Page 1
1
FINAL JEE –MAIN EXAMINATION – JULY, 2022
(Held On Monday 25
th
July, 2022) TIME : 9 : 00 AM to 12 : 00 NOON
PHYSICS TEST PAPER WITH SOLUTION
SECTION-A
1. If momentum [P], area [A] and time [T] are taken
as fundamental quantities, then the dimensional
formula for coefficient of viscosity is :
(A) [P A
-1
T
0
] (B) [P A T
-1
]
(C) [P A
-1
T] (D) [P A
-1
T
-1
]
Official Ans. by NTA (A)
Sol. Viscosity = pascal.second
P
x
A
y
T
z
= [M
1
L
-1
T
-1
]
[M
1
L
+1
T
-1
]
x
[L
2
]
y
[T
1
]
z
= M
1
L
-1
T
-1
M
x
L
+x+2y
T
-x+z
= M
1
L
-1
T
-1
x = 1 x + 2y = -1 -x + z = -1
y = -1
z = 0
Viscosity = P
1
A
-1
T
0
2. Which of the following physical quantities have
the same dimensions ?
(A) Electric displacement (D) and surface charge
density
(B) Displacement current and electric field
(C) Current density and surface charge density
(D) Electric potential and energy
Official Ans. by NTA (A)
Sol. Electric displacement
0
DE ??
? ? ? ?
00
0
DE
?? ?
? ? ? ?
??
?
??
[D] = [ ?]
? Surface change density = ?.
3. A person moved from A to B on a circular path as
shown in figure. If the distance travelled by him is
60 m, then the magnitude of displacement would
be : (Given cos135° = - 0.7)
(A) 42 m (B) 47 m
(C) 19 m (D) 40 m
Official Ans. by NTA (B)
Sol. d = R ?
3
60 R
4
? ??
?
??
??
60 4 80
Rm
3
?
??
??
Displacement
2 2 2
R R 2R cos135 ? ? ?
? ?
22
2R 2R 0.7 ? ? ?
2
2
80
3.4R 3.4
??
??
??
?
??
? 47 m
4. A body of mass 0.5 kg travels on straight line path
with velocity v = (3x
2
+ 4)m/s. The net workdone
by the force during its displacement from x = 0 to
x = 2 m is :
(A) 64 J (B) 60 J
(C) 120 J (D) 128 J
Official Ans. by NTA (B)
Sol. v
i
= 3(0
2
) + 4 = 4 ? x = 0
v
F
= 3(2)
2
+ 4 ? x = 2
= 16
? ?
22
1
W K m 16 4
2
? ? ? ?
11
(256 16)
22
? ? ?
240
60J
4
??
Page 2
1
FINAL JEE –MAIN EXAMINATION – JULY, 2022
(Held On Monday 25
th
July, 2022) TIME : 9 : 00 AM to 12 : 00 NOON
PHYSICS TEST PAPER WITH SOLUTION
SECTION-A
1. If momentum [P], area [A] and time [T] are taken
as fundamental quantities, then the dimensional
formula for coefficient of viscosity is :
(A) [P A
-1
T
0
] (B) [P A T
-1
]
(C) [P A
-1
T] (D) [P A
-1
T
-1
]
Official Ans. by NTA (A)
Sol. Viscosity = pascal.second
P
x
A
y
T
z
= [M
1
L
-1
T
-1
]
[M
1
L
+1
T
-1
]
x
[L
2
]
y
[T
1
]
z
= M
1
L
-1
T
-1
M
x
L
+x+2y
T
-x+z
= M
1
L
-1
T
-1
x = 1 x + 2y = -1 -x + z = -1
y = -1
z = 0
Viscosity = P
1
A
-1
T
0
2. Which of the following physical quantities have
the same dimensions ?
(A) Electric displacement (D) and surface charge
density
(B) Displacement current and electric field
(C) Current density and surface charge density
(D) Electric potential and energy
Official Ans. by NTA (A)
Sol. Electric displacement
0
DE ??
? ? ? ?
00
0
DE
?? ?
? ? ? ?
??
?
??
[D] = [ ?]
? Surface change density = ?.
3. A person moved from A to B on a circular path as
shown in figure. If the distance travelled by him is
60 m, then the magnitude of displacement would
be : (Given cos135° = - 0.7)
(A) 42 m (B) 47 m
(C) 19 m (D) 40 m
Official Ans. by NTA (B)
Sol. d = R ?
3
60 R
4
? ??
?
??
??
60 4 80
Rm
3
?
??
??
Displacement
2 2 2
R R 2R cos135 ? ? ?
? ?
22
2R 2R 0.7 ? ? ?
2
2
80
3.4R 3.4
??
??
??
?
??
