JEE-MAIN SERIES
Physics

Thermodynamics

174 previous year questions.

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Chapter Questions
174 MCQs

01
PYQ 2013
medium
physics ID: jee-main
An ideal gas at atmospheric pressure is adiabatically compressed so that its density becomes times of its initial value. If the final pressure of gas is atmospheres, the value of ? ?of the gas is :
1
2
3
4
02
PYQ 2013
easy
physics ID: jee-main
The shown p- V diagram represents the thermodynamic cycle of an engine, operating with an ideal monoatomic gas. The amount of heat, extracted from the source in a single cycle is
1
2
3
4
03
PYQ 2014
easy
physics ID: jee-main
An ideal monoatomic gas is confined in a cylinder by a spring loaded piston of cros section . Initially the gas is at 300K and occupies a volume of and the spring is in its relaxed state as shown in figure. The gas is heated by a small heater until the piston moves out slowly by . The force constant of the spring is and the atmospheric pressure is . The cylinder and the piston are thermally insulated. The piston and the spring are massless and there is no friction between the piston and the cylinder. The final temperature of the gas will be : (Neglect the heat loss through the lead wires of the heater. The heat capacity of the heater coil is also negligible)
1
300 K
2
800 K
3
500 K
4
1000 K
04
PYQ 2014
medium
physics ID: jee-main
During an adiabatic compression, of work is done on moles of a diatomic ideal gas to reduce its volume by . The change in its temperature is nearly :
1
40 K
2
33 K
3
20 K
4
14 K
05
PYQ 2014
hard
physics ID: jee-main
A gas is compressed from a volume of to a volume of at a constant pressure of . Then it is heated at constant volume by supplying of energy. As a result, the internal energy of the gas :
1
Increases by 250 J
2
Decreases by 250 J
3
Increases by 50 J
4
Decreases by 50 J
06
PYQ 2015
medium
physics ID: jee-main
Consider a spherical shell of radius at temperature . The black body radiation inside it can be considered as an ideal gas of photons with internal energy per unit volume and pressure If the shell now undergoes an adiabatic expansion, the relation between and is
1
2
3
4
07
PYQ 2015
medium
physics ID: jee-main
Consider an ideal gas confined in an isolated closed chamber. As the gas undergoes an adiabatic expansion, the average time of collision between molecules increases as , where is the volume of the gas. The value of is
1
2
3
4
08
PYQ 2015
medium
physics ID: jee-main
A solid body of constant heat capacity is being heated by keeping it in contact with reservoirs in two ways (i) Sequentially keeping in contact with reservoirs such that each reservoir supplies same amount of heat. (ii) Sequentially keeping in contact with reservoirs such that each reservoir supplies same amount of heat. In both the cases, body is brought from initial temperature to final temperature . Entropy change of the body in the two cases respectively, is
1
In (2), In 2
2
In 2, 2 ln 2
3
2 ln 2, 8 In 2
4
In 2,4 In 2
09
PYQ 2016
easy
physics ID: jee-main
A Carnot freezer takes heat from water at inside it and rejects it to the room at a temperature of . The latent heat of ice is . If of water at is converted into ice at by the freezer, then the energy consumed by the freezer is close to :
1
2
3
4
10
PYQ 2016
medium
physics ID: jee-main
An ideal gas undergoes a quasi static, reversible process in which its molar heat capacity Cremains constant. If during this process the relation of pressure and volume is given by constant, then is given by (Here and are molar specific heat at constant pressure and constant volume, respectively) :
1
2
3
4
11
PYQ 2016
medium
physics ID: jee-main
moles of an ideal gas undergoes a process as shown in the figure. The maximum temperature of the gas during the process will be :
1
2
3
4
12
PYQ 2017
medium
physics ID: jee-main
and are specific heats at constant pressure and constant volume respectively. It is observed that = a for hydrogen gas = b for nitrogen gas The correct relation between and is :
1
2
3
4
13
PYQ 2017
medium
physics ID: jee-main
An engine operates by taking moles of an ideal gas through the cycle shown in figure. The thermal efficiency of the engine is : (Take where is gas constant)
1
0.24
2
0.15
3
0.32
4
0.08
14
PYQ 2019
medium
physics ID: jee-main
A gas can be taken from to via two different processes and . When path is used of heat flows into the system and of work is done by the system. If path is used work done by the system is . The heat Flow into the system in path is :
1
80 J
2
20 J
3
100 J
4
40 J
15
PYQ 2019
medium
physics ID: jee-main
A thermally insulated vessel contains of water at . Then the air from the vessel is pumped out adiabatically. A fraction of water turns into ice and the rest evaporates at itself. The mass of evaporated water will be closest to : (Latent heat of vaporization of water and Latent heat of Fusion of water = )
1
130 g
2
35 g
3
20 g
4
150 g
16
PYQ 2019
medium
physics ID: jee-main
For the given cyclic process as shown for a gas, the work done is :
1
1 J
2
5 J
3
10 J
4
30 J
17
PYQ 2019
medium
physics ID: jee-main
Half mole of an ideal monoatomic gas is heated at constant pressure of 1 atm from to . Work done by gas is close to : ( Gas constant R = )
1
73 J
2
291 J
3
581 J
4
146 J
18
PYQ 2019
medium
physics ID: jee-main
A sample of an ideal gas is taken through the cyclic process abca as shown in the figure. The change in the internal energy of the gas along the path ca is . The gas absorbs of heat along the path ab and along the path . The work done by the gas along the path is :
1
100 J
2
120 J
3
140 J
4
130 J
19
PYQ 2019
medium
physics ID: jee-main
A rigid diatomic ideal gas undergoes an adiabatic process at room temperature,. The relation between temperature and volume of this process is = constant, then is :
1
2
3
4
20
PYQ 2020
medium
physics ID: jee-main
A thermodynamic cycle is shown on a diagram. The diagram that best describes this cycle is : (Diagrams are schematic and not to scale)
1
2
3
4
21
PYQ 2021
medium
physics ID: jee-main
A refrigerator consumes an average 35 W power to operate between temperature -10 C to 25 C. If there is no loss of energy then how much average heat per second does it transfer ?
1
35 J/s
2
263 J/s
3
298 J/s
4
350 J/s
22
PYQ 2021
medium
physics ID: jee-main
A diatomic gas, having and , is heated at constant pressure. The ratio :
1
5 : 7 : 2
2
3 : 7 : 2
3
3 : 5 : 2
4
5 : 7 : 3
23
PYQ 2021
medium
physics ID: jee-main
An ideal gas in a cylinder is separated by a piston in such a way that the entropy of one part is and that of the other part is . Given that . If the piston is removed then the total entropy of the system will be:
1

