RBT 2 - Paper 1
RBT 2 - Paper 1
▪ Please read the instructions carefully. You are allotted 5 minutes specifically for
this purpose.
▪ You are not allowed to leave the Examination Hall before the end of the test.
INSTRUCTIONS
Caution: Question Paper CODE as given above MUST be correctly marked in the answer
OMR sheet before attempting the paper. Wrong CODE or no CODE will give wrong results.
A. General Instructions
1. Attempt ALL the questions. Answers have to be marked on the OMR sheets.
2. This question paper contains Three Sections.
3. Section-I is Physics, Section-II is Chemistry and Section-III is Mathematics.
4. All the section can be filled in PART-A & B of OMR.
5. Rough spaces are provided for rough work inside the question paper. No additional sheets will be
provided for rough work.
6. Blank Papers, clip boards, log tables, slide rule, calculator, cellular phones, pagers and electronic
devices, in any form, are not allowed.
(ii) PART–A (05–12) contains Eight (8) Multiple Choice Questions which have One or More Than One
Correct answer.
Full Marks: +4 If only the bubble(s) corresponding to all the correct options(s) is (are) darkened.
Partial Marks: +1 For darkening a bubble corresponding to each correct option, provided NO incorrect
option is darkened.
Zero Marks: 0 If none of the bubbles is darkened.
Negative Marks: −2 In all other cases.
For example, if (A), (C) and (D) are all the correct options for a question, darkening all these three will result
in +4 marks; darkening only (A) and (D) will result in +2 marks; and darkening (A) and (B) will result in −2
marks, as a wrong option is also darkened.
(iii) Part-B (1 – 8) contains Eight (08) Numerical based questions, the answer of which maybe positive or
negative numbers or decimals TWO decimal places (e.g. 6.25, 7.00, -0.33, -.30, 30.27, -127.30) and each
question carries +3 marks for correct answer. There is no negative marking.
S
SEEC
CTTIIO
ONN –– II :: P
PHHY
YSSIIC
CSS
PART – A (Maximum Marks: 12)
This section contains FOUR (04) questions. Each question has FOUR options. ONLY ONE of these four
options is the correct answer.
1. A ball is projected from a point in one of the two smooth parallel vertical walls against the
other in a plane perpendicular to both. After being reflected at each wall impinge again on
the second at a point in the same horizontal plane as it started from. If “e” is the coefficient of
restitution, “a” is the distance between the walls and “R” is the free range on horizontal
surface, then which of the following is correct?
(A) Re3 = a(1 + e + e2) (B) Re = a(1 + e2 + e3)
(C) Re2 = a(1 + e + e2) (D) R = a(1 + e + e2)
2. A hemisphere rests in equilibrium on a rough ground and against an equally rough wall, if the
equilibrium is limiting, then the inclination of the base to the horizontal is
3 + 2
−1 8 +
2
(A) = sin−1 2
(B) = sin 2
8 1 + 3 1 +
8 + 2
−1 3 +
2
(C) = cos−1 2
(D) = cos 2
3 1 + 8 1 +
3. A cubical container of side ‘a’ and wall thickness x (x << a) is suspended in air and filled n
moles of diatomic gas (adiabatic exponent ) in a room where room temperature is T0. If at
time t = 0 gas temperature is T1 (T1 > T0), the temperature of gas ‘T’ at time ‘t’ is
6ka2 ( −1) 6ka2 ( −1)
− t − t
(A) T = T0 + T1e nRx (B) T = T0 − (T1 − T0 )e nRx
Q0
4. Two identical capacitor connected as shown and having v +–
initial charge Q0 each. Separation between plates of +–
+–
capacitor is d. Suddenly the left plate of upper capacitor and
right plate of lower capacitor start moving with speed v
+–
towards left while other plate of capacitor remains fixed. The +–
current in the circuit is +–
Q0 v
Q0 v Q0 v Q0 vt
(A) (B) (C) (D) zero
2d d 2d
Space For Rough Work
5. A strip of wood of mass M and length is placed on a smooth horizontal surface. An insect
of mass m starts at one end on the strip and walks to the other end in time t, moving with a
constant speed.
(A) the speed of the insect as seen from the ground is < .
t
M
t M + m
(B) the speed of the strip as seen from the ground is
m
(C) the speed of the strip as seen from the ground is
t M + m
2
1
(D) the total kinetic energy of the system is (m + M)
2 t
6. When photons of energy 4.25 eV strike the surface of a metal A, the ejected photoelectrons
have maximum kinetic energy TA eV and de-Broglie wavelength A. The maximum kinetic
energy of photoelectrons liberated from another metal B by photons of energy 4.70 eV is
TB = (TA – 1.50) eV. If the de-Broglie wavelength of these photoelectrons is B = 2A then
(A) the work function of A is 2.25 eV (B) the work function of B is 4.20 eV
(C) TA = 2.00 eV (D) TB = 2.75 eV
7. A tube of length l and radius R carries a steady flow of fluid whose density is and viscosity
is . The fluid flow velocity depends on the distance r from the axis of the tube
r2
as v = v0 1 − . Choose the correct option(s) from the following.
