JEE Main Previous Year Questions (2025): Thermal Properties of Matter

 Page 1


JEE Main Previous Year Questions 
(2025): Thermal Properties of Matter 
 
Q1: Which of the following figure represents the relation between Celsius and 
Fahrenheit temperatures ? 
A.  
B.  
C.  
D.  
Ans: D 
Solution: 
?? 5
=
F - 32
9
? C =
5F
9
-
160
9
 
Page 2


JEE Main Previous Year Questions 
(2025): Thermal Properties of Matter 
 
Q1: Which of the following figure represents the relation between Celsius and 
Fahrenheit temperatures ? 
A.  
B.  
C.  
D.  
Ans: D 
Solution: 
?? 5
=
F - 32
9
? C =
5F
9
-
160
9
 
 
Q2: An amount of ice of mass ????
-?? ???? and temperature -????
°
?? is transformed to 
vapour of temperature ??????
°
?? by applying heat. The total amount of work required for 
this conversion is, (Take, specific heat of ice = ???????? ?????? -?? ?? -?? , specific heat of water 
= ???????? ?????? -?? ?? -?? , specific heat of steam = ???????? ?????? -?? ?? -?? , Latent heat of ice =
?? . ???? × ????
?? ?????? -?? and Latent heat of steam = ?? . ???? × ????
?? ?????? -?? ) 
A. 3043 J 
B. 3024 J 
C. 3003 J 
D. 3022 J 
Ans: A 
Solution: 
 
??? 1
= m × S
1
× ?T = 10
-3
× 2100× 10 = 21 J
??? 2
= m × L
f
= 10
-3
× 3.35 × 10
5
= 335 J
??? 3
= m × S
w
× ?T = 10
-3
× 4180× 100 = 418 J
?Q
4
= m × L
v
= 10
-3
× 2.25 × 10
6
= 2250 J
?Q
5
= m × S
v
× ?T = 10
-3
× 1920 × 10 = 19.2 J
?Q
net 
= 3043.2 J
 
Page 3


JEE Main Previous Year Questions 
(2025): Thermal Properties of Matter 
 
Q1: Which of the following figure represents the relation between Celsius and 
Fahrenheit temperatures ? 
A.  
B.  
C.  
D.  
Ans: D 
Solution: 
?? 5
=
F - 32
9
? C =
5F
9
-
160
9
 
 
Q2: An amount of ice of mass ????
-?? ???? and temperature -????
°
?? is transformed to 
vapour of temperature ??????
°
?? by applying heat. The total amount of work required for 
this conversion is, (Take, specific heat of ice = ???????? ?????? -?? ?? -?? , specific heat of water 
= ???????? ?????? -?? ?? -?? , specific heat of steam = ???????? ?????? -?? ?? -?? , Latent heat of ice =
?? . ???? × ????
?? ?????? -?? and Latent heat of steam = ?? . ???? × ????
?? ?????? -?? ) 
A. 3043 J 
B. 3024 J 
C. 3003 J 
D. 3022 J 
Ans: A 
Solution: 
 
??? 1
= m × S
1
× ?T = 10
-3
× 2100× 10 = 21 J
??? 2
= m × L
f
= 10
-3
× 3.35 × 10
5
= 335 J
??? 3
= m × S
w
× ?T = 10
-3
× 4180× 100 = 418 J
?Q
4
= m × L
v
= 10
-3
× 2.25 × 10
6
= 2250 J
?Q
5
= m × S
v
× ?T = 10
-3
× 1920 × 10 = 19.2 J
?Q
net 
= 3043.2 J
 
 
Q3: A gun fires a lead bullet of temperature 300 K into a wooden block. The bullet 
having melting temperature of 600 K penetrates into the block and melts down. If the 
total heat required for the process is 625 J , then the mass of the bullet is ____ grams. 
(Latent heat of fusion of lead = ?? . ?? × ????
?? ?????? -?? and specific heat capacity of lead =
?????? ?????? -?? ?? -?? ) 
A. 10 
B. 20 
C. 5 
D. 15 
Ans: A 
Solution: 
 
Q4: Three conductors of same length having thermal conductivity ?? ?? , ?? ?? and ?? ?? are 
connected as shown in figure. 
 