2

3

4
24
PYQ 2021
medium
physics ID: jee-main
For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where is the ratio of specific heats):
1

2

3

4
25
PYQ 2021
medium
physics ID: jee-main
A heat engine operates between a cold reservoir at temperature T = 400 K and a hot reservoir at temperature T . It takes 300 J of heat from the hot reservoir and delivers 240 J of heat to the cold reservoir in a cycle. The minimum temperature of the hot reservoir has to be _________ K.
26
PYQ 2021
medium
physics ID: jee-main
A reversible engine has an efficiency of . If the temperature of the sink is reduced by , its efficiency becomes double. Calculate the temperature of the sink :
1

2

3

4
27
PYQ 2021
medium
physics ID: jee-main

In the reported figure, there is a cyclic process ABCDA on a sample of 1 mol of a diatomic gas. The temperature of the gas during the process A B and C D are and ( ) respectively. Choose the correct option out of the following for work done if processes BC and DA are adiabatic.

1

2

3

4

28
PYQ 2021
medium
physics ID: jee-main
An ideal gas is expanding such that . The coefficient of volume expansion of the gas is :
1

2

3

4

29
PYQ 2021
medium
physics ID: jee-main
A small object is placed at the center of a large evacuated hollow spherical container. Assume that the container is maintained at . At time , the temperature of the object is . The temperature of the object becomes at and at .Assume the object and the container to be ideal black bodies. The heat capacity of the object does not depend on temperature. The ratio is______
30
PYQ 2021
medium
physics ID: jee-main
For an ideal gas the instantaneous change in pressure 'p' with volume 'v' is given by the equation . If at is the given boundary condition, then the maximum temperature one mole of gas can attain is : (Here R is the gas constant)
1

2

3

4
infinity
31
PYQ 2021
medium
physics ID: jee-main
The height of victoria falls is 63 m. What is the difference in temperature of water at the top and at the bottom of fall?
[Given 1 cal = 4.2 J and specific heat of water = 1 cal g C ]

1
0.014 C
2
0.147 C
3
1.476 C
4
14.76 C
32
PYQ 2021
medium
physics ID: jee-main
A sample of gas with is taken through an adiabatic process in which the volume is compressed from 1200 to 300 . If the initial pressure is 200 kPa. The absolute value of the workdone by the gas in the process = ________ J.
33
PYQ 2021
medium
physics ID: jee-main

Thermodynamic process is shown below on a P-V diagram for one mole of an ideal gas. If then the ratio of temperature is: The process is = constant.

1

2

3

4
2
34
PYQ 2021
medium
physics ID: jee-main
A reversible heat engine converts one-fourth of the heat input into work. When the temperature of the sink is reduced by 52 K, its efficiency is doubled. The temperature in Kelvin of the source will be ________ .
35
PYQ 2021
medium
physics ID: jee-main
In a thermodynamical process, . The work done when the temperature changes from 100°C to 300°C will be ________ nR.
36
PYQ 2021
medium
physics ID: jee-main
For a gas in a state P and in a state Q. and are the temperatures in two different states P and Q respectively. Then
1

2

3

4
37
PYQ 2021
medium
physics ID: jee-main
A monoatomic ideal gas, initially at temperature , is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature by releasing the piston suddenly. If and are the lengths of the gas column, before and after the expansion respectively, then the value of will be :
1

2

3

4
38
PYQ 2021
medium
physics ID: jee-main

The P-V diagram of a diatomic ideal gas system going under cyclic process as shown in figure. The work done during an adiabatic process CD is (use γ = 1.4) :

1
400 J
2
-500 J
3
200 J
4
-400 J
39
PYQ 2021
medium
physics ID: jee-main
An electric appliance supplies 6000 J/min heat to the system. If the system delivers a power of 90 W. How long it would take to increase the internal energy by J ?
1
s
2
s
3
s
4
s
40
PYQ 2021
medium
physics ID: jee-main

A perfect gas undergoes a cyclic process ABCA. A→B: Isothermal expansion ( ). B→C: Isobaric compression to . C→A: Isochoric change to . Total work done is :

