JEE Main 2023 January 24 Shift 1 Paper & Solutions | Mock Tests for JEE Main and Advanced 2025 PDF Download

 Page 1


SECTION - A 
1. A circular loop of radius ?? is carrying current I A. The ratio of magnetic field at the center of circular 
loop and at a distance ?? from the center of the loop on its axis is: 
 (1) 2 v 2 : 1 (2) 1 : 3 v 2 (3) 1 : v 2  (4) 3 v 2 : 2 
Sol.  1 
 Magnetic field at centre of coil 
 on the axis at x = r ?  
  
 
 
 
2.  The weight of a body at the surface of earth is 18 N. The weight of the body at an altitude of 3200 km 
above the earth's surface is (given, radius of earth ?? ?? = 6400 km ): 
(1) 8 N (2) 4 . 9 N (3) 9 . 8 N  (4) 19 . 6 N 
Sol. 1 
 Weight on earth surface W = mg = 18 N 
 Above earth surface ?  
 h = 3200 km = R/2 
  
 
 
3. Two long straight wires ?? and ?? carrying equal current 10 A each were kept parallel to each other at 
5 cm distance. Magnitude of magnetic force experienced by 10 cm length of wire P is ?? 1
 - If distance 
between wires is halved and currents on them are doubled, force ?? 2
 on 10 cm length of wire P will be: 
(1) 
?? 1
8
 (2) 8 F
1
 (3) 10 F
1
  (4) 
?? 1
10
 
Sol. 2 
  
 ? = 10 cm (Both) ? 
  
??
??
??
??
? ? ? ? ?
??
??
??
F 8F
F 2I 5 F 8
2
I1 FF
5
22
11
21
2
r
? 
I
F
2
? ? ?
?? 2 r 2 r
?? I I I
FF
2
0 1 2 0
9
? ? ? ? 
4
W 18 W 8 N
22
??
??
? ? ?
?? 3R
2
9
GM 4
W m W mg
22 2
? (R h)
?
GM
Wm
2 2
B
? 
B
22
2
1
? 
2(2 2 r)
? I
B
0
2
?
? 2 r r
? Ir
B
22 2
0
2 3
2
? ?
?
? 2 r x
? Ir
B
22 2
0
2 3
2
? ?
? 
2r
? I
B
0
1
JEE –MAIN EXAMINATION – JANUARY, 2023 
(Held On Thursday 24th January, 2023) TIME : 9 : 00 AM to 12 : 00 NOON 
 
Page 2


SECTION - A 
1. A circular loop of radius ?? is carrying current I A. The ratio of magnetic field at the center of circular 
loop and at a distance ?? from the center of the loop on its axis is: 
 (1) 2 v 2 : 1 (2) 1 : 3 v 2 (3) 1 : v 2  (4) 3 v 2 : 2 
Sol.  1 
 Magnetic field at centre of coil 
 on the axis at x = r ?  
  
 
 
 
2.  The weight of a body at the surface of earth is 18 N. The weight of the body at an altitude of 3200 km 
above the earth's surface is (given, radius of earth ?? ?? = 6400 km ): 
(1) 8 N (2) 4 . 9 N (3) 9 . 8 N  (4) 19 . 6 N 
Sol. 1 
 Weight on earth surface W = mg = 18 N 
 Above earth surface ?  
 h = 3200 km = R/2 
  
 
 
3. Two long straight wires ?? and ?? carrying equal current 10 A each were kept parallel to each other at 
5 cm distance. Magnitude of magnetic force experienced by 10 cm length of wire P is ?? 1
 - If distance 
between wires is halved and currents on them are doubled, force ?? 2
 on 10 cm length of wire P will be: 
(1) 
?? 1
8
 (2) 8 F
1
 (3) 10 F
1
  (4) 
?? 1
10
 
Sol. 2 
  
 ? = 10 cm (Both) ? 
  
