfer to O2 the bond order of O2 decreases hence bond length increases.
37. HCl  NaOH 

 NaCl  H 2 O
n = 100 1 = 100 m mole = 0.1 mole
Energy evolved due to neutralization of HCl and NaOH = 0.1  57 = 5.7 kJ = 5700 Joule
Energy used to increase temperature of solution = 200  4.2  5.7 = 4788 Joule
Energy used to increase temperature of calorimeter = 5700 – 4788 = 912 Joule
ms.t = 912
m.s5.7 = 912
ms = 160 Joule/C [Calorimeter constant]
Energy evolved by neutralization of CH3COOH and NaOH
= 200  4.2  5.6  160  5.6  5600 Joule
So energy used in dissociation of 0.1 mole CH3COOH = 5700  5600 = 100 Joule
Enthalpy of dissociation = 1 kJ/mole
1 100 1
38. CH 3COOH  
200 2
1  100 1
CH 3CONa  
200 2
pH  pK a  log
 salt 
acid 

1/ 2
pH  5  log 2  log
1/ 2
pH = 4.7
6
39.   double bond equivalent  8  1
C8 H 6  6
2
CH CH2
C CH
Pd/ BaSO 4
 H2

1 B2 H 6
HgSO 4 , H 2SO 4 , H 2 O  2  H 2O 2 , NaOH, H 2 O
O
CH2 CH2 OH
C CH3
(X)
(i) EtMgBr
(ii) H 2 O
OH CH3
Ph C H  / heat
CH3    Ph C CH CH3
(Y)
Et

   
41. s  4p  3q  5r
         
s  x  p  q  r   y  p  q  r   z  p  q  r 
   
s = (–x + y – z) p + (x – y – z) q + (x + y + z) r
 –x + y – z = 4
x–y–z=3
x+y+z=5
9 7
On solving we get x = 4, y = , z  
2 2
 2x + y + z = 9
12 k 
i i
e
k 1
7
e 7 1
12
42. 
 =4
3 i 3
e
k 1
i 4k  2 
e 1 7
43. Let seventh term be ‘a’ and common difference be ‘d’

S 6
Given 7   a = 15d
S11 11
Hence, 130 < 15d < 140
d=9
44. x9 can be formed in 8 ways

i.e. x9, x1 + 8, x2 + 7, x3 + 6, x4 + 5, x1 + 2 + 6, x1 + 3 + 5, x2 + 3 + 4 and coefficient in each case is 1
 Coefficient of x9 = 1 + 1 + 1 + .......... + 1 = 8
8 times
45. The equation of P1 is y2 – 8x = 0 and P2 is y2 + 16x = 0

Tangent to y2 – 8x = 0 passes through (–4, 0)
2 1
 0  m1  4    2 2
m1 m1
2
Also tangent to y + 16x = 0 passes through (2, 0)
4
 0  m2  2   m22  2
m2
1
  m 22  4
m12
e
  e
cos  n
e
46. lim 
 0 m 2
  cos  n 1 
ee

 1 cos  n  1

 e

lim  2n =  if and only if 2n – m = 0
 0 n
cos   1     
m 2n 2

1
9x 3tan x   12  9x 2  dx
1
47.  e 
0
 2 
 1 x 

Put 9x + 3 tan–1 x = t
 3 
 9  dx  dt
 1  x2 
3
9
4 3
9
=  e t dt = e 4 1
0
 3 
  log e 1     = 9
 4 
1
48. G (1) =  t f  f  t   dt  0
1
f ( x) =  f (x)
1
Given f (1) =
2
F  x   F 1
F x  x 1 f 1 1
lim  lim  
x 1 G  x   G 1
x 1 G x
  f  f 1  14
x 1
1/ 2 1
 
f 1/ 2  14
1
 f 7.
2
x x
192 192
49.  t 3 dt  f  x    t dt
3
3 2
1/ 2 1/2
4 4 3
16x  1  f  x   24x 
2
1 1 1
 3
 16x 4  1 dx   4
 f  x  dx    24x   dx
2
1/ 2 1/ 2 1/ 2
1
26 39
1
10

1/ 2
 f  x  dx  10  12
2
50. Here, 0 <  x1  x 2   1
2
 0 <  x1  x 2   4x1x 2  1
1
0< 4 1
2
 1 1   1 1
    ,   , 
 2 5   5 2

 3 3 5
51.    ,        
2 2 2 2
 sin  < 0; cos < 0
 cos( + ) > 0.
x2 y2  a2 b2 
52. For the given line, point of contact for E1 :   1 is  , 
a2 b2  3 3 
x2  B2 A 2 
y2
and for E2 :  1 is 
2
 , 2 
B A  3 3 
Point of contact of x + y = 3 and circle is (1, 2)
 r r  2 2
Also, general point on x + y = 3 can be taken as  1  ,2  where, r 
 2 2 3
1 8 5 4
So, required points are  ,  and  , 
 3 3 3 3
Comparing with points of contact of ellipse,
a2 = 5, B2 = 8
b2 = 4, A2 = 1
7 43
 e1e 2  and e12  e22 
2 10 40
 1 
53. Tangent at P, xx1 – yy1 = 1 intersects x axis at M  , 0 
 x1 
y y 0
Slope of normal =  1  1
x1 x1  x 2
 x2 = 2x1  N  (2x1, 0)
1
3x1 
x1 y
For centroid   , m 1
3 3
d 1
 1 2
dx1 3x1
dm 1 dm 1 dy1 x1
 ,  
dy1 3 dx1 3 dx1 3 x 2  1
1