? 47 m
4. A body of mass 0.5 kg travels on straight line path
with velocity v = (3x
2
+ 4)m/s. The net workdone
by the force during its displacement from x = 0 to
x = 2 m is :
(A) 64 J (B) 60 J
(C) 120 J (D) 128 J
Official Ans. by NTA (B)
Sol. v
i
= 3(0
2
) + 4 = 4 ? x = 0
v
F
= 3(2)
2
+ 4 ? x = 2
= 16
? ?
22
1
W K m 16 4
2
? ? ? ?
11
(256 16)
22
? ? ?
240
60J
4
??
2
5. A solid cylinder and a solid sphere, having same
mass M and radius R, roll down the same inclined
plane from top without slipping. They start from
rest. The ratio of velocity of the solid cylinder to
that of the solid sphere, with which they reach the
ground, will be :
(A)
5
3
(B)
4
5
(C)
3
5
(D)
14
15
Official Ans. by NTA (D)
Sol.
22
2gH
V
1 k / R
?
?
22
cylinder sphere
22
sphere cylinder
V (1 k / R )
V (1 k / R )
?
?
?
1 2 / 5 7 2
1 1/ 2 5 3
?
? ? ?
?
14
15
?
6. Three identical particle A, B and C of mass 100 kg
each are placed in a straight line with
AB = BC = 13 m. The gravitational force on a
fourth particle P of the same mass is F, when
placed at a distance 13 m from the particle B on the
perpendicular bisector of the line AC. The value of
F will be approximately :
(A) 21 G (B) 100 G
(C) 59 G (D) 42 G
Official Ans. by NTA (B)
Sol.
2 2
GMM GMM
F2
r ( 2r)
??
2
GMM 1
1
r 2
??
??
??
??
4
2
G 10 1
1
13 2
?? ?
??
??
??
F 100G
7. A certain amount of gas of volume V at 27°C
temperature and pressure 2 × 10
7
Nm
-2
expands
isothermally until its volume gets doubled. Later it
expands adiabatically until its volume gets
redoubled. The final pressure of the gas will be
(Use ? = 1.5)
(A) 3.536 × 10
5
Pa (B) 3.536 × 10
6
Pa
(C) 1.25 × 10
6
Pa (D) 1.25 × 10
5
Pa
Official Ans. by NTA (B)
Sol.
7
1
P 2 10 Pa ??
P
1
V
1
= P
2
V
2
Since V
2
= 2V
1
Hence P
2
= P
1
/2 (isothermal
expansion)
7
2
P 1 10 Pa ??
2 2 3 2
P (V ) P (2V )
??
?
7
6
3
1.5
1 10
P 3.536 10
2
?
? ? ?
8. Following statements are given :
(1) The average kinetic energy of a gas molecule
decreases when the temperature is reduced.
(2) The average kinetic energy of a gas molecule
increases with increase in pressure at constant
temperature.
(3) The average kinetic energy of a gas molecule
decreases with increases in volume.
(4) Pressure of a gas increases with increase in
temperature at constant pressure.
(5) The volume of gas decreases with increase in
temperature.
Choose the correct answer from the options given
below :
(A) (1) and (4) only (B) (1), (2) and (4) only
(C) (2) and (4) only (D) (1), (2) and (5) only
Official Ans. by NTA (A)
Sol.
avg
3
KE KT
2
?
2
rms
1
PV
3
??
Note : Statement (4) is correct only if we
consider it at constant volume and not constant
pressure. Ideally, this question must be bonus
but most appropriate answer is option (A)
Page 3
1
FINAL JEE –MAIN EXAMINATION – JULY, 2022
(Held On Monday 25
th
July, 2022) TIME : 9 : 00 AM to 12 : 00 NOON
PHYSICS TEST PAPER WITH SOLUTION
SECTION-A
1. If momentum [P], area [A] and time [T] are taken
as fundamental quantities, then the dimensional
formula for coefficient of viscosity is :
(A) [P A
-1
T
0
] (B) [P A T
-1
]
(C) [P A
-1
T] (D) [P A
-1
T
-1
]
Official Ans. by NTA (A)
Sol. Viscosity = pascal.second
P
x
A
y
T
z
= [M
1
L
-1
T
-1
]
[M
1
L
+1
T
-1
]
x
[L
2
]
y
[T
1
]
z
= M
1
L
-1
T
-1
M
x
L
+x+2y
T
-x+z
= M
1
L
-1
T
-1
x = 1 x + 2y = -1 -x + z = -1
y = -1
z = 0
Viscosity = P
1
A
-1
T
0
2. Which of the following physical quantities have
the same dimensions ?
(A) Electric displacement (D) and surface charge
density
(B) Displacement current and electric field
(C) Current density and surface charge density
(D) Electric potential and energy
Official Ans. by NTA (A)
Sol. Electric displacement
0
DE ??
? ? ? ?
00
0
DE
?? ?
? ? ? ?
??
?
??
[D] = [ ?]
? Surface change density = ?.