??
??
??
??
? ? ? ? ?
??
??
??
F 8F
F 2I 5 F 8
2
I1 FF
5
22
11
21
2
r
? 
I
F
2
? ? ?
?? 2 r 2 r
?? I I I
FF
2
0 1 2 0
9
? ? ? ? 
4
W 18 W 8 N
22
??
??
? ? ?
?? 3R
2
9
GM 4
W m W mg
22 2
? (R h)
?
GM
Wm
2 2
B
? 
B
22
2
1
? 
2(2 2 r)
? I
B
0
2
?
? 2 r r
? Ir
B
22 2
0
2 3
2
? ?
?
? 2 r x
? Ir
B
22 2
0
2 3
2
? ?
? 
2r
? I
B
0
1
JEE –MAIN EXAMINATION – JANUARY, 2023 
(Held On Thursday 24th January, 2023) TIME : 9 : 00 AM to 12 : 00 NOON 
 
4. Given below are two statements : 
Statement I : The temperature of a gas is - 73
°
C. When the gas is heated to 527
°
C, the root mean 
square speed of the molecules is doubled. 
Statement II : The product of pressure and volume of an ideal gas will be equal to translational kinetic 
energy of the molecules. 
In the light of the above statements, choose the correct answer from the options given below: 
(1) Statement I is false but Statement II is true 
(2) Both Statement I and Statement II are false 
(3) Statement I is true but Statement II is false 
(4) Both Statement I and Statement II are true 
Sol. 3 
 Statements-1 
 
1
rms rms
v T v 273 – 73 ? ? ? 
           
2
rms
v 273 527 ?? 
 
1
21
2
rms
rms rms
rms
v
00
v 2v
v 800
?
? ? ?  (True) 
 Statements-2 
 Translation K.E. = 
33
nRT PV
22
?  (False) 
 
5. The maximum vertical height to which a man can throw a ball is 136 m. The maximum horizontal 
distance upto which he can throw the same ball is: 
(1) 272 m (2) 68 m (3) 192 m  (4) 136 m 
Sol. 1 
 Max vertical height H = 
2
v
136m
2g
? 
 Max horizontal distance R = 
2
v
g
 ? ?R = 2 × 136 = 272 m 
 
6. Given below are two statements : 
Statement I : If the Brewster's angle for the light propagating from air to glass is ?? B
, then the 
Brewster's angle for the light propagating from glass to air is 
?? 2
- ?? ?? 
Statement II : The Brewster's angle for the light propagating from glass to air is tan
- 1
? ( ?? g
) where ?? g
 is 
the refractive index of glass. 
In the light of the above statements, choose the correct answer from the options given below: 
 (1) Both Statement I and Statement II are false 
 (2) Statement I is true but Statement II is false 
 (3) Statement I is false but Statement II is true 
 (4) Both Statement I and Statement II are true 
 
Page 3


SECTION - A 
1. A circular loop of radius ?? is carrying current I A. The ratio of magnetic field at the center of circular 
loop and at a distance ?? from the center of the loop on its axis is: 
 (1) 2 v 2 : 1 (2) 1 : 3 v 2 (3) 1 : v 2  (4) 3 v 2 : 2 
Sol.  1 
 Magnetic field at centre of coil 
 on the axis at x = r ?  
  
 
 
 
2.  The weight of a body at the surface of earth is 18 N. The weight of the body at an altitude of 3200 km 
above the earth's surface is (given, radius of earth ?? ?? = 6400 km ): 
(1) 8 N (2) 4 . 9 N (3) 9 . 8 N  (4) 19 . 6 N 
Sol. 1 
 Weight on earth surface W = mg = 18 N 
 Above earth surface ?  
 h = 3200 km = R/2 
  
 
 
3. Two long straight wires ?? and ?? carrying equal current 10 A each were kept parallel to each other at 
5 cm distance. Magnitude of magnetic force experienced by 10 cm length of wire P is ?? 1
 - If distance 
between wires is halved and currents on them are doubled, force ?? 2
 on 10 cm length of wire P will be: 
(1) 
?? 1
8
 (2) 8 F
1
 (3) 10 F
1
  (4) 
?? 1
10
 
Sol. 2 
  
 ? = 10 cm (Both) ? 
  