R 2
1 2
(A) the volume of the fluid flowing across the section of the tube per unit time is v0R 2
2
1
(B) the kinetic energy of the fluid within the tube's volume is R2v02
6
4
(C) the friction force exerted on the tube the fluid is v 0
4 v0
(D) the pressure difference at the ends of the tube is
R2
Space For Rough Work
10. An external magnetic field is decreased to zero due to which a current is induced in a
circular wire loop of radius r and resistance R placed in the field. This current will not
become zero.
(A) at the instant when external magnetic field stops changing (t = 0), the current in the loop
as a function of time for t 0 is given by i0e−2Rt/2F
(B) at the instant when B stops changing (t = 0), the current in the loop as a function of
0 IR
time t 0 is given by
2r
(C) the time in which current in loop decreases to 10−3 I0 (fromt = 0) for R = 100 and
32 ln10
and r = 5 cm is given by
1010
(D) the time in which current in loop decreases to 103 I0 (from t = 0 )for R = 100 and r = 5cm is
3 2
given by s
106
11. In the series L – C – R circuit, the voltage across resistance, capacitance and inductance are
30V each at frequency f = f0.
(A) It the inductor is short-circuited, the voltage across the capacitor will be 30 2 V.
30
(B) If the capacitor is short-circuited, the voltage drop across the inductor will be V.
2
(C) If the frequency is changed to 2f0, the ratio of reactance of the inductor to that of the
capacitor is 4 : 1.
(D) If the frequency is changed to 2f0, the ratio of the reactance of the inductor to that of the
capacitor is 1 : 4.
1. A machine is blowing spherical soap bubbles of different radii filled with helium gas. It is
found that if the bubbles have a radius smaller than 1 cm, then they sink to the floor in still
air. Larger bubbles float in the air. Assume that the thickness of the soap film in all bubbles is
uniform and equal. Assume that the density of soap solution is same as that of water
(=1000 kg m−3). The density of helium inside the bubbles and air are 0.18 kg m −3 and
1.23 kg m−3, respectively. If d is the thickness (in m) of the soap film of the bubbles which
are just floating, find the value of 2d.
2. Find the mass ratio MD/MH of deuterium and hydrogen (in near integer value) if their H lines
have wavelengths of 6561.01 Å and 6562 Å respectively.
P (N/m2)
3. Two moles of a monatomic ideal gas is taken
A B
through a cyclic process shown on pressure(P) - 2 10 5
4. A solid sphere of radius R = 0.2 m and of negligible mass is swimming in the water tank of
base surface area A = 0.5 m2. The depth of the water in the tank is h = 1 m. Determine the
work (in joules) needed to push to push the sphere down the bottom of tank. (Assume that
no water flows out of the tank. The density of water is = 1000 kg/m3 and g = 9.81 m/s2).
7. A battery is made by joining identical cells in m rows each row having m cells. The current
flowing in an external resistance R is i1. Now if the number of rows ‘m’ and number of cells in
m R
each row ‘n’ are interchanged, the current in external resistance is i2. If = 2 and = 4
2 r
i2
then the value of is
i1
0.25H 100
S
SEEC
CTTIIO
ONN –– IIII :: C
CHHE
EMMIIS
STTR
RYY
PART – A (Maximum Marks: 12)
This section contains FOUR (04) questions. Each question has FOUR options. ONLY ONE of these four
options is the correct answer.
1. The product A is
OH
( i) K 2CO3
⎯⎯⎯⎯⎯⎯ →A
( ii) CH3I
CH2OH
OH OCH 3
(A) (B)
CH2OCH 3 CH2OH
CH3 OCH 3
(C) (D)
CH2OH CHO
2. CH3
l3 P+Q+R
FeC
Cl 2/
Cl2 /h
v(1 e
q)
M
Which product can easily undergoes nucleophilic substitution reaction(SN1 and SN2 with
equal ease).
(A) P (B) Q
(C) R (D) M
Space For Rough Work
3. Which is most reactive towards aromatic nucleophilic substitution reaction towards NaOH?
Cl
Cl
CH3
CH3
(A) (B)
NO 2
NO 2
Cl
Cl
NO 2
(C) (D)
O 2N NO 2
NO 2
4.
OH P
O /Na
Br 2
P4O10
Q
CH3CH2CNH2 CH
3 CO
ON
a
LiA
lH R
4
S
Choose correct statement
(A) (P) and (S) are chain isomers (B) hydrolysis of (Q) produces carboxylic acid
(C) (R) is obtained by the fastest reaction (D) (S) contains four carbon atom
7. -
O
O
H3C
O
Br
Which of the statements regarding the product formed in the above reaction is/are correct?
(A) If Br is replaced with NO2 rate of reaction increases
(B) Inversion of configuration takes place.
