Thermodynamics: JEE Mains Previous Year Questions (2021-2024) | Physics for JEE Main & Advanced PDF Download

 Page 1


 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The pressure and volume of an ideal gas are related as PV
3/2
= K (Constant). The work 
done by gas when the gas is taken from state ?? ?? 1
,?? 1
,?? 1
  to state B P
2
, V
2
, T
2
  is : 
[We modified question statement, In official NTA paper question was incomplete] 
(1) 2 P
1
 V
1
-P
2
 V
2
  
(2) 2 P
2
 V
2
-P
1
 V
1
  
(3) 2  P
1
 V
1
- P
2
 V
2
  
(4) 2 ?? 2
 ?? 2
-?? 1
 ?? 1
  
 
Q2 - 2024 (01 Feb Shift 2) 
A diatomic gas (?=1.4) does 200 J of work when it is expanded isobarically. The heat 
given to the gas in the process is: 
(1) 850 J 
(2) 800 J 
(3) 600 J 
(4) 700 J 
 
Q3 - 2024 (27 Jan Shift 1) 
0.08 kg air is heated at constant volume through 5
°
C. The specific heat of air at constant 
volume is 0.17kcal/kg
°
C and J =4.18 joule /cal. The change in its internal energy is 
approximately. 
(1) 318 J 
(2) 298 J 
(3) 284 J 
(4) 142 J 
 
Q4 - 2024 (27 Jan Shift 2) 
During an adiabatic process, the pressure of a gas is found to be proportional to the cube 
of its absolute temperature. The ratio of 
?? ?? ?? ?? Cp/Cv for the gas is : 
(1) 
5
3
 
(2) 
3
2
 
Page 2


 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The pressure and volume of an ideal gas are related as PV
3/2
= K (Constant). The work 
done by gas when the gas is taken from state ?? ?? 1
,?? 1
,?? 1
  to state B P
2
, V
2
, T
2
  is : 
[We modified question statement, In official NTA paper question was incomplete] 
(1) 2 P
1
 V
1
-P
2
 V
2
  
(2) 2 P
2
 V
2
-P
1
 V
1
  
(3) 2  P
1
 V
1
- P
2
 V
2
  
(4) 2 ?? 2
 ?? 2
-?? 1
 ?? 1
  
 
Q2 - 2024 (01 Feb Shift 2) 
A diatomic gas (?=1.4) does 200 J of work when it is expanded isobarically. The heat 
given to the gas in the process is: 
(1) 850 J 
(2) 800 J 
(3) 600 J 
(4) 700 J 
 
Q3 - 2024 (27 Jan Shift 1) 
0.08 kg air is heated at constant volume through 5
°
C. The specific heat of air at constant 
volume is 0.17kcal/kg
°
C and J =4.18 joule /cal. The change in its internal energy is 
approximately. 
(1) 318 J 
(2) 298 J 
(3) 284 J 
(4) 142 J 
 
Q4 - 2024 (27 Jan Shift 2) 
During an adiabatic process, the pressure of a gas is found to be proportional to the cube 
of its absolute temperature. The ratio of 
?? ?? ?? ?? Cp/Cv for the gas is : 
(1) 
5
3
 
(2) 
3
2
 
(3) 
7
5
 
(4) 
9
7
 
 
Q5 - 2024 (29 Jan Shift 1) 
A thermodynamic system is taken from an original state A to an intermediate state B by a 
linear process as shown in the figure. It's volume is then reduced to the original value 
from B to C by an isobaric process. The total work done by the gas from ?? to ?? and ?? to ?? 
would be : 
 
[We changed options. In official NTA paper no option was correct.] 
(1) 33800 J 
(2) 2200 J 
(3) 600 J 
(4) 800 J 
 
Q6 - 2024 (30 Jan Shift 2) 
Choose the correct statement for processes A\& B shown in figure. 
Page 3


 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The pressure and volume of an ideal gas are related as PV
3/2
= K (Constant). The work 
done by gas when the gas is taken from state ?? ?? 1
,?? 1
,?? 1
  to state B P
2
, V
2
, T
2
  is : 
[We modified question statement, In official NTA paper question was incomplete] 
(1) 2 P
1
 V
1
-P
2
 V
2
  
(2) 2 P
2
 V
2
-P
1
 V
1
  
(3) 2  P
1
 V
1
- P
2
 V
2
  
(4) 2 ?? 2
 ?? 2
-?? 1
 ?? 1
  
 
Q2 - 2024 (01 Feb Shift 2) 
A diatomic gas (?=1.4) does 200 J of work when it is expanded isobarically. The heat 
given to the gas in the process is: 
(1) 850 J 
(2) 800 J 
(3) 600 J 
(4) 700 J 
 