3. A person moved from A to B on a circular path as
shown in figure. If the distance travelled by him is
60 m, then the magnitude of displacement would
be : (Given cos135° = - 0.7)
(A) 42 m (B) 47 m
(C) 19 m (D) 40 m
Official Ans. by NTA (B)
Sol. d = R ?
3
60 R
4
? ??
?
??
??
60 4 80
Rm
3
?
??
??
Displacement
2 2 2
R R 2R cos135 ? ? ?
? ?
22
2R 2R 0.7 ? ? ?
2
2
80
3.4R 3.4
??
??
??
?
??
? 47 m
4. A body of mass 0.5 kg travels on straight line path
with velocity v = (3x
2
+ 4)m/s. The net workdone
by the force during its displacement from x = 0 to
x = 2 m is :
(A) 64 J (B) 60 J
(C) 120 J (D) 128 J
Official Ans. by NTA (B)
Sol. v
i
= 3(0
2
) + 4 = 4 ? x = 0
v
F
= 3(2)
2
+ 4 ? x = 2
= 16
? ?
22
1
W K m 16 4
2
? ? ? ?
11
(256 16)
22
? ? ?
240
60J
4
??
2
5. A solid cylinder and a solid sphere, having same
mass M and radius R, roll down the same inclined
plane from top without slipping. They start from
rest. The ratio of velocity of the solid cylinder to
that of the solid sphere, with which they reach the
ground, will be :
(A)
5
3
(B)
4
5
(C)
3
5
(D)
14
15
Official Ans. by NTA (D)
Sol.
22
2gH
V
1 k / R
?
?
22
cylinder sphere
22
sphere cylinder
V (1 k / R )
V (1 k / R )
?
?
?
1 2 / 5 7 2
1 1/ 2 5 3
?
? ? ?
?
14
15
?
6. Three identical particle A, B and C of mass 100 kg
each are placed in a straight line with
AB = BC = 13 m. The gravitational force on a
fourth particle P of the same mass is F, when
placed at a distance 13 m from the particle B on the
perpendicular bisector of the line AC. The value of
F will be approximately :
(A) 21 G (B) 100 G
(C) 59 G (D) 42 G
Official Ans. by NTA (B)
Sol.
2 2
GMM GMM
F2
r ( 2r)
??
2
GMM 1
1
r 2
??
??
??
??
4
2
G 10 1
1
13 2
?? ?
??
??
??
F 100G
7. A certain amount of gas of volume V at 27°C
temperature and pressure 2 × 10
7
Nm
-2
expands
isothermally until its volume gets doubled. Later it
expands adiabatically until its volume gets
redoubled. The final pressure of the gas will be
(Use ? = 1.5)
(A) 3.536 × 10
5
Pa (B) 3.536 × 10
6
Pa
(C) 1.25 × 10
6
Pa (D) 1.25 × 10
5
Pa
Official Ans. by NTA (B)
Sol.
7
1
P 2 10 Pa ??
P
1
V
1
= P
2
V
2
Since V
2
= 2V
1
Hence P
2
= P
1
/2 (isothermal
expansion)
7
2
P 1 10 Pa ??
2 2 3 2
P (V ) P (2V )
??
?
7
6
3
1.5
1 10
P 3.536 10
2
?
? ? ?
8. Following statements are given :
(1) The average kinetic energy of a gas molecule
decreases when the temperature is reduced.
(2) The average kinetic energy of a gas molecule
increases with increase in pressure at constant
temperature.
(3) The average kinetic energy of a gas molecule
decreases with increases in volume.
(4) Pressure of a gas increases with increase in
temperature at constant pressure.
(5) The volume of gas decreases with increase in
temperature.
Choose the correct answer from the options given
below :
(A) (1) and (4) only (B) (1), (2) and (4) only
(C) (2) and (4) only (D) (1), (2) and (5) only
Official Ans. by NTA (A)
Sol.
avg
3
KE KT
2
?
2
rms
1
PV
3
??
Note : Statement (4) is correct only if we
consider it at constant volume and not constant
pressure. Ideally, this question must be bonus
but most appropriate answer is option (A)
3
9. In figure (A), mass ‘2 m’ is fixed on mass ‘m’
which is attached to two springs of spring constant
k. In figure (B), mass ‘m’ is attached to two spring
of spring constant ‘k’ and ‘2k’. If mass ‘m’ in (A)
and (B) are displaced by distance ‘x’ horizontally
and then released, then time period T
1
and T
2
corresponding to (A) and (B) respectively follow
the relation.
(A)
1
2
T 3
T
2
? (B)
1
2
T 3
T2
?
(C)
1
2
T 2
T3
? (D)
1
2
T 2
T3
?
Official Ans. by NTA (A)
Sol.
1
3m
T2
2k
??
2
m
T2
3k
??
1
2
3m
2
T 3
2k
T
m2
2
3k
?
??
?
10. A condenser of 2 ?F capacitance is charged
steadily from 0 to 5C. Which of the following
graph represents correctly the variation of potential
difference (V) across it’s plates with respect to the
charge (Q) on the condenser ?