(C) Nucleophillic acyl substitution takes place.
(D) Configuration at chiral carbon does not change
8. Which of the following compounds are more reactive than R - C - OH towards attack of
nucleophile?
(A) O (B) O
R - C - Cl R - C - CN
(C) O (D) O
R - C - NH 2 R-C-H
Reagent - X
11. Acetone can form an aromatic compound when treated with conc. H2SO4. Which of the
following reaction(s) do(es) not take place?
(A) oxidation (B) dehydration
(C) sulphonation (D) dehydrogenation
OH
CH3
OH
12. o
⎯⎯⎯⎯→
Cu/300 C
Product
CH 2OH
Which of the following(s) is/are minor product(s) or product(s) that are not formed at all?
HO CH3 HO CH3
O O
(A) (B)
CHO COOH
CH3 CH2
O O
(C) (D)
CHO CHO
1. 4 moles of a liquid A (V.P = 100 mm of Hg) was mixed with 6 moles of B(V.P = 400 mm of
x
Hg). If the mole fraction of A in the vapour above the solution is expressed as , what is the
y
value of (x + y)?
2. How many moles of O2 gas can be produced by passing eight Faraday of electricity into
sufficient water?
Space For Rough Work
5. 11.7 g of NaCl solid is added to 176.4 g of H2O. The degree of dissociation of NaCl in the
solution is 0.8. If the relative lowering of vapour pressure of water in the solution is
expressed as x 10-2, what is the value of x?
6. In a mixed metallic oxide, the oxide ion forms the hexagonal close packing(hcp) lattice. The
M2+ ions occupy ½ of the octahedral voids and the N3+ ions occupy 1/6th of the tetrahedral
x+ y+z
voids. If the formula of the solid is written as MxNyOz, what is the value of ?
10
8. 5.35 g of a salt of a strong acid and weak base is dissolved in water to make one litre
solution. The pH of the solution is found to be 5. The crystal of the salt contains NaCl type
unit cell. What is the mass of one mole of unit cell of the salt in gram unit?
[Kb of the weak base = 10–5]
Space For Rough Work
S
SEEC
CTTIIO
ONN –– IIiiii :: M
MAAT
THHE
EMMA
ATTIIC
CSS
PART – A (Maximum Marks: 12)
This section contains FOUR (04) questions. Each question has FOUR options. ONLY ONE of these four
options is the correct answer.
1. A varying parabola ‘S’ of latus rectum ‘4a’ touches y2 = 4ax, the axis of ‘S’ being parallel to x
– axis. The locus of vertex of ‘S’ is
(A) x + y + a = 0 (B) y2 = 16ax
(C) x + y − a = 0 (D) y2 = 8ax
2. On the open interval (–c, c), where c is a positive real number, y(x) is an infinitely
dy
differentiable solution of the differential equation = y 2 − 1 + cos x, with the initial condition
dx
y (0) = 0 . Then which one of the following is correct?
(A) y ( x ) has a local maximum at the origin
(B) y ( x ) has a local minimum at the origin.
(C) y ( x ) is strictly increasing on the open interval ( −, ) for some positive real number
(D) y ( x ) is strictly decreasing on the open interval ( −, ) for some positive real number .
1 1
3. Let f : ( 0, ) → ( 0, ) , f (1) = 2 be a twice differentiable function such that f ' = for
x f (x)
all x in given domain, then f ( 3 ) =
(A) 2 (B) 10
(C) 3 3 (D) 3
4. The values that ‘a’ can take so that the function f :R → R f ( x ) = x3 + x2 + acos x
is injective
1 1
(A) a , (B) a −, −
3 3
(C) a = 2 (D) No value of a
Space For Rough Work
x2 y2
5. Equation of ellipse E is + = 1 . Suppose C be a circle concentric with E intersecting the
16 4
ellipse in four points. Let A be a point on E and B be a point on C such that line joining A and
B is common tangent of ellipse E and circle C. If be maximum value of length AB and m
be its corresponding slope, then
(A) = 2 (B) m = 2
1
(C) = 6 (D) m =
2
7. If 2z + 3 = 3z + 4 , then
7
(A) z min = 2 (B) z max =
5
(C) z max = 2 (D) z min =1
10. The function f ( x ) is differentiable, continuous and f ( x ) 0 for all x on the interval 4, 8 .
( f ' ( x ))
2
8
1 1
Also f ( 4 ) = , f ( 8 ) = and f ( x) dx = 1. Find f ( 6 ) .
( )
4
4 2 4
1 1
(A) f ( 6 ) = (B) f ( 6 ) =
9 3
2
(C) f ( 5 ) = (D) f ( 5 ) = 3
7
z1 − z2
11. A relation R on the set of complex numbers is defined by z1 R z 2 if and only if is
z1 + z2
real. Then
(A) R is reflexive relation (B) R is symmetric relation
(C) R is transitive relation (D) R is equivalence relation
1. If number of arrangements of letters of the word MISSISSIPPI in which the first S precedes
the first I equals , then equals
10
2. For all real numbers x, f ( x ) is an increasing function that is differentiable and satisfies the
following conditions
2
5
(i) f (1) = 1, f ( x ) dx =
1
4
(ii) Let g ( x ) be inverse of f ( x ) , then for all x 1,g ( 2x ) = 2f ( x ) .