1
0
2
nRTln 2
3
nRT (ln 2 + 1/2)
4
nRT (ln 2 - 1/2)
41
PYQ 2021
medium
physics ID: jee-main
Match List I with List II.
List I: (a) Isothermal (b) Isochoric (c) Adiabatic (d) Isobaric.
List II: (i) Pressure constant (ii) Temperature constant (iii) Volume constant (iv) Heat content constant.
1
(a)→(i), (b)→(iii), (c)→(ii), (d)→(iv)
2
(a)→(iii), (b)→(ii), (c)→(i), (d)→(iv)
3
(a)→(ii), (b)→(iv), (c)→(iii), (d)→(i)
4
(a)→(ii), (b)→(iii), (c)→(iv), (d)→(i)
42
PYQ 2021
medium
physics ID: jee-main
One mole of an ideal gas is taken through an adiabatic process where the temperature rises from to . If the ideal gas is composed of polyatomic molecule that has 4 vibrational modes, which of the following is true?
[R = 8.314 J mol K ]

1
work done by the gas is close to 582 J
2
work done on the gas is close to 582 J
3
work done by the gas is close to 332 J
4
work done on the gas is close to 332 J
43
PYQ 2021
medium
physics ID: jee-main
Two Carnot engines A and B operate in series such that engine A absorbs heat at and rejects heat to a sink at temperature T. Engine B absorbs half of the heat rejected by Engine A and rejects heat to the sink at . When workdone in both the cases is equal, the value of T is :
1

2

3

4

44
PYQ 2021
medium
physics ID: jee-main

If one mole of an ideal gas at is allowed to expand reversibly and isothermally (A to B) its pressure is reduced to one-half of the original pressure. This is followed by a constant volume cooling till its pressure is reduced to one-fourth of the initial value (B → C). Then it is restored to its initial state by a reversible adiabatic compression (C to A). The net work done by the gas is equal to :

1
RT ln 2 -
2

3
RT ln 2
4
0
45
PYQ 2022
medium
physics ID: jee-main

Given below are two statements
Statement-I: When μ amount of an ideal gas undergoes adiabatic change from state (P1, V1, T1) to state (P2, V2, T2), then work done is

,where
and R = universal gas constant.
Statement-II: In the above case, when work is done on the gas, the temperature of the gas would rise.
Choose the correct answer from the options given below.

1
Both statement-I and statement-II are true
2
Both statement-I and statement-II are false
3
Statement-I is true but statement-II is false
4
Statement-I is false but statement-II is true
46
PYQ 2022
easy
physics ID: jee-main
An ice cube of dimensions 60 cm × 50 cm × 20 cm is placed in an insulation box of wall thickness 1 cm. The box keeping the ice cube at 0°C of temperature is brought to a room of temperature 40°C. The rate of melting of ice is approximately. (Latent heat of fusion of ice is and thermal conducting of insulation wall is °
1
2
3
4
47
PYQ 2022
medium
physics ID: jee-main
Consider two containers A and B containing monoatomic gases at the same Pressure (P), Volume (V) and Temperature (T). The gas in A is compressed isothermally to of its original volume while the gas in B is com pressed adiabatically to of its original volume. The ratio of final pressure of gas in B to that of gas in A is
1

2

8

3

4

4

48
PYQ 2022
medium
physics ID: jee-main
0.056 kg of Nitrogen is enclosed in a vessel at a temperature of 127°C. The amount of heat required to double the speed of its molecules is ___ k cal.(Take R = 2 cal mol–1 K–1)
49
PYQ 2022
medium
physics ID: jee-main
A heat engine operates with the cold reservoir at temperature 324 K. The minimum temperature of the hot reservoir, if the heat engine takes 300 J heat from the hot reservoir and delivers 180 J heat to the cold reservoir per cycle, is _____ K.
50
PYQ 2022
medium
physics ID: jee-main

A sample of an ideal gas is taken through the cyclic process ABCA as shown in figure. It absorbs, 40 J of heat during the part AB, no heat during BC and rejects 60 J of heat during CA. A work of 50 J is done on the gas during the part BC. The internal energy of the gas at A is 1560 J. The work done by the gas during the part CA is:

Fig.
1
20 J
2
30 J
3
–30 J
4
–60 J
51
PYQ 2022
medium
physics ID: jee-main

The total internal energy of two mole monoatomic ideal gas at temperature T=300 K will be _____J.
(Given R = 8.31 J/mol.K)

52
PYQ 2022
medium
physics ID: jee-main
Starting with the same initial conditions, an ideal gas expands from volume V1 to V2 in three different ways. The work done by the gas is W1 if the process is purely isothermal, W2, if the process is purely adiabatic and W3 if the process is purely isobaric. Then, choose the correct option.
1
W1 < W2 < W3
2
W2 < W3 < W1
3
W3 < W1 < W2
4
W2 < W1 < W3
53
PYQ 2022
easy
physics ID: jee-main
A vessel contains 16 g of hydrogen and 128 g of oxygen at standard temperature and pressure. The volume of the vessel in cm3 is:
1
72 \times 105
2
32 \times 105
3
27 \times 104
4
54 \times 104
54
PYQ 2022
medium
physics ID: jee-main
At a certain temperature, the degrees of freedom per molecule for gas is 8. The gas performs 150 J of work when it expands under constant pressure. The amount of heat absorbed by the gas will be ______ J.
55
PYQ 2022
medium
physics ID: jee-main
The pressure P1 and density d1 of diatomic gas changes suddenly to and d2 respectively during an adiabatic process. The temperature of the gas increases and becomes _____ times of its initial temperature.
(Given )
56
PYQ 2022
medium
physics ID: jee-main

In a carnot engine, the temperature of reservoir is 527°C and that of sink is 200 K. If the work done by the engine when it transfers heat from reservoir to sink is 12000 kJ, the quantity of heat absorbed by the engine from reservoir is _____ J.