(A) (B)
(C) (D)
Official Ans. by NTA (A)
Sol. Q = CV
1
VQ
C
?
Straight line with slope =
1
C
Slope
5
6
11
5 10
C 2 10
?
? ? ? ?
?
11. Two charged particles, having same kinetic energy,
are allowed to pass through a uniform magnetic
field perpendicular to the direction of motion. If
the ratio of radii of their circular paths is 6 : 5 and
their respective masses ratio is 9 : 4. Then, the ratio
of their charges will be :
(A) 8 : 5 (B) 5 : 4
(C) 5 : 3 (D) 8 : 7
Official Ans. by NTA (B)
Sol. Radius of circular path
2mk
R
qB
?
2mk
q
RB
?
1 1 2
2 2 1
q m R 9 5 5
q m R 4 6 4
? ? ? ? ?
12. To increase the resonant frequency in series LCR
circuit,
(A) Source frequency should be increased
(B) Another resistance should be added in series
with the first resistance.
(C) Another capacitor should be added in series
with the first capacitor
(D) The source frequency should be decreased
Official Ans. by NTA (C)
Sol.
1
f
2 LC
?
?
To increase the resonating frequency product of L
and C should decrease.
By joining capacitor in series, capacitor will
decrease
Page 4
1
FINAL JEE –MAIN EXAMINATION – JULY, 2022
(Held On Monday 25
th
July, 2022) TIME : 9 : 00 AM to 12 : 00 NOON
PHYSICS TEST PAPER WITH SOLUTION
SECTION-A
1. If momentum [P], area [A] and time [T] are taken
as fundamental quantities, then the dimensional
formula for coefficient of viscosity is :
(A) [P A
-1
T
0
] (B) [P A T
-1
]
(C) [P A
-1
T] (D) [P A
-1
T
-1
]
Official Ans. by NTA (A)
Sol. Viscosity = pascal.second
P
x
A
y
T
z
= [M
1
L
-1
T
-1
]
[M
1
L
+1
T
-1
]
x
[L
2
]
y
[T
1
]
z
= M
1
L
-1
T
-1
M
x
L
+x+2y
T
-x+z
= M
1
L
-1
T
-1
x = 1 x + 2y = -1 -x + z = -1
y = -1
z = 0
Viscosity = P
1
A
-1
T
0
2. Which of the following physical quantities have
the same dimensions ?
(A) Electric displacement (D) and surface charge
density
(B) Displacement current and electric field
(C) Current density and surface charge density
(D) Electric potential and energy
Official Ans. by NTA (A)
Sol. Electric displacement
0
DE ??
? ? ? ?
00
0
DE
?? ?
? ? ? ?
??
?
??
[D] = [ ?]
? Surface change density = ?.
3. A person moved from A to B on a circular path as
shown in figure. If the distance travelled by him is
60 m, then the magnitude of displacement would
be : (Given cos135° = - 0.7)
(A) 42 m (B) 47 m
(C) 19 m (D) 40 m
Official Ans. by NTA (B)
Sol. d = R ?
3
60 R
4
? ??
?
??
??
60 4 80
Rm
3
?
??
??
Displacement
2 2 2
R R 2R cos135 ? ? ?
? ?
22
2R 2R 0.7 ? ? ?
2
2
80
3.4R 3.4
??
??
??
?
??
? 47 m
4. A body of mass 0.5 kg travels on straight line path
with velocity v = (3x
2
+ 4)m/s. The net workdone
by the force during its displacement from x = 0 to
x = 2 m is :
(A) 64 J (B) 60 J
(C) 120 J (D) 128 J
Official Ans. by NTA (B)
Sol. v
i
= 3(0
2
) + 4 = 4 ? x = 0
v
F
= 3(2)
2
+ 4 ? x = 2
= 16
? ?
22
1
W K m 16 4
2
? ? ? ?
11
(256 16)
22
? ? ?
240
60J
4
??
2
5. A solid cylinder and a solid sphere, having same
mass M and radius R, roll down the same inclined
plane from top without slipping. They start from
rest. The ratio of velocity of the solid cylinder to
that of the solid sphere, with which they reach the
ground, will be :
(A)
5
3
(B)
4
5
(C)
3
5
(D)
14
15
Official Ans. by NTA (D)
Sol.
22
2gH
V
1 k / R
?
?
22
cylinder sphere
22
sphere cylinder
V (1 k / R )
V (1 k / R )
?
?
?
1 2 / 5 7 2
1 1/ 2 5 3
?
? ? ?
?
14
15
?
6. Three identical particle A, B and C of mass 100 kg
each are placed in a straight line with
AB = BC = 13 m. The gravitational force on a
fourth particle P of the same mass is F, when
placed at a distance 13 m from the particle B on the
perpendicular bisector of the line AC. The value of
F will be approximately :
(A) 21 G (B) 100 G
(C) 59 G (D) 42 G
Official Ans. by NTA (B)
Sol.