??
??
??
??
? ? ? ? ?
??
??
??
F 8F
F 2I 5 F 8
2
I1 FF
5
22
11
21
2
r
? 
I
F
2
? ? ?
?? 2 r 2 r
?? I I I
FF
2
0 1 2 0
9
? ? ? ? 
4
W 18 W 8 N
22
??
??
? ? ?
?? 3R
2
9
GM 4
W m W mg
22 2
? (R h)
?
GM
Wm
2 2
B
? 
B
22
2
1
? 
2(2 2 r)
? I
B
0
2
?
? 2 r r
? Ir
B
22 2
0
2 3
2
? ?
?
? 2 r x
? Ir
B
22 2
0
2 3
2
? ?
? 
2r
? I
B
0
1
JEE –MAIN EXAMINATION – JANUARY, 2023 
(Held On Thursday 24th January, 2023) TIME : 9 : 00 AM to 12 : 00 NOON 
 
4. Given below are two statements : 
Statement I : The temperature of a gas is - 73
°
C. When the gas is heated to 527
°
C, the root mean 
square speed of the molecules is doubled. 
Statement II : The product of pressure and volume of an ideal gas will be equal to translational kinetic 
energy of the molecules. 
In the light of the above statements, choose the correct answer from the options given below: 
(1) Statement I is false but Statement II is true 
(2) Both Statement I and Statement II are false 
(3) Statement I is true but Statement II is false 
(4) Both Statement I and Statement II are true 
Sol. 3 
 Statements-1 
 
1
rms rms
v T v 273 – 73 ? ? ? 
           
2
rms
v 273 527 ?? 
 
1
21
2
rms
rms rms
rms
v
00
v 2v
v 800
?
? ? ?  (True) 
 Statements-2 
 Translation K.E. = 
33
nRT PV
22
?  (False) 
 
5. The maximum vertical height to which a man can throw a ball is 136 m. The maximum horizontal 
distance upto which he can throw the same ball is: 
(1) 272 m (2) 68 m (3) 192 m  (4) 136 m 
Sol. 1 
 Max vertical height H = 
2
v
136m
2g
? 
 Max horizontal distance R = 
2
v
g
 ? ?R = 2 × 136 = 272 m 
 
6. Given below are two statements : 
Statement I : If the Brewster's angle for the light propagating from air to glass is ?? B
, then the 
Brewster's angle for the light propagating from glass to air is 
?? 2
- ?? ?? 
Statement II : The Brewster's angle for the light propagating from glass to air is tan
- 1
? ( ?? g
) where ?? g
 is 
the refractive index of glass. 
In the light of the above statements, choose the correct answer from the options given below: 
 (1) Both Statement I and Statement II are false 
 (2) Statement I is true but Statement II is false 
 (3) Statement I is false but Statement II is true 
 (4) Both Statement I and Statement II are true 
 
Sol. 2 
 
 
 
? B air 
? B 
r 
 
B
r
2
?
? ? ?
 
B
r–
2
?
??
r 
r 
Glass  
Glass 
? g 
air 
? B 
True 
 
 For glass to air 
 
 
 
 
Glass  
air 
r 
i B i B 
 
 
gB
sini 1 ·sin r ?? 
 
B
ri
2
?
?? 
 
g B B B
g
1
sin i cosi tan i ? ? ? ?
?
? ?i B = tan
– 1
 
g
1
??
??
??
?
??
 
 
7. A 100 m long wire having cross-sectional area 6 . 25 × 10
- 4
 m
2
 and Young's modulus is 10
10
Nm
- 2
 is 
subjected to a load of 250 N, then the elongation in the wire will be: 
(1) 4 × 10
- 3
 m (2) 6 . 25 × 10
- 3
 m (3) 6 . 25 × 10
- 6
 m (4) 4 × 10
- 4
 m 
Sol. 1 
 Stress = y strain ? 
W
y
A
?
? 
 
10 –4
W 250 100
yA 10 6.25 10
?
? ? ? ? ?
??
 