57
PYQ 2023
easy
physics ID: jee-main
The graph between two temperature scales and is shown in the figure Between upper fixed point and lower fixed point there are 150 equal divisions of scale and 100 divisions on scale : The relationship for conversion between the two scales is given by:-
1
2
3
4
58
PYQ 2023
medium
physics ID: jee-main
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason
Assertion A: Efficiency of a reversible heat engine will be highest at temperature of cold reservoir
Reason R: The efficiency of Carnot's engine depends not only on temperature of cold reservoir but it depends on the temperature of hot reservoir too and is given as
In the light of the above statements, choose the correct answer from the options given below
1
is true but is false
2
Both and are true and is the correct explanation of
3
Both and are true but is NOT the correct explanation of
4
A is false but is true
59
PYQ 2023
easy
physics ID: jee-main
Let is the efficiency of an engine at and while is the efficiency at and The ratio will be :
1
2
3
4
60
PYQ 2023
easy
physics ID: jee-main
A Carnot engine with efficiency takes heat from a source at In order to increase the efficiency to , keeping the temperature of sink same, the new temperature of the source will be :
1
2
3
4
61
PYQ 2023
easy
physics ID: jee-main
In which of the following process, the internal energy of gas remains constant
1
Isothermal
2
Isochoric
3
Isobaric
4
Adiabatic
62
PYQ 2023
medium
physics ID: jee-main

Ratio of molar heat capacity at constant pressure and at constant volume for monoatomic and diatomic gas is?

1

25 : 21

2

21 : 25

3

16 : 25

4

25 : 16

63
PYQ 2023
easy
physics ID: jee-main
A Carnot engine working between 27°C and 127°C performs 2 kJ of work. The amount of heat rejected is equal to:
1
4 kJ
2
8 kJ
3
6 kJ
4
12 kJ
64
PYQ 2023
medium
physics ID: jee-main
Pressure for polytropic process P varies with volume V as P=av-3, find out the bulk modulus.
1
3V
2
3P
3
P
4
V
65
PYQ 2023
easy
physics ID: jee-main
In a thermodynamic process work done by gas is 1000 J & heat supplied is 200 J. Find change in internal energy of gas?
1
800 J
2
-800 J
3
1200 J
4
-1200 J
66
PYQ 2023
hard
physics ID: jee-main
of a liquid is converted to vapour at pressure If of the heat supplied is used for increasing the volume by during this phase change, then the increase in internal energy in the process will be:
1
2
3
4
67
PYQ 2023
medium
physics ID: jee-main
In an Isothermal change, the change in pressure and volume of a gas can be represented for three different temperature as :
1

2

3

4

68
PYQ 2023
medium
physics ID: jee-main
A source supplies heat to a system at the rate of 1000 W. If the system performs work at a rate of 200 W. The rate at which internal energy of the system increase is
1
500 W
2
600 W
3
800 W
4
1200 W
69
PYQ 2023
medium
physics ID: jee-main
The initial pressure and volume of an ideal gas are P0 and V0. The final pressure of the gas when the gas is suddenly compressed to volume will be(Given γ = ratio of specific heats at constant pressure and at constant volume)
1
2
3
4
70
PYQ 2023
medium
physics ID: jee-main
1 kg of water at 100°C is converted into steam at 100°C by boiling at atmospheric pressure. The volume of water changes from as a liquid to as steam. The change in internal energy of the system during the process will be:
1
+ 2476 kJ
2
-2426 kJ
3
-2090 kJ
4
+2090 kJ
71
PYQ 2023
medium
physics ID: jee-main
Given below are two statements:
Statement I: If heat is added to a system, its temperature must increase.
Statement II: If positive work is done by a system in a thermodynamic process, its volume must increase.
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
Both Statement I and Statement II are false
3
Statement I is true but Statement II is false
4
Statement I is false but Statement II is true
72
PYQ 2023
hard
physics ID: jee-main
Heat energy of 184 kJ is given to ice of mass at −12°C. Specific heat of ice is and latent heat of ice in
A. Final temperature of system will be 0°C.
B. Final temperature of the system will be greater than 0°C.
C. The final system will have a mixture of ice and water in the ratio of 5:1.
D. The final system will have a mixture of ice and water in the ratio of 1:5.
E. The final system will have water only.
Choose the correct answer from the options given below:
1
A and D Only
2
A and E Only
3
A and C Only
4
B and D Only
73
PYQ 2023
hard
physics ID: jee-main
A thermodynamic system is taken through cyclic process. The total work done in the process is:
A thermodynamic system is taken through cyclic process
1
Zero
2
200J
3
100J
4
300J
74
PYQ 2024
easy
physics ID: jee-main
0.08 kg of air is heated at constant volume through 5°C. The specific heat of air at constant volume is 0.17 kcal/kg°C and joule/cal. The change in its internal energy is approximately:
1
318 J
2
298 J
3
284 J
4
142 J
75
PYQ 2024
easy
physics ID: jee-main
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio of for the gas is :
1
2
3
4
76
PYQ 2024
medium
physics ID: jee-main
Two thermodynamical processes are shown in the figure. The molar heat capacity for process and are and . The molar heat capacity at constant pressure and constant volume are represented by and , respectively. Choose the correct statement.
Figure
1
2
3
4
77
PYQ 2024
medium
physics ID: jee-main
Two different adiabatic paths for the same gas intersect two isothermal curves as shown in the diagram. The relation between the ratio and the ratio is:
angle
1
2
3
4
78
PYQ 2024
hard
physics ID: jee-main
A diatomic gas ( ) does 100 J of work in an isobaric expansion. The heat given to the gas is:
1
350 J
2
490 J
3
150 J
4
250 J
79
PYQ 2024
medium
physics ID: jee-main
The heat absorbed by a system in going through the given cyclic process is :
Fig
1
61.6 J
2
431.2 J
3
616 J
4
19.6 J
80
PYQ 2024
medium
physics ID: jee-main
Match List I with List II
Choose the correct answer from the options given below :
1
A-I, B-III, C-II, D-IV
2
A-IV, B-III, C-II, D-I
3
A-III, B-I, C-II, D-IV
4
A-IV, B-II, C-III, D-I
81
PYQ 2024
medium
physics ID: jee-main
The specific heat at constant pressure of a real gas obeying equation is:
1
2
3
4
82
PYQ 2024
medium
physics ID: jee-main
A mixture of one mole of a monoatomic gas and one mole of a diatomic gas (rigid) are kept at room temperature ( ). The ratio of specific heat of gases at constant volume respectively is:
1
2
3
4
83
PYQ 2024
easy
physics ID: jee-main
A gas mixture consists of 8 moles of argon and 6 moles of oxygen at temperature T. Neglecting all vibrational modes, the total internal energy of the system is
1
29 RT
2
20 RT
3
27 RT
4
21 RT
84
PYQ 2024
medium
physics ID: jee-main