2 2
GMM GMM
F2
r ( 2r)
??
2
GMM 1
1
r 2
??
??
??
??
4
2
G 10 1
1
13 2
?? ?
??
??
??
F 100G
7. A certain amount of gas of volume V at 27°C
temperature and pressure 2 × 10
7
Nm
-2
expands
isothermally until its volume gets doubled. Later it
expands adiabatically until its volume gets
redoubled. The final pressure of the gas will be
(Use ? = 1.5)
(A) 3.536 × 10
5
Pa (B) 3.536 × 10
6
Pa
(C) 1.25 × 10
6
Pa (D) 1.25 × 10
5
Pa
Official Ans. by NTA (B)
Sol.
7
1
P 2 10 Pa ??
P
1
V
1
= P
2
V
2
Since V
2
= 2V
1
Hence P
2
= P
1
/2 (isothermal
expansion)
7
2
P 1 10 Pa ??
2 2 3 2
P (V ) P (2V )
??
?
7
6
3
1.5
1 10
P 3.536 10
2
?
? ? ?
8. Following statements are given :
(1) The average kinetic energy of a gas molecule
decreases when the temperature is reduced.
(2) The average kinetic energy of a gas molecule
increases with increase in pressure at constant
temperature.
(3) The average kinetic energy of a gas molecule
decreases with increases in volume.
(4) Pressure of a gas increases with increase in
temperature at constant pressure.
(5) The volume of gas decreases with increase in
temperature.
Choose the correct answer from the options given
below :
(A) (1) and (4) only (B) (1), (2) and (4) only
(C) (2) and (4) only (D) (1), (2) and (5) only
Official Ans. by NTA (A)
Sol.
avg
3
KE KT
2
?
2
rms
1
PV
3
??
Note : Statement (4) is correct only if we
consider it at constant volume and not constant
pressure. Ideally, this question must be bonus
but most appropriate answer is option (A)
3
9. In figure (A), mass ‘2 m’ is fixed on mass ‘m’
which is attached to two springs of spring constant
k. In figure (B), mass ‘m’ is attached to two spring
of spring constant ‘k’ and ‘2k’. If mass ‘m’ in (A)
and (B) are displaced by distance ‘x’ horizontally
and then released, then time period T
1
and T
2
corresponding to (A) and (B) respectively follow
the relation.
(A)
1
2
T 3
T
2
? (B)
1
2
T 3
T2
?
(C)
1
2
T 2
T3
? (D)
1
2
T 2
T3
?
Official Ans. by NTA (A)
Sol.
1
3m
T2
2k
??
2
m
T2
3k
??
1
2
3m
2
T 3
2k
T
m2
2
3k
?
??
?
10. A condenser of 2 ?F capacitance is charged
steadily from 0 to 5C. Which of the following
graph represents correctly the variation of potential
difference (V) across it’s plates with respect to the
charge (Q) on the condenser ?
(A) (B)
(C) (D)
Official Ans. by NTA (A)
Sol. Q = CV
1
VQ
C
?
Straight line with slope =
1
C
Slope
5
6
11
5 10
C 2 10
?
? ? ? ?
?
11. Two charged particles, having same kinetic energy,
are allowed to pass through a uniform magnetic
field perpendicular to the direction of motion. If
the ratio of radii of their circular paths is 6 : 5 and
their respective masses ratio is 9 : 4. Then, the ratio
of their charges will be :
(A) 8 : 5 (B) 5 : 4
(C) 5 : 3 (D) 8 : 7
Official Ans. by NTA (B)
Sol. Radius of circular path
2mk
R
qB
?
2mk
q
RB
?
1 1 2
2 2 1
q m R 9 5 5
q m R 4 6 4
? ? ? ? ?
12. To increase the resonant frequency in series LCR
circuit,
(A) Source frequency should be increased
(B) Another resistance should be added in series
with the first resistance.
(C) Another capacitor should be added in series
with the first capacitor
(D) The source frequency should be decreased
Official Ans. by NTA (C)
Sol.
1
f
2 LC
?
?
To increase the resonating frequency product of L
and C should decrease.
By joining capacitor in series, capacitor will
decrease
4
13. A small square loop of wire of side l is placed
inside a large square loop of wire L (L >> l). Both
loops are coplanar and their centres coincide at
point O as shown in figure. The mutual inductance
of the system is :
(A)
2
0
2 2 L ?
?
(B)
2
0
2 2 L
?
?
(C)
2
0
22
L
?
?
(D)
2
0
L
22
?
?
Official Ans. by NTA (C)
Sol. Assuming current I in outer loop magnetic field at
centre
00
i 2 2 i
4 (2sin45 )
L
L
4
2
??
? ? ? ? ?
?
??
l
l
Flux through inner loop
M
i
?
2
0
22
M
L
?
?
?