Area of cross sections of ?? st 
 and ?? nd 
 conductor are same and for ?? rd 
 conductor it is 
double of the ?? st 
 conductor. The temperatures are given in the figure. In steady state 
Page 4


JEE Main Previous Year Questions 
(2025): Thermal Properties of Matter 
 
Q1: Which of the following figure represents the relation between Celsius and 
Fahrenheit temperatures ? 
A.  
B.  
C.  
D.  
Ans: D 
Solution: 
?? 5
=
F - 32
9
? C =
5F
9
-
160
9
 
 
Q2: An amount of ice of mass ????
-?? ???? and temperature -????
°
?? is transformed to 
vapour of temperature ??????
°
?? by applying heat. The total amount of work required for 
this conversion is, (Take, specific heat of ice = ???????? ?????? -?? ?? -?? , specific heat of water 
= ???????? ?????? -?? ?? -?? , specific heat of steam = ???????? ?????? -?? ?? -?? , Latent heat of ice =
?? . ???? × ????
?? ?????? -?? and Latent heat of steam = ?? . ???? × ????
?? ?????? -?? ) 
A. 3043 J 
B. 3024 J 
C. 3003 J 
D. 3022 J 
Ans: A 
Solution: 
 
??? 1
= m × S
1
× ?T = 10
-3
× 2100× 10 = 21 J
??? 2
= m × L
f
= 10
-3
× 3.35 × 10
5
= 335 J
??? 3
= m × S
w
× ?T = 10
-3
× 4180× 100 = 418 J
?Q
4
= m × L
v
= 10
-3
× 2.25 × 10
6
= 2250 J
?Q
5
= m × S
v
× ?T = 10
-3
× 1920 × 10 = 19.2 J
?Q
net 
= 3043.2 J
 
 
Q3: A gun fires a lead bullet of temperature 300 K into a wooden block. The bullet 
having melting temperature of 600 K penetrates into the block and melts down. If the 
total heat required for the process is 625 J , then the mass of the bullet is ____ grams. 
(Latent heat of fusion of lead = ?? . ?? × ????
?? ?????? -?? and specific heat capacity of lead =
?????? ?????? -?? ?? -?? ) 
A. 10 
B. 20 
C. 5 
D. 15 
Ans: A 
Solution: 
 
Q4: Three conductors of same length having thermal conductivity ?? ?? , ?? ?? and ?? ?? are 
connected as shown in figure. 
 
Area of cross sections of ?? st 
 and ?? nd 
 conductor are same and for ?? rd 
 conductor it is 
double of the ?? st 
 conductor. The temperatures are given in the figure. In steady state 
condition, the value of ?? is ____  
°
?? . 
(Given : ?? ?? = ???? ????
-?? ?? -?? ?? -?? , ?? ?? = ?????? ????
-?? ?? -?? ?? -?? , ?? ?? = ?????? ????
-?? ?? -?? ?? -?? ) 
Ans: 40 
Solution: 
 
R
1
=
2L
K
1
A
R
2
=
2L
K
2
A
R
3
=
L
K
3
A
?? - 100
R
1
R
2
R
1
+ R
2
+
?? - 0
R
3
= 0
?? = 40
 
Q5: Two spherical bodies of same materials having radii 0.2 m and 0.8 m are placed in 
same atmosphere. The temperature of the smaller body is 800 K and temperature of 
the bigger body is 400 K . If the energy radiated from the smaller body is E , the energy 
radiated from the bigger body is (assume, effect of the surrounding temperature to be 
negligible) 
A. 16 E 
B. ?? 
C. 64 E 
D. 256 E 
Ans: B 
Solution:  
Page 5


JEE Main Previous Year Questions 
(2025): Thermal Properties of Matter 
 
Q1: Which of the following figure represents the relation between Celsius and 
Fahrenheit temperatures ? 
A.  
B.  
C.  
D.  
Ans: D 
Solution: 
?? 5
=
F - 32
9
? C =
5F
9
-
160
9
 