8
p
If x f ' ( x ) dx = q ; HCF (p,q) = 1, then p + q =
1
99
10 + n
3. The value of n99=1 is equal to (here [.] represents greatest integer function) is
10 − n
n =1
equal to
4. If the length of the shortest distance between any two opposite edges of the tetrahedron
formed by the planes whose equations are y + z = 0, z + x = 0, x + y = 0 and x + y + z = 3
is , then the value of 2 is equal to
6. Let positive vector of points A, B and C of triangle ABC respectively be ˆi + ˆj + 2k,ˆ ˆi + 2jˆ + kˆ
and 2iˆ + ˆj + kˆ . Let I1,I2 and I be the lengths of perpendiculars drawn from the orthocenter
3
1 f ( x)
7. Let f ( x ) = x sin x − (1 − cos x ) . The smallest positive integer k such that lim k 0 is
2 x →0 x
and satisfying h (i ) =
1
2
(h (i + 1) + h (i − 1) ) for every i = 1,2,.......,99 . Then the value of h(1) is
Space For Rough Work
Q
Q.. P
PCCooddee:: 110000995500
Answers
S
SEEC
CTTIIO
ONN –– II :: P
PHHY
YSSIIC
CSS
PART – A
1. C 2. B 3. D 4. B
5. AC 6. ABC 7. BCD 8. B
9. BCD 10. AC 11. BC 12. ABCD
PART – B
1. 7 2. 2 3. 7 4. 274.00
5. 4.58 6. 0.89 7. 1.50 8. 629.20
S
SEEC
CTTIIO
ONN –– IIII :: C
CHHE
EMMIIS
STTR
RYY
PART – A
1. B 2. D 3. D 4. B
5. AD 6. BC 7. ACD 8. ABD
9. ABC 10. BC 11. ACD 12. ABD
PART – B
1. 8 2. 2 3. 4 4. 1.4
5. 3.6 6. 1.1 7. 12.5 8. 214
S
SEEC
CTTIIO
ONN –– IIIIII :: M
MAATTH
HEEM
MAATTIIC
CSS
PART – A
1. D 2. D 3. B 4. C
5. AD 6. CD 7. BD 8. BD
9. BC 10. BC 11. ABCD 12. AD
PART – B
1. 924 2. 143 3. 2 4. 2.82
5. 1 6. 1.22 7. 4.00 8. 5.15
2. B
Sol. N1 = N2 …(1)
W = N1 + N2 …(2) N1
By (1) and (2)
W
N1 = …(2) N1
1 + 2 O
Balancing torque about ‘O’
3R
N1 × R + N2 × R = W sin
8 N2
8 + 2
Sin = N2
3 1 + 2 W
3. D
dQ K(6a2 ) (T − T0 ) R dT
Sol. = = n
dt x − 1 dt
6Ka2 ( − 1)
T t
dT
T − T0 = nRx o dt
T1
6Ka2 ( −1)t
T = T0 + (T1 − T0 )e nRx
4. B
q1 q2
Sol. = ; q1 + q2 = 2Q0
C1 C2
A A
C1 = 0 ; C2 = 0
d0 + vt d0 − vt
q1 d0 − vt
=
q2 d0 + vt
d − vt
q2 0 + q2 = 2Q0
d0 + vt
2d0
q2 = 2Q0
d0 + vt
2Q0
q2 = ( d0 + vt )
2d0
dq Qv
I= 2 = 0
dt d0
5. AC
6. ABC
Sol. KE = h –
7. BCD
Sol. Let dV be the volume flowing per second through the cylindrical shell of thickness dr then,
r2 r3
dV = (2rdr)v0 1 − 2 = 2v 0 r − 2 dr and the total volume,
R R
R
r3 R2 R2 v0
0
V = 2v0 r − 2 dr = 2v0
R 4
=
2
Let, dK be the kinetic energy, within the above cylindrical shell. Then
1 1
dK = (dm)v 2 = (2r )v 2dr
2 2
1 r2
= (2 )rv 20 1 − 2 dr
2 R
2r 3 r5
= lv20 r − 2 + 4 dr
R R
Hence, kinetic energy of the fluid,
R
2r3 r5 R2v02
0
K = lv20 r − 2 + 4
R R
dr =
6
Hence frictional force is the shearing force on the tube, exerted by the fluid, which
dv
equals −S , where S is the surface area of tube.