Given below are two statements:
Statement 1: If a capillary tube is immersed first in cold water and then in hot water, the height of capillary rise will be smaller in hot water.
Statement 2: If a capillary tube is immersed first in cold water and then in hot water, the height of capillary rise will be smaller in cold water.
In the light of the above statements, choose the most appropriate option 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
Both Statement I and Statement II are true
4
Statement I is false but Statement II is true
85
PYQ 2024
medium
physics ID: jee-main
A diatomic gas ( ) 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
86
PYQ 2024
medium
physics ID: jee-main
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 A to B and B to C would be :
Thermodynamic Graph
1
33800 J
2
2200 J
3
0 J
4
1200 J
87
PYQ 2024
medium
physics ID: jee-main
On Celsius scale, the temperature of a body increases by . The increase in temperature on Fahrenheit scale is:
1
2
3
4
88
PYQ 2024
medium
physics ID: jee-main
A sample of 1 mole gas at temperature T is adiabatically expanded to double its volume. If adiabatic constant for the gas is , then the work done by the gas in the process is:
1
2
3
4
89
PYQ 2024
medium
physics ID: jee-main
Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating element should be ………….. to …………. times of its initial length if the water is to be boiled in 15 minutes.
1
increased,
2
increased,
3
decreased,
4
decreased,
90
PYQ 2024
medium
physics ID: jee-main
A total of 48 J heat is given to one mole of helium kept in a cylinder. The temperature of helium increases by . The work done by the gas is: (Given, ).
1
72.9 J
2
24.9 J
3
48 J
4
23.1 J
91
PYQ 2024
medium
physics ID: jee-main
N moles of a polyatomic gas (f = 6) must be mixed with two moles of a monoatomic gas so that the mixture behaves as a diatomic gas. The value of N is :
1
6
2
3
3
4
4
2
92
PYQ 2024
medium
physics ID: jee-main
The given figure represents two isobaric processes for the same mass of an ideal gas, then
1
2
3
4
93
PYQ 2024
hard
physics ID: jee-main
A real gas within a closed chamber at undergoes the cyclic process as shown in the figure. The gas obeys equation for the path to . The net work done in the complete cycle is (assuming ):
Graph cycle
1
225 J
2
205 J
3
20 J
4
-20 J
94
PYQ 2024
medium
physics ID: jee-main
At room temperature the resistance of a heating element is . The temperature coefficient of the material is . The temperature of the element, when its resistance is , is _________ .
95
PYQ 2024
medium
physics ID: jee-main
P-T diagram of an ideal gas having three different densities (in three different cases) is shown in the figure. Which of the following is correct:
1
2
3
4
96
PYQ 2024
medium
physics ID: jee-main
A sample of gas at temperature is adiabatically expanded to double its volume. Adiabatic constant for the gas is . The work done by the gas in the process is ( mole):
1
2
3
4
97
PYQ 2024
hard
physics ID: jee-main
The Pressure (P) versus volume (V) of thermodynamic process shown in figure. The select the correct options (Take γ= 1.1)
 thermodynamic process shown in figure
1
For process A : PVY = constant, For process B : PVY = constant
2