14. The rms value of conduction current in a parallel
plate capacitor is 6.9 ?A. The capacity of this
capacitor, if it is connected to 230 V ac supply with
an angular frequency of 600 rad/s, will be :
(A) 5 pF (B) 50 pF
(C) 100 pF (D) 200 pF
Official Ans. by NTA (B)
Sol. Current in capacitor
C
V
I
X
?
? ? ? ? I V C ? ? ?
6
I 6.9 10
C 50pF
V 230 600
?
?
? ? ?
??
15. Which of the following statement is correct ?
(A) In primary rainbow, observer sees red colour
on the top and violet on the bottom
(B) In primary rainbow, observer sees violet colour
on the top and red on the bottom
(C) In primary rainbow, light wave suffers total
internal reflection twice before coming out of
water drops
(D) Primary rainbow is less bright than secondary
rainbow.
Official Ans. by NTA (A)
Sol. In primary rainbow, red colour is at top and violet
is at bottom.
Intensity of secondary rainbow is less in
comparison to primary rainbow.
16. Time taken by light to travel in two different
materials A and B of refractive indices ?
A
and ?
B
of same thickness is t
1
and t
2
respectively. If
t
2
– t
1
= 5 × 10
-10
s and the ratio of ?
A
to ?
B
is 1 : 2.
Then the thickness of material, in meter is : (Given
v
A
and v
B
are velocities of light in A and B
materials respectively).
(A) 5 × 10
-10
v
a
m (B) 5 × 10
-10
m
(C) (D) 5 × 10
-10
v
B
m
Official Ans. by NTA (A)
Sol.
A A B
B B A
c / V V 1
c / V V 2
?
? ? ?
?
Let the thickness is d
10
BA
dd
5 10
vv
?
? ? ?
10
AB
AB
5 10 v v
d
vv
?
??
?
?
As v
A
= 2v
B
? d = 5 × 10
-10
× 2v
B
Or d = 5 × 10
-10
× v
A
Page 5
1
FINAL JEE –MAIN EXAMINATION – JULY, 2022
(Held On Monday 25
th
July, 2022) TIME : 9 : 00 AM to 12 : 00 NOON
PHYSICS TEST PAPER WITH SOLUTION
SECTION-A
1. If momentum [P], area [A] and time [T] are taken
as fundamental quantities, then the dimensional
formula for coefficient of viscosity is :
(A) [P A
-1
T
0
] (B) [P A T
-1
]
(C) [P A
-1
T] (D) [P A
-1
T
-1
]
Official Ans. by NTA (A)
Sol. Viscosity = pascal.second
P
x
A
y
T
z
= [M
1
L
-1
T
-1
]
[M
1
L
+1
T
-1
]
x
[L
2
]
y
[T
1
]
z
= M
1
L
-1
T
-1
M
x
L
+x+2y
T
-x+z
= M
1
L
-1
T
-1
x = 1 x + 2y = -1 -x + z = -1
y = -1
z = 0
Viscosity = P
1
A
-1
T
0
2. Which of the following physical quantities have
the same dimensions ?
(A) Electric displacement (D) and surface charge
density
(B) Displacement current and electric field
(C) Current density and surface charge density
(D) Electric potential and energy
Official Ans. by NTA (A)
Sol. Electric displacement
0
DE ??
? ? ? ?
00
0
DE
?? ?
? ? ? ?
??
?
??
[D] = [ ?]
? Surface change density = ?.
3. A person moved from A to B on a circular path as
shown in figure. If the distance travelled by him is
60 m, then the magnitude of displacement would
be : (Given cos135° = - 0.7)
(A) 42 m (B) 47 m
(C) 19 m (D) 40 m
Official Ans. by NTA (B)
Sol. d = R ?
3
60 R
4
? ??
?
??
??
60 4 80
Rm
3
?
??
??
Displacement
2 2 2
R R 2R cos135 ? ? ?
? ?
22
2R 2R 0.7 ? ? ?
2
2
80
3.4R 3.4
??
??
??
?
??
? 47 m
4. A body of mass 0.5 kg travels on straight line path
with velocity v = (3x
2
+ 4)m/s. The net workdone
by the force during its displacement from x = 0 to
x = 2 m is :
(A) 64 J (B) 60 J
(C) 120 J (D) 128 J
Official Ans. by NTA (B)
Sol. v
i
= 3(0
2
) + 4 = 4 ? x = 0
v
F
= 3(2)
2
+ 4 ? x = 2
= 16
? ?
22
1
W K m 16 4
2
? ? ? ?
11
(256 16)
22
? ? ?
240
60J
4
??
2
5. A solid cylinder and a solid sphere, having same
mass M and radius R, roll down the same inclined
plane from top without slipping. They start from
rest. The ratio of velocity of the solid cylinder to
that of the solid sphere, with which they reach the
ground, will be :
(A)
5
3
(B)
4
5
(C)
3
5
(D)
14
15
Official Ans. by NTA (D)
Sol.