54. Let
 e t  sin 6 at  cos 4 at  dt  A
0
2
I e t  sin 6 at  cos4 at  dt

Put t =  + x
dt = dx
for a = 2 as well as a = 4

I  e   e x  sin 6 ax  cos 4 ax  dx
0
I = eA
3
Similarly  e t  sin 6 at  cos 4 at  dt  e 2  A
2
A  e  A  e 2  A  e3  A e 4   1
So, L =  
A e 1
For both a = 2, 4

55. Let H (x) = f (x) – 3g (x)

H ( 1) = H (0) = H (2) = 3.
Applying Rolle’s Theorem in the interval [ 1, 0]
H(x) = f(x) – 3g(x) = 0 for atleast one c  ( 1, 0).
As H(x) never vanishes in the interval
 Exactly one c  ( 1, 0) for which H(x) = 0
Similarly, apply Rolle’s Theorem in the interval [0, 2].
 H(x) = 0 has exactly one solution in (0, 2)
56. f (x) = (7tan6x  3 tan2x) (tan2x + 1)

/ 4  /4
f  x  dx    7 tan x  3 tan 2 x  sec 2 xdx
6

0 0
/ 4
  f  x  dx  0
0
/ 4  /4
/ 4
 xf  x  dx   x  f  x  dx      f  x dx dx
 0
0 0
/ 4
1
 xf  x  dx  .
0
12
57. (A) f(x) = F(x) + xF(x)

f(1) = F(1) + F(1)
f(1) = F(1) < 0
f(1) < 0
(B) f(2) = 2F(2)
F(x) is decreasing and F(1) = 0
Hence F(2) < 0
 f(2) < 0
(C) f(x) = F(x) + x F(x)
F(x) < 0  x  (1, 3)
F(x) < 0  x  (1, 3)
Hence f(x) < 0  x  (1, 3)
3 3
58.  f  x  dx  
1 1
xF  x  dx
3
 x2  13
  F  x     x 2 F '  x  dx
2 1 2 1
9 1
= F  3  F 1  6 = –12
2 2
3 3
40   x 3 F  x    3 x 2 F  x  dx
1 1
40 = 27F(3) – F(1) + 36 … (i)

f(x) = F(x) + xF(x)
f(3) = F(3) + 3F(3)
f(1) = F(1) + F(1)
9f(3) –f(1) + 32 = 0.
59. P(Red Ball) = P(I)·P(R | I) + P(II)·P(R | II)

1 P(II)·P  R | II 
P  II | R   
3 P(I)·P  R | I   P(II)·P  R | II 

n3
1 n3  n4

3 n1 n3

n1  n 2 n 3  n 4
Of the given options, A and B satisfy above condition
60. P (Red after Transfer) = P(Red Transfer) . P(Red Transfer in II Case)

+ P (Black Transfer) . P(Red Transfer in II Case)
n1  n1  1  n 2  n1  1
P(R) =
n1  n 2  n1  n 2  1 n1  n 2 n1  n 2  1 3
Of the given options, option C and D satisfy above condition.

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JEE Advanced 2015 - Paper 2 MathonGo

READ THE INSTRUCTIONS CAREFULLY

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Section 1 (Maximum Marks: 32)

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7. A monochromatic beam of light is incident at 600 on one

Section 2 (Maximum Marks: 32)

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12. Consider a uniform spherical charge distribution R2

*13. In plotting stress versus strain curves for two materials P

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*16. An ideal monoatomic gas is confined in a horizontal

SECTION 3 (Maximum Marks: 16)

 This section contains TWO paragraphs

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 This section contains EIGHT questions

*22. The number of hydroxyl group(s) in Q is

H aqueous dilute KMnO (excess)

24. In the complex acetylbromidodicarbonylbis(triethylphosphine)iron(II), the number of Fe–C bond(s) is

25. Among the complex ions, [Co(NH2-CH2-CH2-NH2)2Cl2]+, [CrCl2(C2O4)2]3–, [Fe(H2O)4(OH)2]+,

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SECTION 2 (Maximum Marks: 32)

 This section contains EIGHT questions

30. In the following reactions, the product S is

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31. The major product U in the following reactions is

32. In the following reactions, the major product W is

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SECTION 3 (Maximum Marks: 16)

 This section contains TWO paragraphs

*38. The pH of the solution after Expt. 2 is

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(A) CH3 (B) CH3

40. The major compound Y is

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*44. The coefficient of x9 in the expansion of (1 + x) (1 + x2) (1 + x3) ….. (1 + x100) is

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Section 2 (Maximum Marks: 32)

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SECTION 3 (Maximum Marks: 16)

 This section contains TWO paragraphs.

57. The correct statement(s) is(are)

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21. 8 22. 4 23. 4 24. 3

41. 9 42. 4 43. 9 44. 8

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IA   (r)(r 2 )(r 2 )dr

IB   (r 5 )(r 2 )(r 2 )dr

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9. Q value of reaction = (140 + 94) × 8.5 – 236 × 7.5 = 219 Mev

10. From the given conditions, 1  1   2  2

11. BIc  VI  0I2c  VI  0Ic = V

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