For process A : PV = constant For process B : PV = constant

3
For process A : PV1.05 = constant For process B : PVY = constant
4
For process A : PV1.2 = constant For process B : PV = constant
98
PYQ 2024
medium
physics ID: jee-main
Choose the correct statement for processes A & B shown in figure.
1
for process B and for process A.
2
for process B and A.
3
for process B and for process A.
4
for process A and for process B.
99
PYQ 2024
medium
physics ID: jee-main
During an adiabatic process, if the pressure of a gas is found to be proportional to the cube of its absolute temperature, then the ratio of for the gas is :
1
2
3
4
100
PYQ 2024
easy
physics ID: jee-main
The pressure and volume of an ideal gas are related as (constant). The work done when the gas is taken from state A ( ) to state B ( ) is:
101
PYQ 2025
medium
physics ID: jee-main
A gas is kept in a container having walls which are thermally non-conducting. Initially the gas has a volume of 800 and temperature 27°C. The change in temperature when the gas is adiabatically compressed to 200 is: (Take = 1.5 : is the ratio of specific heats at constant pressure and at constant volume)
1
327 K
2
600 K
3
522 K
4
300 K
102
PYQ 2025
medium
physics ID: jee-main
Water falls from a height of 200 m. What is the increase in temperature when it touches the bottom? (Assume that all the heat goes into the same amount of mass which was falling).
1
2
3
4
103
PYQ 2025
medium
physics ID: jee-main
In an adiabatic process, which of the following statements is true?
1
The molar heat capacity is infinite
2
Work done by the gas equals the increase in internal energy
3
The molar heat capacity is zero
4
The internal energy of the gas decreases as the temperature increases
104
PYQ 2025
easy
physics ID: jee-main

Match List-I with List-II.

Choose the correct answer from the options given below :

1
(A)-(III), (B)-(II), (C)-(I), (D)-(IV)
2
(A)-(IV), (B)-(I), (C)-(III), (D)-(II)
3
(A)-(IV), (B)-(II), (C)-(III), (D)-(I)
4
(A)-(II), (B)-(IV), (C)-(I), (D)-(III)
105
PYQ 2025
medium
physics ID: jee-main

A piston of mass M is hung from a massless spring whose restoring force law goes as F = -kx, where k is the spring constant of appropriate dimension. The piston separates the vertical chamber into two parts, where the bottom part is filled with 'n' moles of an ideal gas. An external work is done on the gas isothermally (at a constant temperature T) with the help of a heating filament (with negligible volume) mounted in lower part of the chamber, so that the piston goes up from a height to , the total energy delivered by the filament is (Assume spring to be in its natural length before heating)

1
2
3
4

106
PYQ 2025
medium
physics ID: jee-main
A monoatomic gas having is stored in a thermally insulated container and the gas is suddenly compressed to of its initial volume. The ratio of final pressure and initial pressure is:
1
28
2
32
3
40
4
16
107
PYQ 2025
medium
physics ID: jee-main

An ideal gas has undergone through the cyclic process as shown in the figure. Work done by the gas in the entire cycle is _____ J. (Take )

108
PYQ 2025
medium
physics ID: jee-main
Water falls from a height of 200 m into a pool. Calculate the rise in temperature of the water assuming no heat dissipation from the water in the pool. (Take , specific heat of water = 4200 J/(kg K))
1
0.48 K
2
0.36 K
3
0.14 K
4
0.23 K
109
PYQ 2025
medium
physics ID: jee-main
During the melting of a slab of ice at 273 K at atmospheric pressure:
1
Internal energy of ice-water system remains unchanged.
2
Positive work is done by the ice-water system on the atmosphere.
3
Internal energy of the ice-water system decreases.
4
Positive work is done on the ice-water system by the atmosphere.
110
PYQ 2025
hard
physics ID: jee-main

Match the List-I with List-II.

Choose the correct answer from the options given below:

1
A-III, B-IV, C-I, D-II
2
A-III, B-II, C-IV, D-I
3
A-II, B-IV, C-I, D-III
4
A-IV, B-II, C-III, D-I
111
PYQ 2025
medium
physics ID: jee-main
The difference of temperature in a material can convert heat energy into electrical energy. To harvest the heat energy, the material should have:
1
low thermal conductivity and low electrical conductivity
2
high thermal conductivity and high electrical conductivity
3
low thermal conductivity and high electrical conductivity
4
high thermal conductivity and low electrical conductivity
112
PYQ 2025
medium
physics ID: jee-main
Pressure of an ideal gas, contained in a closed vessel, is increased by 0.4% when heated by . Its initial temperature must be :
1

2

3

4

113
PYQ 2025
medium
physics ID: jee-main
An ideal gas exists in a state with pressure , volume . It is isothermally expanded to 4 times of its initial volume , then isobarically compressed to its original volume. Finally the system is heated isochorically to bring it to its initial state. The amount of heat exchanged in this process is :
1

2

3

4

114
PYQ 2025
medium
physics ID: jee-main

The internal energy of air in sized room at 1 atmospheric pressure will be . (Consider air as a diatomic molecule)