 ? ? = 4 × 10
–3
 m 
 
 
8. If two charges q 1 and q 2 are separated with distance 'd' and placed in a medium of dielectric constant 
K. What will be the equivalent distance between charges in air for the same electrostatic force? 
 (1) 2d k (2) 1.5 d k (3) d k (4) k d 
Page 4


SECTION - A 
1. A circular loop of radius ?? is carrying current I A. The ratio of magnetic field at the center of circular 
loop and at a distance ?? from the center of the loop on its axis is: 
 (1) 2 v 2 : 1 (2) 1 : 3 v 2 (3) 1 : v 2  (4) 3 v 2 : 2 
Sol.  1 
 Magnetic field at centre of coil 
 on the axis at x = r ?  
  
 
 
 
2.  The weight of a body at the surface of earth is 18 N. The weight of the body at an altitude of 3200 km 
above the earth's surface is (given, radius of earth ?? ?? = 6400 km ): 
(1) 8 N (2) 4 . 9 N (3) 9 . 8 N  (4) 19 . 6 N 
Sol. 1 
 Weight on earth surface W = mg = 18 N 
 Above earth surface ?  
 h = 3200 km = R/2 
  
 
 
3. Two long straight wires ?? and ?? carrying equal current 10 A each were kept parallel to each other at 
5 cm distance. Magnitude of magnetic force experienced by 10 cm length of wire P is ?? 1
 - If distance 
between wires is halved and currents on them are doubled, force ?? 2
 on 10 cm length of wire P will be: 
(1) 
?? 1
8
 (2) 8 F
1
 (3) 10 F
1
  (4) 
?? 1
10
 
Sol. 2 
  
 ? = 10 cm (Both) ? 
  
??
??
??
??
? ? ? ? ?
??
??
??
F 8F
F 2I 5 F 8
2
I1 FF
5
22
11
21
2
r
? 
I
F
2
? ? ?
?? 2 r 2 r
?? I I I
FF
2
0 1 2 0
9
? ? ? ? 
4
W 18 W 8 N
22
??
??
? ? ?
?? 3R
2
9
GM 4
W m W mg
22 2
? (R h)
?
GM
Wm
2 2
B
? 
B
22
2
1
? 
2(2 2 r)
? I
B
0
2
?
? 2 r r
? Ir
B
22 2
0
2 3
2
? ?
?
? 2 r x
? Ir
B
22 2
0
2 3
2
? ?
? 
2r
? I
B
0
1
JEE –MAIN EXAMINATION – JANUARY, 2023 
(Held On Thursday 24th January, 2023) TIME : 9 : 00 AM to 12 : 00 NOON 
 
4. Given below are two statements : 
Statement I : The temperature of a gas is - 73
°
C. When the gas is heated to 527
°
C, the root mean 
square speed of the molecules is doubled. 
Statement II : The product of pressure and volume of an ideal gas will be equal to translational kinetic 
energy of the molecules. 
In the light of the above statements, choose the correct answer from the options given below: 
(1) Statement I is false but Statement II is true 
(2) Both Statement I and Statement II are false 
(3) Statement I is true but Statement II is false 
(4) Both Statement I and Statement II are true 
Sol. 3 
 Statements-1 
 
1
rms rms
v T v 273 – 73 ? ? ? 
           
2
rms
v 273 527 ?? 
 
1
21
2
rms
rms rms
rms
v
00
v 2v
v 800
?
? ? ?  (True) 
 Statements-2 
 Translation K.E. = 
33
nRT PV
22
?  (False) 
 
5. The maximum vertical height to which a man can throw a ball is 136 m. The maximum horizontal 
distance upto which he can throw the same ball is: 
(1) 272 m (2) 68 m (3) 192 m  (4) 136 m 
Sol. 1 
 Max vertical height H = 
2
v
136m
2g
? 
 Max horizontal distance R = 
2
v
g
 ? ?R = 2 × 136 = 272 m 
 
6. Given below are two statements : 
Statement I : If the Brewster's angle for the light propagating from air to glass is ?? B
, then the 
Brewster's angle for the light propagating from glass to air is 
?? 2
- ?? ?? 
Statement II : The Brewster's angle for the light propagating from glass to air is tan
- 1
? ( ?? g
) where ?? g
 is 
the refractive index of glass. 
In the light of the above statements, choose the correct answer from the options given below: 
 (1) Both Statement I and Statement II are false 
 (2) Statement I is true but Statement II is false 
 (3) Statement I is false but Statement II is true 
 (4) Both Statement I and Statement II are true 
 
Sol. 2 
 
 
 
? B air 
? B 
r 
 
B
r
2
?
? ? ?
 