dr
r2 dv r
Given, v = v0 1 − 2
So = −2v 0 2
R dr R
dv 2v
and at r = R, =− 0
dr R
Then, viscous force is given by,
dv
dF = −(2Rl)
dr r =R
2v
= −2Rl − 0 = 4lv0
R
dv
Taking a cylindrical shell of thickness dr and radius r Viscous force, F = −(2rl) ,
dr
dv
Let, P be the pressure difference, the net force on the element = Pr2 + 2lr
dr
But, since the flow is steady, Fnet = 0
dv 2lr 2v r
−2lr 0 2 4lv
or P = dr = R
= 0
2 2 2
r r R
8. B
Sol. Let q be the instantaneous charge on the capacitor when a steady current I flows through
the circuit. Appling KVL on the circuit, we have
q qx 0 A
= + IR or = + IR C= .....(i)
C 0 A x
Differentiating eqn. (i) with respect to time, we get
q dx Ix
0= + +0 ( q = It)
0 A dt 0 A
Ix dx
or q = − where = velocity .....(ii)
(dx / dt) dt
From equationn (ii) substituting the value of q in equation (i). we have
x2
= −I + IR
0 A(dx /dt)
dx −I/ 0 A 2
or =v= x ....(iii)
dt − IR
dx I/ 0 A
or − =
2 dt ....(iv)
x − IR
Integrating the above expression w.r.t. time, we get
1 1 I/ 0 A
− = t ....(v)
x x0 − IR
From eqn (iii) and (v), we get
−2
I/ 0 A I/ 0 A 1
v= t +
IR − − IR x0
9. BCD
Sol. Apply Faraday law for direction of induced current.
10. AC
Sol. Flux linked with loop due to its own magnetic field,
0 I 2 rI
= (r ) = 0
2r 2
d r dI
emf induced = ==− 0
dt 2 dt
0 r dI
I= =−
R 2R dt
1 t
dI 2R
I0
I
=−
0 r
0
.dt;I = I0 e −2Rt/0 r
2Rt
−
0 r
−3
Now, 10 I0 = I0e = i0e−2Rt/0r
32 ln10
which gives t = s.
1010
11. BC
vL = vC = vR;
xL = xC = R
when inductor is short circuited
Z= R2 2
xC = 2R
30 30
I=
Z 2R
30 30
VL = ixL = ×R=
2R 2
(A) is incorrect and with similar calculations (B) will be correct.
Here f0 is the resonance frequency as vL = vC
1
0 = 2f0 =
LC
xL L
= = 2LC
xC 1 C
Given f = 2f0
= 20
xL
=4
xC
(C) is also correct.
12. ABCD
Sol. y = 2a cos (t + ) cos (Kx) comparison with given equation gives
2 1
K= = 10 = m
5
= 2f = 50 f = 25 Hz
v = 5 ms–1
at x = 0.15 m
cos (10 × 0.15) = cos (1.5)
= –1 for all t
at x = 0.3
cos (10 × 0.3) = cos 3 = – 0 for all t
PART – B
1. 7
Sol. For equilibrium of bubble.
4 4
4R2 d solg + R3 He g = R3air g
3 3
d → Thickness of soap solution.
d = 3.5 m.
2. 2
Sol. Use formula in terms of reduced mass
1 R z 2 1 1
= 2 − 2
m n1 n2
1 + M
m
1+
D MD
=
H m
1+
MH
MD
2.0
MH
3. 7
Sol. For process AB TA = 300 K , TB = 600 K
W = nRT = nR(TB − TA ) = 300 nR = 600R.
5
Q = n Cp T = 2 R (300) = 1500R.
2
vf p
For process BC W = nRT ln = nRT ln i = nRTln2 = 1200Rln2
vc pf
Q = W = 1200Rln2
300 K 2nRT
For process CA W = P dV = dT.
600 T K
= −2nR(300) = −1200R.
Q = nC V T + W
3
= 2 R( −300) − 1200R.
2
= −900R − 1200R = −2100R
600R + 1200Rln 2 − 1200R
=
1500R + 1200Rln 2
21
= 1− x = 7.
12ln 2 + 15
4. 274.00
4
R3
4 x 4 3
Sol. W = R g h − R + = R g h − R +
3 3
3 2 3 2A
5. 4.58
Sol. h = (R – r) [cos 30° – cos 60°]
1 1
mgh = mv 2 + mr 2 2
2 2
2 2 o
v sin 30
x=
2g
6. 0.89
Sol. 2g – T = 2a …(i)
TR = I …(ii)
a = R …(iii)
Ia
From (ii) and (iii) T = 2
R
I
2g = a 2 + 2
R
2g 2 9.8 9.8
a= = = 0.89 m/s2
I 0.2 11
2 + 2 2 + 0.01
R
7. 1.50
E E
Sol. i1 = & i2 =
r R r R
+ +
m n n m
r R m R
+ 1+
i2 m n n r = 3 = 1.5
= =
i1 r R m R 2
+ +
n m n r
8. 629.20
Sol. XL = 50 , XC = 100
Z1 = 100 – 50 I ; Z2 = 100 + 100 i (i = −1)
Z1Z2 100
Z= = (13 + i)
Z1 + Z2 17
100 13
Z= 170 ; cos =
17 170
2
V
P= . cos = 629.20
Z
S
SEEC
CTTIIO
ONN –– IIII :: C
CHHE
EMMIIS
STTR
RYY
PART – A
1. B
Sol. OH O OCH 3
K 2CO3
⎯⎯⎯⎯⎯ → + CH3I ⎯⎯
→
2. D
Sol. P, Q and R are formed by EAS reaction M is formed by free radical chlorination.