 
Q2: An amount of ice of mass ????
-?? ???? and temperature -????
°
?? is transformed to 
vapour of temperature ??????
°
?? by applying heat. The total amount of work required for 
this conversion is, (Take, specific heat of ice = ???????? ?????? -?? ?? -?? , specific heat of water 
= ???????? ?????? -?? ?? -?? , specific heat of steam = ???????? ?????? -?? ?? -?? , Latent heat of ice =
?? . ???? × ????
?? ?????? -?? and Latent heat of steam = ?? . ???? × ????
?? ?????? -?? ) 
A. 3043 J 
B. 3024 J 
C. 3003 J 
D. 3022 J 
Ans: A 
Solution: 
 
??? 1
= m × S
1
× ?T = 10
-3
× 2100× 10 = 21 J
??? 2
= m × L
f
= 10
-3
× 3.35 × 10
5
= 335 J
??? 3
= m × S
w
× ?T = 10
-3
× 4180× 100 = 418 J
?Q
4
= m × L
v
= 10
-3
× 2.25 × 10
6
= 2250 J
?Q
5
= m × S
v
× ?T = 10
-3
× 1920 × 10 = 19.2 J
?Q
net 
= 3043.2 J
 
 
Q3: A gun fires a lead bullet of temperature 300 K into a wooden block. The bullet 
having melting temperature of 600 K penetrates into the block and melts down. If the 
total heat required for the process is 625 J , then the mass of the bullet is ____ grams. 
(Latent heat of fusion of lead = ?? . ?? × ????
?? ?????? -?? and specific heat capacity of lead =
?????? ?????? -?? ?? -?? ) 
A. 10 
B. 20 
C. 5 
D. 15 
Ans: A 
Solution: 
 
Q4: Three conductors of same length having thermal conductivity ?? ?? , ?? ?? and ?? ?? are 
connected as shown in figure. 
 
Area of cross sections of ?? st 
 and ?? nd 
 conductor are same and for ?? rd 
 conductor it is 
double of the ?? st 
 conductor. The temperatures are given in the figure. In steady state 
condition, the value of ?? is ____  
°
?? . 
(Given : ?? ?? = ???? ????
-?? ?? -?? ?? -?? , ?? ?? = ?????? ????
-?? ?? -?? ?? -?? , ?? ?? = ?????? ????
-?? ?? -?? ?? -?? ) 
Ans: 40 
Solution: 
 
R
1
=
2L
K
1
A
R
2
=
2L
K
2
A
R
3
=
L
K
3
A
?? - 100
R
1
R
2
R
1
+ R
2
+
?? - 0
R
3
= 0
?? = 40
 
Q5: Two spherical bodies of same materials having radii 0.2 m and 0.8 m are placed in 
same atmosphere. The temperature of the smaller body is 800 K and temperature of 
the bigger body is 400 K . If the energy radiated from the smaller body is E , the energy 
radiated from the bigger body is (assume, effect of the surrounding temperature to be 
negligible) 
A. 16 E 
B. ?? 
C. 64 E 
D. 256 E 
Ans: B 
Solution:  
d?? dt
= ?? eAT
4
? P ? AT
4
P
smaller 
P
larger 
=
(0.2)
2
× 800
4
(0.8)
2
× 400
4
1
16
× 16 = 1
 ? P
larger 
= P
smaller 
 
Q6: A cup of coffee cools from ????
°
?? to ????
°
?? in t minutes when the room temperature 
is ????
°
?? . The time taken by the similar cup of coffee to cool from ????
°
?? to ????
°
?? at the 
same room temperature is : 
A. 
13
10
t 
B. 
10
13
t 
C. 
5
13
t 
D. 
13
5
t 
Ans: D 
Solution: 
By using average form of Newton's law of cooling 
90 - 80
t
= k (
90 + 80
2
- 20)
80 - 60
t
'
= k (
80 + 60
2
- 20)
 
(i)/(ii) 
10 × ?? '
?? × 20
=
65
50
?? '
=
65
50
× 2?? =
65
25
?? =
13
5
?? 
Q7: The temperature of a body in air falls from ????
°
?? to ????
°
?? in 4 minutes. The 
temperature of the air is ????
°
?? . The temperature of the body in the next 4 minutes will 
be: 
A. 
14
3
 
°
C 
B. 
42
3
 
°
C