B
r–
2
?
??
r 
r 
Glass  
Glass 
? g 
air 
? B 
True 
 
 For glass to air 
 
 
 
 
Glass  
air 
r 
i B i B 
 
 
gB
sini 1 ·sin r ?? 
 
B
ri
2
?
?? 
 
g B B B
g
1
sin i cosi tan i ? ? ? ?
?
? ?i B = tan
– 1
 
g
1
??
??
??
?
??
 
 
7. A 100 m long wire having cross-sectional area 6 . 25 × 10
- 4
 m
2
 and Young's modulus is 10
10
Nm
- 2
 is 
subjected to a load of 250 N, then the elongation in the wire will be: 
(1) 4 × 10
- 3
 m (2) 6 . 25 × 10
- 3
 m (3) 6 . 25 × 10
- 6
 m (4) 4 × 10
- 4
 m 
Sol. 1 
 Stress = y strain ? 
W
y
A
?
? 
 
10 –4
W 250 100
yA 10 6.25 10
?
? ? ? ? ?
??
 
 ? ? = 4 × 10
–3
 m 
 
 
8. If two charges q 1 and q 2 are separated with distance 'd' and placed in a medium of dielectric constant 
K. What will be the equivalent distance between charges in air for the same electrostatic force? 
 (1) 2d k (2) 1.5 d k (3) d k (4) k d 
Sol. 3 
 For same force  
 
1 2 1 2
22
00
q q q q
r d K
4 kd 4 r
? ? ?
? ? ? ?
 
 
9.  Consider the following radioactive decay process 
  
 
The mass number and the atomic number of A
6
 are given by: 
(1) 210 and 84 (2) 210 and 82 (3) 211 and 80 (4) 210 and 80 
Sol. 4 
 
218 214 214 214 210 210 210
84 82 1 83 2 83 3 81 4 80 5 80 6
A A A A A A A
??
? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 
 
10. From the photoelectric effect experiment, following observations are made. Identify which of these 
are correct. 
A. The stopping potential depends only on the work function of the metal. 
B. The saturation current increases as the intensity of incident light increases. 
C. The maximum kinetic energy of a photo electron depends on the intensity of the incident light. 
D. Photoelectric effect can be explained using wave theory of light. 
Choose the correct answer from the options given below: 
(1) A, C, D only (2) B, C only (3) B only (4) A, B, D only 
Sol. 3 
 
sp
h–
v
e
??
? ( ? and ? both) 
 Intensity ? current ? 
 kE max = h? – ? 
 Photoelectric effect is not explained by wave theory 
 
11.  Given below are two statements: 
Statement I: An elevator can go up or down with uniform speed when its weight is balanced with the 
tension of its cable. 
Statement II: Force exerted by the floor of an elevator on the foot of a person standing on it is more 
than his/her weight when the elevator goes down with increasing speed. 
In the light of the above statements, choose the correct answer from the options given below: 
(1) Both Statement I and Statement II are true 
(2) Statement I is false but Statement II is true 
(3) Statement I is true but Statement II is false 
(4) Both Statement I and Statement II are false 
Page 5


SECTION - A 
1. A circular loop of radius ?? is carrying current I A. The ratio of magnetic field at the center of circular 
loop and at a distance ?? from the center of the loop on its axis is: 
 (1) 2 v 2 : 1 (2) 1 : 3 v 2 (3) 1 : v 2  (4) 3 v 2 : 2 
Sol.  1 
 Magnetic field at centre of coil 
 on the axis at x = r ?  
  