3. D
Sol. Electron withdrawing groups favour nucleophilic substitution when they are ortho and para to
leaving group.
4. B
Sol. P = CH3CH2NH2, Q = CH3CH2CN, R = Not formed, S = CH3CH2CH2NH2.
5. AD
Sol. AlCl3 + 3H2O ⎯⎯⎯⎯
Hydrolysis
→ Al ( OH)3 + 3HCl
B3+ cannot exist in aqueous media
6. BC
Sol. 2C+ 3H2 → C2 H6
( s) ( g) ( g)
H = 2 H
0
f
0
sub + 3 B.E (H − H) − B.E. ( C − C ) + 6 B.E ( C − H )
−85 = ( 2 718 ) + ( 3 436 ) − ( x + 6y )
x + 6y = 2829 …..1
Similarly for C3H8 ( g)
2x + 8y = 4002 …..2
Solving (1) & (2), x = 345
y = 414
7. ACD
Sol. - O
O
H3C O O O-
O CH3
Br
Br -
O
H3C +
O
O
Br
8. ABD
O
Sol. R - C - NH 2 has least +ve charge density among all of the given compound.
9. ABC
Sol. Bridge bonding
Al2Cl6 3c – 4e– Bond
10. BC
Sol. Original carbonyl compound can be generated from product by weak acid or base treatment.
11. ACD
CH3
H3C CH3
12. ABD
Sol. Dehydrogenation reaction takes place.
PART – B
1. 8
4 6
Sol. PT = p0A x A + pB0 xB = 100 + 400 = 280 mm of Hg
6+ 4 6+ 4
pA = yAPT
or, p0A x A = y APT or, 100 0.4 = yA 280
40 1
or, y A = =
280 7
x 1
=
y 7
so, (x + y) = 8
2. 2
Sol. 2O2− ⎯⎯→ O2 + 4e−
One mole of O2 produced by passing 4F electricity.
Two moles of O2 will be produced by passing 8F electricity.
3. 4
Sol. The oxidation number of N changes from -3 to +1 and +5 to +1.
4. 1.4
Sol. x = 2, y = 7, z = 5
CH2
X is CH 3 - C - CH 2 - CH 2 - CH 2 - CH 2 - CH 3
5. 3.6
po − p 0.2
Sol. = iXsolute = (1 + )
p o
10
= (1 + 0.8) (0.02) = 0.036
x 10–2 = 0.036 = 3.6 10–2
x = 3.6
6. 1.1
Sol. Formula of solid M3N2O6
x+y+z 3+2+6
= = 1.1
10 10
7. 12.5
Sol. of Al2(SO4)3 = of glucose
or, iC1RT = C2RT
or, iC1 = C2
or, 5 0.5 = 0.2
5 0.5
Ratio = = 12.5
0.2
8. 214
1 kw 1
Sol. pH = p − pkb − logC = 14 − 5 − logC = 5
2 2
or logC = -1 or C = 10-1 = 0.1 M
Mass of 0.1 mole of salt = 5.35 g
Mass of one mole of salt = 53.5 g
NaCl unit cell contains 4 units of NaCl
The unit cell of the salt contains 4 units of the salt
Mass of one mole of unit cell = 53.5 4 = 214
S
SEEC
CTTIIO
ONN –– IIIIII :: M
MAATTH
HEEM
MAATTIIC
CSS
PART – A
1. D
Sol. Let the vertex he (h, k).
So, ‘S’ can be assumed as ( y − k ) = −4a ( x − h )
2
y2 = 8ax
2. D
Sol. y ( 0) = y ' (0) = y " (0) = 0
y "' ( 0 ) = −1
y "' ( x ) is negative in the neighbourhood of x = 0
y " ( x ) is a decreasing function in the neighbourhood of x = 0.
For x 0 For x 0
y " ( x ) y " (0 ) y " ( x ) y " (0 )
y " ( x) 0 y " ( x) 0
Clearly, the concavity of curve changes from positive to negative across x = 0
So x = 0 is point of inflection
So the answer should therefore be (D).
Also, by n – th derivative test if f n ( c ) 0 (n is odd) then x = c is neither point of maxima nor
minima.