22
2gH
V
1 k / R
?
?
22
cylinder sphere
22
sphere cylinder
V (1 k / R )
V (1 k / R )
?
?
?
1 2 / 5 7 2
1 1/ 2 5 3
?
? ? ?
?
14
15
?
6. Three identical particle A, B and C of mass 100 kg
each are placed in a straight line with
AB = BC = 13 m. The gravitational force on a
fourth particle P of the same mass is F, when
placed at a distance 13 m from the particle B on the
perpendicular bisector of the line AC. The value of
F will be approximately :
(A) 21 G (B) 100 G
(C) 59 G (D) 42 G
Official Ans. by NTA (B)
Sol.
2 2
GMM GMM
F2
r ( 2r)
??
2
GMM 1
1
r 2
??
??
??
??
4
2
G 10 1
1
13 2
?? ?
??
??
??
F 100G
7. A certain amount of gas of volume V at 27°C
temperature and pressure 2 × 10
7
Nm
-2
expands
isothermally until its volume gets doubled. Later it
expands adiabatically until its volume gets
redoubled. The final pressure of the gas will be
(Use ? = 1.5)
(A) 3.536 × 10
5
Pa (B) 3.536 × 10
6
Pa
(C) 1.25 × 10
6
Pa (D) 1.25 × 10
5
Pa
Official Ans. by NTA (B)
Sol.
7
1
P 2 10 Pa ??
P
1
V
1
= P
2
V
2
Since V
2
= 2V
1
Hence P
2
= P
1
/2 (isothermal
expansion)
7
2
P 1 10 Pa ??
2 2 3 2
P (V ) P (2V )
??
?
7
6
3
1.5
1 10
P 3.536 10
2
?
? ? ?
8. Following statements are given :
(1) The average kinetic energy of a gas molecule
decreases when the temperature is reduced.
(2) The average kinetic energy of a gas molecule
increases with increase in pressure at constant
temperature.
(3) The average kinetic energy of a gas molecule
decreases with increases in volume.
(4) Pressure of a gas increases with increase in
temperature at constant pressure.
(5) The volume of gas decreases with increase in
temperature.
Choose the correct answer from the options given
below :
(A) (1) and (4) only (B) (1), (2) and (4) only
(C) (2) and (4) only (D) (1), (2) and (5) only
Official Ans. by NTA (A)
Sol.
avg
3
KE KT
2
?
2
rms
1
PV
3
??
Note : Statement (4) is correct only if we
consider it at constant volume and not constant
pressure. Ideally, this question must be bonus
but most appropriate answer is option (A)
3
9. In figure (A), mass ‘2 m’ is fixed on mass ‘m’
which is attached to two springs of spring constant
k. In figure (B), mass ‘m’ is attached to two spring
of spring constant ‘k’ and ‘2k’. If mass ‘m’ in (A)
and (B) are displaced by distance ‘x’ horizontally
and then released, then time period T
1
and T
2
corresponding to (A) and (B) respectively follow
the relation.
(A)
1
2
T 3
T
2
? (B)
1
2
T 3
T2
?
(C)
1
2
T 2
T3
? (D)
1
2
T 2
T3
?
Official Ans. by NTA (A)
Sol.
1
3m
T2
2k
??
2
m
T2
3k
??
1
2
3m
2
T 3
2k
T
m2
2
3k
?
??
?
10. A condenser of 2 ?F capacitance is charged
steadily from 0 to 5C. Which of the following
graph represents correctly the variation of potential
difference (V) across it’s plates with respect to the
charge (Q) on the condenser ?
(A) (B)
(C) (D)
Official Ans. by NTA (A)
Sol. Q = CV
1
VQ
C
?
Straight line with slope =
1
C
Slope
5
6
11
5 10
C 2 10
?
? ? ? ?
?
11. Two charged particles, having same kinetic energy,
are allowed to pass through a uniform magnetic
field perpendicular to the direction of motion. If
the ratio of radii of their circular paths is 6 : 5 and
their respective masses ratio is 9 : 4. Then, the ratio
of their charges will be :
(A) 8 : 5 (B) 5 : 4
(C) 5 : 3 (D) 8 : 7
Official Ans. by NTA (B)
Sol. Radius of circular path
2mk
R
qB
?
2mk
q
RB
?
1 1 2
2 2 1
q m R 9 5 5
q m R 4 6 4
? ? ? ? ?
12. To increase the resonant frequency in series LCR
circuit,
(A) Source frequency should be increased
(B) Another resistance should be added in series
with the first resistance.
(C) Another capacitor should be added in series
with the first capacitor
(D) The source frequency should be decreased
Official Ans. by NTA (C)
Sol.
1
f
2 LC
?
?
To increase the resonating frequency product of L
and C should decrease.