 
 
 
2.  The weight of a body at the surface of earth is 18 N. The weight of the body at an altitude of 3200 km 
above the earth's surface is (given, radius of earth ?? ?? = 6400 km ): 
(1) 8 N (2) 4 . 9 N (3) 9 . 8 N  (4) 19 . 6 N 
Sol. 1 
 Weight on earth surface W = mg = 18 N 
 Above earth surface ?  
 h = 3200 km = R/2 
  
 
 
3. Two long straight wires ?? and ?? carrying equal current 10 A each were kept parallel to each other at 
5 cm distance. Magnitude of magnetic force experienced by 10 cm length of wire P is ?? 1
 - If distance 
between wires is halved and currents on them are doubled, force ?? 2
 on 10 cm length of wire P will be: 
(1) 
?? 1
8
 (2) 8 F
1
 (3) 10 F
1
  (4) 
?? 1
10
 
Sol. 2 
  
 ? = 10 cm (Both) ? 
  
??
??
??
??
? ? ? ? ?
??
??
??
F 8F
F 2I 5 F 8
2
I1 FF
5
22
11
21
2
r
? 
I
F
2
? ? ?
?? 2 r 2 r
?? I I I
FF
2
0 1 2 0
9
? ? ? ? 
4
W 18 W 8 N
22
??
??
? ? ?
?? 3R
2
9
GM 4
W m W mg
22 2
? (R h)
?
GM
Wm
2 2
B
? 
B
22
2
1
? 
2(2 2 r)
? I
B
0
2
?
? 2 r r
? Ir
B
22 2
0
2 3
2
? ?
?
? 2 r x
? Ir
B
22 2
0
2 3
2
? ?
? 
2r
? I
B
0
1
JEE –MAIN EXAMINATION – JANUARY, 2023 
(Held On Thursday 24th January, 2023) TIME : 9 : 00 AM to 12 : 00 NOON 
 
4. Given below are two statements : 
Statement I : The temperature of a gas is - 73
°
C. When the gas is heated to 527
°
C, the root mean 
square speed of the molecules is doubled. 
Statement II : The product of pressure and volume of an ideal gas will be equal to translational kinetic 
energy of the molecules. 
In the light of the above statements, choose the correct answer from the options given below: 
(1) Statement I is false but Statement II is true 
(2) Both Statement I and Statement II are false 
(3) Statement I is true but Statement II is false 
(4) Both Statement I and Statement II are true 
Sol. 3 
 Statements-1 
 
1
rms rms
v T v 273 – 73 ? ? ? 
           
2
rms
v 273 527 ?? 
 
1
21
2
rms
rms rms
rms
v
00
v 2v
v 800
?
? ? ?  (True) 
 Statements-2 
 Translation K.E. = 
33
nRT PV
22
?  (False) 
 
5. The maximum vertical height to which a man can throw a ball is 136 m. The maximum horizontal 
distance upto which he can throw the same ball is: 
(1) 272 m (2) 68 m (3) 192 m  (4) 136 m 
Sol. 1 
 Max vertical height H = 
2
v
136m
2g
? 
 Max horizontal distance R = 
2
v
g
 ? ?R = 2 × 136 = 272 m 
 
6. Given below are two statements : 
Statement I : If the Brewster's angle for the light propagating from air to glass is ?? B
, then the 
Brewster's angle for the light propagating from glass to air is 
?? 2
- ?? ?? 
Statement II : The Brewster's angle for the light propagating from glass to air is tan
- 1
? ( ?? g
) where ?? g
 is 
the refractive index of glass. 
In the light of the above statements, choose the correct answer from the options given below: 
 (1) Both Statement I and Statement II are false 
 (2) Statement I is true but Statement II is false 
 (3) Statement I is false but Statement II is true 
 (4) Both Statement I and Statement II are true 
 
Sol. 2 
 
 
 
? B air 
? B 
r 
 
B
r
2
?
? ? ?
 
B
r–
2
?
??
r 
r 
Glass  
Glass 
? g 
air 
? B 
True 
 
 For glass to air 
 
 
 
 
Glass  
air 
r 
i B i B 
 
 
gB
sini 1 ·sin r ?? 
 
B
ri
2
?
?? 
 
g B B B
g
1
sin i cosi tan i ? ? ? ?
?
? ?i B = tan
– 1
 
g
1
??
??
??
?
??
 