Q3 - 2024 (27 Jan Shift 1) 
0.08 kg air is heated at constant volume through 5
°
C. The specific heat of air at constant 
volume is 0.17kcal/kg
°
C and J =4.18 joule /cal. The change in its internal energy is 
approximately. 
(1) 318 J 
(2) 298 J 
(3) 284 J 
(4) 142 J 
 
Q4 - 2024 (27 Jan Shift 2) 
During an adiabatic process, the pressure of a gas is found to be proportional to the cube 
of its absolute temperature. The ratio of 
?? ?? ?? ?? Cp/Cv for the gas is : 
(1) 
5
3
 
(2) 
3
2
 
(3) 
7
5
 
(4) 
9
7
 
 
Q5 - 2024 (29 Jan Shift 1) 
A thermodynamic system is taken from an original state A to an intermediate state B by a 
linear process as shown in the figure. It's volume is then reduced to the original value 
from B to C by an isobaric process. The total work done by the gas from ?? to ?? and ?? to ?? 
would be : 
 
[We changed options. In official NTA paper no option was correct.] 
(1) 33800 J 
(2) 2200 J 
(3) 600 J 
(4) 800 J 
 
Q6 - 2024 (30 Jan Shift 2) 
Choose the correct statement for processes A\& B shown in figure. 
 
(1) PV
?? =k for process B and PV = k for process A. 
(2) PV=k for process B and A. 
(3) 
?? ?? P
?? -1
= ?? for process ?? and ?? ?? = ?? for process ?? . 
(4) None of these 
 
Q7 - 2024 (31 Jan Shift 1) 
The given figure represents two isobaric processes for the same mass of an ideal gas, 
then 
Page 4


 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The pressure and volume of an ideal gas are related as PV
3/2
= K (Constant). The work 
done by gas when the gas is taken from state ?? ?? 1
,?? 1
,?? 1
  to state B P
2
, V
2
, T
2
  is : 
[We modified question statement, In official NTA paper question was incomplete] 
(1) 2 P
1
 V
1
-P
2
 V
2
  
(2) 2 P
2
 V
2
-P
1
 V
1
  
(3) 2  P
1
 V
1
- P
2
 V
2
  
(4) 2 ?? 2
 ?? 2
-?? 1
 ?? 1
  
 
Q2 - 2024 (01 Feb Shift 2) 
A diatomic gas (?=1.4) does 200 J of work when it is expanded isobarically. The heat 
given to the gas in the process is: 
(1) 850 J 
(2) 800 J 
(3) 600 J 
(4) 700 J 
 
Q3 - 2024 (27 Jan Shift 1) 
0.08 kg air is heated at constant volume through 5
°
C. The specific heat of air at constant 
volume is 0.17kcal/kg
°
C and J =4.18 joule /cal. The change in its internal energy is 
approximately. 
(1) 318 J 
(2) 298 J 
(3) 284 J 
(4) 142 J 
 
Q4 - 2024 (27 Jan Shift 2) 
During an adiabatic process, the pressure of a gas is found to be proportional to the cube 
of its absolute temperature. The ratio of 
?? ?? ?? ?? Cp/Cv for the gas is : 
(1) 
5
3
 
(2) 
3
2
 
(3) 
7
5
 
(4) 
9
7
 
 
Q5 - 2024 (29 Jan Shift 1) 
A thermodynamic system is taken from an original state A to an intermediate state B by a 
linear process as shown in the figure. It's volume is then reduced to the original value 
from B to C by an isobaric process. The total work done by the gas from ?? to ?? and ?? to ?? 
would be : 
 
[We changed options. In official NTA paper no option was correct.] 
(1) 33800 J 
(2) 2200 J 
(3) 600 J 
(4) 800 J 
 
Q6 - 2024 (30 Jan Shift 2) 
Choose the correct statement for processes A\& B shown in figure. 
 