3. B
1
Sol. f ' f (x) = 1
x
1 1
Replace x by , we get f ' ( x ) f = 1
x x
1 1 1
Differentiating f " ( x ) f + f ' ( x ) f ' − 2 = 0
x x x
f " (x) f '(x) 1
− . =0
f ' ( x ) f ( x ) x2
f " (x) f (x) 1
f ( x ) dx = dx
( f ' ( x ))
2
x2
1 1 1
− f (x) − − f ' ( x ) dx = − + c
f ' (x) f ' (x)
x
f (x) 1
− +x=− +c
f '(x) x
f (1) 2
Put x = 1 − + 1 = −1 + c c = 2 − =2−2=0
f ' (1) 1
2
f (x) 1
=x+
f '(x) x
f '(x)
f (x)
=
x
x +1
2
n ( f ( x )) =
1
2
n 1 + x2 + c ' ( )
1
n 2= n2 + c ' c ' = 0
2
f ( x ) = 1 + x 2 f ( 3 ) = 10
4. C
Sol. f ' ( x ) = 3x2 + 2x − asin x; f " ( x ) = 6x + 2 − acos x
Clearly f ' ( 0) = 0
So, for f to be injective f ' ( x ) must attain minima at x = 0
f " (0) = 0 6 (0) + 2 − a = 0 a = 2
5. AD
Sol.
A ( acos , bsin )
O
D
6. CD
Sol. Since P is a probability distribution, we have P ( w ) = 1
n=1
n
1 1 1
P ( wn ) = ( w n−1 ) = 2 P ( w n−2 ) = ... = n−1 P ( w1 )
2 2 2
1 1
n=1
P ( w n ) = 1 n=1 2
n−1
P ( w 1 ) = 1 P ( w 1 n−1 = 1 P ( w1 )( 2 ) = 1
)
n=1 2
1
So, P ( w1 ) =
2
Clearly, the set A contains all natural numbers greater than 4 (excluding 6)
So, P (B ) = 1 − P ( w1 ) + P ( w 2 ) + P ( w 3 ) + P ( w 4 ) + P ( w 6 )
1 1 1 1 1 3
= 1− + + + + =
2 4 8 16 64 64
7. BD
Sol.
2 2 2
(
2z + 3 = 3z + 4 4 z + 9 + 6 z + z = 9 z + 16 + 12 z + z ) 2
( )
( )
5 z + 7 = −6 z + z = −12Re ( z ) 12 z
2
5 z − 12 z + 7 0 ( 5 z − 7 )( z − 1) 0 1 z
2 7
5
8. BD
Sol.
(B) If x f −1 ( Q) f −1 (R) x f −1 (Q) OR x f −1 (R) f ( x ) Q OR f ( x ) R
f ( x ) Q R x f −1 (Q R )
If x f −1 ( Q R) f ( x ) Q or f ( x ) R x f −1 (Q) or x f −1 (R ) x ( f −1 ( Q ) f −1 (R ) )
f −1 ( Q) f −1 (R) = f −1 (Q R)
9. BC
If ( gof ) exists then gof must be one – one and onto
−1
Sol.
gof is one – one f is one – one
gof is onto g is onto
Consequently, since ( gof ) exists, then gof is one – one and onto, hence f is one – one and
−1
g is onto
Hence g is ONTO
10. BC
f ' (x) 1
Sol. Let g ( x ) = g ( x ) dx = − +c
( f ( x ))
2
f (x)
8
1 1
g ( x ) dx = − + = −2 + 4 = 2
4
f (8) f ( 4)
8
(g ( x ))
2
Also, dx = 1
4
2
1
8
g(x) − = 0
4
2
1
g(x) =
2
f ' (x) 1
=
( f ( x )) 2
2
1 x
− = +d
f (x) 2
1
d = −6 using f ( 4 ) =
4
2
f (x) =
12 − x
1
f (6) =
3
11. ABCD
z1 − z2
Sol. z1 R z1 = 0 = a real number R is reflexive
z1 + z2
z1 − z2 z − z1 z − z2
If z1 R z 2 holds i.e. is real then clearly 2 = − 1 is also real
z1 + z2 z 2 + z1 z1 + z 2
R is symmetric
z1 − z2 z − z2 z1 − z2
If is real i.e. 1 =
z1 + z2 z1 + z2 z1 + z2
z1 z1 + z1 z2 − z1 z2 − z2 z2 = z1 z1 − z1 z2 + z1z2 − z2 z2
z1 z = z1 z2
z1 z2
=
z1 z2
z 2 − z3 z z
So, if is real, in same manner we have 2 = 3
z 2 + z3 z2 z3
z1 z 2 z3
= = R is transitive.
z1 z 2 z3
12. AD
Sol. Derangement of 4 persons in 4 houses = D4 = 9 ways. Hence option A.
If A has two houses. Then let there be a hypothetical person E. So that A, B, C, D, E have
one house each now.
Among the total derangements (D5 = 44 ) . A is equally likely to go to B, C, D, E houses. So
1
A does not go to E’s house in D5 ways.