 
7. A 100 m long wire having cross-sectional area 6 . 25 × 10
- 4
 m
2
 and Young's modulus is 10
10
Nm
- 2
 is 
subjected to a load of 250 N, then the elongation in the wire will be: 
(1) 4 × 10
- 3
 m (2) 6 . 25 × 10
- 3
 m (3) 6 . 25 × 10
- 6
 m (4) 4 × 10
- 4
 m 
Sol. 1 
 Stress = y strain ? 
W
y
A
?
? 
 
10 –4
W 250 100
yA 10 6.25 10
?
? ? ? ? ?
??
 
 ? ? = 4 × 10
–3
 m 
 
 
8. If two charges q 1 and q 2 are separated with distance 'd' and placed in a medium of dielectric constant 
K. What will be the equivalent distance between charges in air for the same electrostatic force? 
 (1) 2d k (2) 1.5 d k (3) d k (4) k d 
Sol. 3 
 For same force  
 
1 2 1 2
22
00
q q q q
r d K
4 kd 4 r
? ? ?
? ? ? ?
 
 
9.  Consider the following radioactive decay process 
  
 
The mass number and the atomic number of A
6
 are given by: 
(1) 210 and 84 (2) 210 and 82 (3) 211 and 80 (4) 210 and 80 
Sol. 4 
 
218 214 214 214 210 210 210
84 82 1 83 2 83 3 81 4 80 5 80 6
A A A A A A A
??
? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 
 
10. From the photoelectric effect experiment, following observations are made. Identify which of these 
are correct. 
A. The stopping potential depends only on the work function of the metal. 
B. The saturation current increases as the intensity of incident light increases. 
C. The maximum kinetic energy of a photo electron depends on the intensity of the incident light. 
D. Photoelectric effect can be explained using wave theory of light. 
Choose the correct answer from the options given below: 
(1) A, C, D only (2) B, C only (3) B only (4) A, B, D only 
Sol. 3 
 
sp
h–
v
e
??
? ( ? and ? both) 
 Intensity ? current ? 
 kE max = h? – ? 
 Photoelectric effect is not explained by wave theory 
 
11.  Given below are two statements: 
Statement I: An elevator can go up or down with uniform speed when its weight is balanced with the 
tension of its cable. 
Statement II: Force exerted by the floor of an elevator on the foot of a person standing on it is more 
than his/her weight when the elevator goes down with increasing speed. 
In the light of the above statements, choose the correct answer from the options given below: 
(1) Both Statement I and Statement II are true 
(2) Statement I is false but Statement II is true 
(3) Statement I is true but Statement II is false 
(4) Both Statement I and Statement II are false 
Sol. 3 
 Statement-1 
 When force balance it can move with uniform velocity (Uniform speed) True 
 Statement-2 
 Elevator going down with increasing speed means its acceleration is downwards 
 mg – N = ma (on person) 
 N = mg – ma  (False) 
 
12. 1 g of a liquid is converted to vapour at 3 × 10
5
 Pa pressure. If 10% of the heat supplied is used for 
increasing the volume by 1600 cm
3
 during this phase change, then the increase in internal energy in 
the process will be: 
 (1) 432000 J (2) 4320 J (3) 4800 J (4) 4 . 32 × 10
8
 J 
Sol. 2 
 10% of ?Q = P ?V (W/D by gas) 
 
5 –6
Q
3 10 (1600 10 )
10
?
? ? ? 
 ?Q = 4800 J 
 Using first law of the thermodynamics 
 ?Q = ?u + W 
 ?Q = ?u + 
Q9
uQ
10 10
?
? ? ? ? 
 
9
u 4800 u 4320J
10
? ? ? ? ? ? 
 
13.  As shown in the figure, a network of resistors is connected to a battery of 24 V with an internal 
resistance of 3O. The currents through the resistors ?? 4
 and ?? 5
 are ?? 4
 and ?? 5
 respectively. The values of 
I
4
 and I
5
 are: 
 
 
(24 V , 3 ?) 
 
? (1) I
4
=
2
5
 A and I
5
=
8
5
 A (2) I
4
=
24
5
 A and I
5
=
6
5
 A 
 (3) I
4
=
8
5
 A and I
5
=
2
5
 A (4) I
4
=
6
5
 A and I
5
=
24
5
 A 
 
Sol. 1