(1) PV
?? =k for process B and PV = k for process A. 
(2) PV=k for process B and A. 
(3) 
?? ?? P
?? -1
= ?? for process ?? and ?? ?? = ?? for process ?? . 
(4) None of these 
 
Q7 - 2024 (31 Jan Shift 1) 
The given figure represents two isobaric processes for the same mass of an ideal gas, 
then 
 
(1) ?? 2
= ?? 1
 
(2) ?? 2
> ?? 1
 
(3) ?? 1
= ?? 2
 
(4) ?? 1
> ?? 2
 
 
Answer Key 
Q1 (1) 
Q2 (4) 
Q5 (4) 
Q6 (1) 
Q3 (3) 
Q7 (4) 
 
 
Solutions 
 
Q1 
For PV
x
= constant 
If work done by gas is asked then 
W =
nR?T
1-x
 
Here x =
3
2
 
Page 5


 
2024 
 
Q1 - 2024 (01 Feb Shift 1) 
The pressure and volume of an ideal gas are related as PV
3/2
= K (Constant). The work 
done by gas when the gas is taken from state ?? ?? 1
,?? 1
,?? 1
  to state B P
2
, V
2
, T
2
  is : 
[We modified question statement, In official NTA paper question was incomplete] 
(1) 2 P
1
 V
1
-P
2
 V
2
  
(2) 2 P
2
 V
2
-P
1
 V
1
  
(3) 2  P
1
 V
1
- P
2
 V
2
  
(4) 2 ?? 2
 ?? 2
-?? 1
 ?? 1
  
 
Q2 - 2024 (01 Feb Shift 2) 
A diatomic gas (?=1.4) does 200 J of work when it is expanded isobarically. The heat 
given to the gas in the process is: 
(1) 850 J 
(2) 800 J 
(3) 600 J 
(4) 700 J 
 
Q3 - 2024 (27 Jan Shift 1) 
0.08 kg air is heated at constant volume through 5
°
C. The specific heat of air at constant 
volume is 0.17kcal/kg
°
C and J =4.18 joule /cal. The change in its internal energy is 
approximately. 
(1) 318 J 
(2) 298 J 
(3) 284 J 
(4) 142 J 
 
Q4 - 2024 (27 Jan Shift 2) 
During an adiabatic process, the pressure of a gas is found to be proportional to the cube 
of its absolute temperature. The ratio of 
?? ?? ?? ?? Cp/Cv for the gas is : 
(1) 
5
3
 
(2) 
3
2
 
(3) 
7
5
 
(4) 
9
7
 
 
Q5 - 2024 (29 Jan Shift 1) 
A thermodynamic system is taken from an original state A to an intermediate state B by a 
linear process as shown in the figure. It's volume is then reduced to the original value 
from B to C by an isobaric process. The total work done by the gas from ?? to ?? and ?? to ?? 
would be : 
 
[We changed options. In official NTA paper no option was correct.] 
(1) 33800 J 
(2) 2200 J 
(3) 600 J 
(4) 800 J 
 
Q6 - 2024 (30 Jan Shift 2) 
Choose the correct statement for processes A\& B shown in figure. 
 
(1) PV
?? =k for process B and PV = k for process A. 
(2) PV=k for process B and A. 
(3) 
?? ?? P
?? -1
= ?? for process ?? and ?? ?? = ?? for process ?? . 
(4) None of these 
 
Q7 - 2024 (31 Jan Shift 1) 
The given figure represents two isobaric processes for the same mass of an ideal gas, 
then 
 
(1) ?? 2
= ?? 1
 
(2) ?? 2
> ?? 1
 
(3) ?? 1
= ?? 2
 
(4) ?? 1
> ?? 2
 
 
Answer Key 
Q1 (1) 
Q2 (4) 
Q5 (4) 
Q6 (1) 
Q3 (3) 
Q7 (4) 
 
 
Solutions 
 
Q1 
For PV
x
= constant 
If work done by gas is asked then 
W =
nR?T
1-x
 
Here x =
3
2
 
? W=
P
2
 V
2
-P
1
 V
1
-
1
2
 
= 2 P
1
 V
1
-P
2
 V
2
  
Option (1) is correct 
If work done by external is asked then W = -2 P
1
 V
1
-P
2
 V
2
 …… Option (2) is correct 
 
Q2 
?? =1+
2
f
=1.4 ?
2
f
=0.4 
?f =5 
W =n?? ?T = 200 J 
Q = 
f+2
2
 nR?T 
=
7
2
×200 = 700 J 
 
Q3 
Q = ?U as work done is zero [constant volume] 
?U =ms?T 
= 0.08×(170×4.18)×5 
? 284 J 
 
Q4 
P ?T
3
?PT
-3
= constan 
PV
?? = const 
P 
nRT
P
 
?? = const 
P
1-?? T
?? = const 
PT
?? 1-?? = const 
?? 1-?? = -3 
?? = -3+3?? 
3=2?? 
?? =
3
2
 
 
Q5