4
1 1
Number of ways = D5 − D5 = 44 − ( 44 ) = 33 ways
4 4
But it is OK, for E to go to A’C house, it means one of A’s houses is occupied.
So, number of derangements in this case = D4 = 9
Required number of ways = 33 + 9 = 42 ways
PART – B
1. 924
Sol. Consider the first S, I, P
* S * I * P *
The second P can only be placed in the last gap and hence we have * S * I * P *
The three I’s can be placed only in the last three gaps.
Choosing the places for I’s is put 3 identical object into 3 boxes i.e.
3 +3 −1
C3−1 = 5C2 = 10 ways ( x1 + x2 + x3 = 3 )
We have so far placed 7 letters. We have to put 3S’s in the gaps created by these. However,
for placing the 3 – S’s, we cannot choose the gap before the first S and hence we have 7 –
gaps to choose from
This can be done in 7+3−1C2−1 = 9C6 = 84 ways .
Only, the letter M remains to be placed. M can go in any of these 11 – gaps.
Required number of ways = 10 84 11 = 9240
2. 143
Sol. f ( 2) = g ( 2),f ( 4) = g ( 4),f (8 ) = g (8 )
8 8 8
x f ' ( x ) = x f ( x ) 1 − f ( x ) dx = 8f (8 ) − f (1) = 63 − f ( x ) dx
8
1 1 1
2 2
g ( 2x ) 4
g(t)
f ( x ) dx =
1 1
2
dx =
2
4
dt ( t = 2x )
2 4 4
5 5 1
f ( x ) dx =
1
4
= g ( t ) dt g ( x ) dx = 5
4 42 2
4 4 4
f ( x ) dx + g ( x ) dx = 16 − 4 = 12 f ( x ) dx = 7
2 2 2
4
g ( 2x ) 4
g(t) 8
dx = 7 dt = 7 g ( x ) dx = 28
2
2 2
4 4
8 8
f ( x ) dx + g ( x ) dx = 64 − 16 = 48
4 4
8
f ( x ) dx = 48 − 28 = 20
4
8
2 4 8
x f ' ( x ) dx = 63 − f ( x ) dx + f ( x ) dx + f ( x ) dx
1 1 2 4
5 139 p
= 63 − + 7 + 20 = =
4 4 q
p + q = 143
3. 2
Sol. A = 10 + 1 + 10 + 2 + ...... + 10 + 99
B = 10 − 1 + 10 − 2 + ...... + 10 − 99
A A −B
= 1+
B B
( 10 + )
99
A −B = i − 10 − i
I=1
( 10 + )
2
i − 10 − i = 10 + i + 10 − i − 2 10 2 − i
= 20 − 2 100 − i
10 + i − 10 − i = 20 − 2 100 − i = 2 10 − 100 − i
( )
99 99 99
A −B = 10 + i − 10 − i = 2 10 − 100 − i = 2 10 − i =B 2
i=1 i=1 i=1
A −B
= 2
B
4. 2.82
Sol. The equation of two edges can be taken to be
x−0 y−0 z−0 x −0 y −0 z− 3
= = and = =
1 1 −1 1 −1 0
The shortest distance between them is 2 .
5. 1
Sol. x = f ( t ) dx = f ' ( t ) dt
0
I = (f (t) − t) f ' ( t ) dt
2023
1
1
= − ( t − f ( t ) ) f ' ( t ) dt
2023
0
1
= − ( t − f ( t )) ( −1 + f ' ( t ) + 1) dt
2023
0
1
= + ( t − f ( t )) (1 − f ' ( t ) ) dt − I
2023
( f − f ( t ))
2024 1
1
2I = ( t − f ( t ) ) (1 − f ' ( t ) )
2023 2
dt = =
0
2024 2024
0
6. 1.22
Sol. Clearly, triangle formed by the given points ˆi + ˆj + 2k,
ˆ ˆi + 2jˆ + kˆ and 2iˆ + ˆj + kˆ is equilateral
as AB = BC = AC = 2 .
Distance of orthcentre ‘O’ from the sides is equal to inradius of the triangle.
3
( 2)
2
1
l1 = l2 = l3 = inradius = r = = 4 =
s 4
2
( 2) 6
3 6
(l1 + l2 + l3 ) = =
6 2
7. 4.00
1
f ( x) x sin x − 1 + cos x
Sol. lim k = lim 2
x →0 x x →0 xk
1 1
sin x + x cos x − sin x
= lim 2 2
x →0 k xk −1
1 1 1
cos x + cos x − sin x − cos x
= lim 2 2 2
x →0 k (k − 1) xk −2
1
− sin x
= lim 2
x →0 k ( k − 1) x −3
1
f (x) −
2 −1
If k − 3 = 1 i.e. k = 4 , lim = =
x →0 xk 4 3 24
8. 5.15
Sol. Clearly h (i) is an A.P.
h (100) = h ( 0) + 100d 100d = 20 − 5 = 15 d = 0.15
h (1) = 5.15