115
PYQ 2025
medium
physics ID: jee-main
Given are statements for certain thermodynamic variables: \begin{itemize} \item[(A)] Internal energy, volume , and mass are extensive variables. \item[(B)] Pressure , temperature , and density are intensive variables. \item[(C)] Volume , temperature , and density are intensive variables. \item[(D)] Mass , temperature , and internal energy are extensive variables. \end{itemize} Choose the correct answer from the options given below:
1
(B) and (C) Only
2
(C) and (D) Only
3
(D) and (A) Only
4
(A) and (B) Only
116
PYQ 2025
medium
physics ID: jee-main
An ideal gas goes from an initial state to final state. During the process, the pressure of the gas increases linearly with temperature.
A. The work done by gas during the process is zero.
B. The heat added to the gas is different from the change in its internal energy.
C. The volume of the gas is increased.
D. The internal energy of the gas is increased.
E. The process is isochoric (constant volume process).
Choose the correct answer from the options given below:
1
A, B, C, D Only
2
A, D, E Only
3
E Only
4
A, C Only
117
PYQ 2025
medium
physics ID: jee-main
A container of fixed volume contains a gas at 27°C. To double the pressure of the gas, the temperature of the gas should be raised to °C.
118
PYQ 2025
medium
physics ID: jee-main
There are two vessels filled with an ideal gas where volume of one is double the volume of the other. The large vessel contains the gas at 8 kPa at 1000 K while the smaller vessel contains the gas at 7 kPa at 500 K. If the vessels are connected to each other by a thin tube allowing the gas to flow and the temperature of both vessels is maintained at 600 K, at steady state the pressure in the vessels will be (in kPa).
1
4.4
2
6
3
24
4
18
119
PYQ 2025
medium
physics ID: jee-main

An amount of ice of mass kg and temperature is transformed to vapor of temperature by applying heat. The total amount of work required for this conversion is,
(Take, specific heat of ice = 2100 J kg K ,
specific heat of water = 4180 J kg K ,
specific heat of steam = 1920 J kg K ,
Latent heat of ice = J kg ,
Latent heat of steam = J kg )

1
3022 J
2
3043 J
3
3003 J
4
3024 J
120
PYQ 2025
medium
physics ID: jee-main
A monoatomic gas is stored in a thermally insulated container. The gas is suddenly compressed to $ $ of its initial volume. Find the ratio of final pressure to initial pressure.
1
8
2
16
3
4
4
32
121
PYQ 2025
medium
physics ID: jee-main
The work done in an adiabatic change in an ideal gas depends upon:
1
change in its pressure
2
change in its volume
3
change in its specific heat
4
change in its temperature
122
PYQ 2025
medium
physics ID: jee-main
Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): With the increase in the pressure of an ideal gas, the volume falls off more rapidly in an isothermal process in comparison to the adiabatic process.
Reason (R): In an isothermal process, , while in an adiabatic process . Here, is the ratio of specific heats, is the pressure and is the volume of the ideal gas.
In the light of the above statements, choose the correct answer from the options given below:
1
Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
2
(A) is true but (R) is false
3
Both (A) and (R) are true and (R) is the correct explanation of (A)
4
(A) is false but (R) is true
123
PYQ 2025
medium
physics ID: jee-main
A poly-atomic molecule (C R, , where is gas constant) goes from phase space point A ( ) to point B ( ) to point C ( ). A to B is an adiabatic path and B to C is an isothermal path. The net heat absorbed per unit mole by the system is:
A poly-atomic molecule
1
500R( )
2
450R( )
3
500R( )
4
400R ln 2
124
PYQ 2025
medium
physics ID: jee-main
A monoatomic gas is stored in a thermally insulated container. The gas is suddenly compressed to th of its initial volume. Find the ratio of final pressure to initial pressure.
1
8
2
16
3
4
4
32
125
PYQ 2025
medium
physics ID: jee-main

Match List-I with List-II.

1
(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
2
(A)-(IV), (B)-(I), (C)-(III), (D)-(II)
3
(A)-(IV), (B)-(II), (C)-(III), (D)-(I)
4
(A)-(I), (B)-(II), (C)-(IV), (D)-(III)
126
PYQ 2025
medium
physics ID: jee-main
For a diatomic gas, if for rigid molecules and for another diatomic molecules, but also having vibrational modes. Then, which one of the following options is correct? (where and are specific heats of the gas at constant pressure and volume)
1

2

3

4

127
PYQ 2025
medium
physics ID: jee-main
Identify the characteristics of an adiabatic process in a monatomic gas. (A) Internal energy is constant. (B) Work done in the process is equal to the change in internal energy. (C) The product of temperature and volume is a constant. (D) The product of pressure and volume is a constant. (E) The work done to change the temperature from to is proportional to . Choose the correct answer from the options given below:
1
(A), (C), (D) only
2
(A), (C), (E) only
3
(B), (E) only
4
(B), (D) only
128
PYQ 2025
medium
physics ID: jee-main

is the specific heat ratio of monoatomic gas A having 3 translational degrees of freedom. is the specific heat ratio of polyatomic gas B having 3 translational, 3 rotational degrees of freedom and 1 vibrational mode. If then the value of is ___.

129
PYQ 2025
medium
physics ID: jee-main
The temperature of 1 mole of an ideal monoatomic gas is increased by at constant pressure. The total heat added and change in internal energy are and , respectively. If , then the value of is:
130
PYQ 2026
medium
physics ID: jee-main
An ideal gas undergoes a process maintaining relation between pressure ( ) and volume ( ) as , where and are constants. If two samples A and B (two moles each) with initial volumes and respectively undergo above mentioned process and attain same pressure, then the difference at the temperatures of these samples, is ______. ( = gas constant)
1

2

3

4
131
PYQ 2026
medium
physics ID: jee-main
A certain gas is isothermally compressed to of its initial volume ( litre) by applying required pressure. If the bulk modulus of the gas is , the magnitude of work done on the gas is ____ J.
132
PYQ 2026
hard
physics ID: jee-main
When 300 J of heat is given to an ideal gas with , its temperature rises from 20°C to 50°C keeping its volume constant. The mass of the gas is (approximately) ______ g. (R = 8.314 J/mol K)
133
PYQ 2026
hard
physics ID: jee-main

Which of the following best represents the temperature versus heat supplied graph for water, in the range of to ?