By joining capacitor in series, capacitor will
decrease
4
13. A small square loop of wire of side l is placed
inside a large square loop of wire L (L >> l). Both
loops are coplanar and their centres coincide at
point O as shown in figure. The mutual inductance
of the system is :
(A)
2
0
2 2 L ?
?
(B)
2
0
2 2 L
?
?
(C)
2
0
22
L
?
?
(D)
2
0
L
22
?
?
Official Ans. by NTA (C)
Sol. Assuming current I in outer loop magnetic field at
centre
00
i 2 2 i
4 (2sin45 )
L
L
4
2
??
? ? ? ? ?
?
??
l
l
Flux through inner loop
M
i
?
2
0
22
M
L
?
?
?
14. The rms value of conduction current in a parallel
plate capacitor is 6.9 ?A. The capacity of this
capacitor, if it is connected to 230 V ac supply with
an angular frequency of 600 rad/s, will be :
(A) 5 pF (B) 50 pF
(C) 100 pF (D) 200 pF
Official Ans. by NTA (B)
Sol. Current in capacitor
C
V
I
X
?
? ? ? ? I V C ? ? ?
6
I 6.9 10
C 50pF
V 230 600
?
?
? ? ?
??
15. Which of the following statement is correct ?
(A) In primary rainbow, observer sees red colour
on the top and violet on the bottom
(B) In primary rainbow, observer sees violet colour
on the top and red on the bottom
(C) In primary rainbow, light wave suffers total
internal reflection twice before coming out of
water drops
(D) Primary rainbow is less bright than secondary
rainbow.
Official Ans. by NTA (A)
Sol. In primary rainbow, red colour is at top and violet
is at bottom.
Intensity of secondary rainbow is less in
comparison to primary rainbow.
16. Time taken by light to travel in two different
materials A and B of refractive indices ?
A
and ?
B
of same thickness is t
1
and t
2
respectively. If
t
2
– t
1
= 5 × 10
-10
s and the ratio of ?
A
to ?
B
is 1 : 2.
Then the thickness of material, in meter is : (Given
v
A
and v
B
are velocities of light in A and B
materials respectively).
(A) 5 × 10
-10
v
a
m (B) 5 × 10
-10
m
(C) (D) 5 × 10
-10
v
B
m
Official Ans. by NTA (A)
Sol.
A A B
B B A
c / V V 1
c / V V 2
?
? ? ?
?
Let the thickness is d
10
BA
dd
5 10
vv
?
? ? ?
10
AB
AB
5 10 v v
d
vv
?
??
?
?
As v
A
= 2v
B
? d = 5 × 10
-10
× 2v
B
Or d = 5 × 10
-10
× v
A
5
17. A metal exposed to light of wavelength 800 nm
and emits photoelectrons with a certain kinetic
energy. The maximum kinetic energy of
photo-electron doubles when light of wavelength
500 nm is used. The work function of the metal is
(Take hc = 1230 eV-nm).
(A) 1.537 eV (B) 2.46 eV
(C) 0.615 eV (D) 1.23 eV
Official Ans. by NTA (C)
Sol.
1
1230
k
800
? ? ? …(1)
21
1230
k 2k
500
?? - ? …(2)
Eliminating k
1
from (1) and (2) we get
1230 1230
0
500 400
? ? ? ?
0.615eV ??
18. The momentum of an electron revolving in n
th
orbit
is given by : (Symbols have their usual meanings)
(A)
nh
2r ?
(B)
nh
2r
(C)
nh
2 ?
(D)
2r
nh
?
Official Ans. by NTA (A)
Sol. Angular momentum is integral multiple of
h
2 ?
mvr =
nh
2 ?
So momentum mv =
nh
2r ?
19. The magnetic moment of an electron (e) revolving
in an orbit around nucleus with an orbital angular
momentum is given by :
(A)
L
eL
2m
?? (B)
L
eL
2m
? ? ?
(C)
l
eL
m
? ? ? (D)
l
2eL
m
??
Official Ans. by NTA (B)
Sol. Ratio of magnetic moment and angular momentum
q
2m L
?
?
For e
–
e
L
2m
? ? ?
20. In the circuit, the logical value of A = 1 or B = 1
when potential at A or B is 5V and the logical value
of A = 0 or B = 0 when potential at A or B is 0 V.
The truth table of the given circuit will be :
(A)
A B Y
000
1 0 0
0 1 0
111
(B)
A B Y
000
1 0 1
0 1 1
111
(C)
A B Y
000
1 0 0
0 1 0
1 1 0
(D)
A B Y
0 0 1
1 0 1
0 1 1
1 1 0
Official Ans. by NTA (A)
Sol. When both A and B have logical value ‘1’ both
diode are reverse bias and current will flow in
resistor hence output will be 5 volt i.e. logical
value ‘1’.
In all other case conduction will take place, hence
output will be zero volt i.e. logical value ‘0’.
So truth table is
A B Y
000
0 1 0
1 0 0
111
(AND gate)
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