1
Graph 1
2
Graph 2
3
Graph 3
4
Graph 4
134
PYQ 2026
medium
physics ID: jee-main
An ideal gas has number of moles , initial volume and pressure The gas goes from state (initial) to (final) such that volume becomes . Find .
1

2

3

4
135
PYQ 2026
medium
physics ID: jee-main
5 moles of unknown gas is heated at constant volume from 10°C to 20°C. The molar specific heat of this gas at constant pressure cal/mol·°C and J/mol·°C. The change in the internal energy of the gas is _______ calorie.}
136
PYQ 2026
medium
physics ID: jee-main
Hydrolysis of sucrose follows 1st order kinetics to produce glucose and fructose. If for decomposition of sucrose is 3 hr, find the % of sucrose left after 6 hr.
137
PYQ 2026
easy
physics ID: jee-main
Find the final temperature of a mixture of two gases. If one gas has pressure , temperature , number of moles and volume ; and the second gas has pressure , temperature , number of moles and volume . If the final pressure is and final volume is , find the final temperature of the mixture.
1

2

3

4
138
PYQ 2026
medium
physics ID: jee-main
Bulk modulus of an ideal gas for isothermal process initially is . Gas is compressed from volume to isothermally. Find the work done by gas.
1

2

3

4
139
PYQ 2026
medium
physics ID: jee-main
10 mole of an ideal gas is undergoing the process shown in the figure. The heat involved in the process from to is Joule . The value of is ________.
1
15
2
21
3
28
4
24
140
PYQ 2026
easy
physics ID: jee-main
A 20 m long uniform copper wire held horizontally is allowed to fall under the gravity (g = 10 m/s²) through a uniform horizontal magnetic field of 0.5 Gauss perpendicular to the length of the wire. The induced EMF across the wire when it travels a vertical distance of 200 m is_______ mV.}
1
0.2√10
2
200√10
3
2√10
4
20√10
141
PYQ 2026
medium
physics ID: jee-main
10 kg of ice at is added to 100 kg of water to lower its temperature from . Consider no heat exchange to surroundings. The decrement in the temperature of water is ________ . (Specific heat of ice , specific heat of water , latent heat of fusion of ice )
1
2
3
4
142
PYQ 2026
medium
physics ID: jee-main
Match the column with the correct numerical values of energy/heat in column-II (R is universal gas constant)
1
A R; B P; C Q
2
A P; B R; C Q
3
A R; B Q; C P
4
A Q; B P; C R
143
PYQ 2026
hard
physics ID: jee-main
Internal energy of a gas is given as U = 3nRT. 1 mole of He gas takes 126 J of heat and its temperature rises by 4°C. Atmospheric pressure is Pa and area of piston is 17 cm . Find distance moved by piston.
1
18.5 cm
2
21.3 cm
3
12.3 cm
4
10.2 cm
144
PYQ 2026
medium
physics ID: jee-main
An ideal gas of 5 moles has . If its temperature changes from 10°C to 20°C, then calculate the change in its internal energy (in cal).
145
PYQ 2026
medium
physics ID: jee-main

Find heat given to gas to take it from A to B. (Given: S.I. units, Pa, Pa, S.I. units, moles)

1
J
2
J
3
J
4
J
146
PYQ 2026
hard
physics ID: jee-main
Sixty four rain drops of radius each falling down with a terminal velocity of coalesce to form a bigger drop. The terminal velocity of the bigger drop is ___ cm/s.
147
PYQ 2026
easy
physics ID: jee-main
A container of initial volume is expanded adiabatically from pressure 8 bar to final pressure 1 bar. If initial temperature is , then find work done by the gas :- ( ) :-
148
PYQ 2026
medium
physics ID: jee-main
As shown in the figure, six rods of same geometry are connected and maintained at temperatures and . The temperature at points and are:
1
2
3
4
149
PYQ 2026
medium
physics ID: jee-main
Density of water at 4 C is 1000 kg/m and at 20 C it is 998 kg/m . If 4kg of water is heated from 4 C to 20 C, the change in internal energy of water is : (Given : specific heat capacity of water = 4200 J/kg K, Atmospheric pressure P = Pa).
1
268799.2 J
2
268800.8 J
3
268800.0 J
4
267765.2 J
150
PYQ 2026
medium
physics ID: jee-main
In a Young's double slit experiment set up, the two slits are kept 0.4 mm apart and screen is placed at 1 m from slits. If a thin transparent sheet of thickness 20 m is introduced in front of one of the slits then center bright fringe shifts by 20 mm on the screen. The refractive index of transparent sheet is given by , where is _________}.
151
PYQ 2026
hard
physics ID: jee-main
A simple pendulum of string length 30 cm performs 20 oscillations in 10 s. The length of the string required for the pendulum to perform 40 oscillations in the same time duration is_______ cm. [Assume that the mass of the pendulum remains same]}
1
7.5
2
120
3
0.75
4
15
152
PYQ 2026
easy
physics ID: jee-main
An insulated cylinder of volume is filled with a gas at and atmospheric pressure. The gas is then compressed making the final volume while allowing the temperature to rise to . The final pressure is ____________ atmospheric pressure.
153
PYQ 2026
medium
physics ID: jee-main
For diatomic gas, find the ratio for isobaric process :-
1
2 : 5 : 7
2
2 : 3 : 5
3
2 : 7 : 3
4
7 : 5 : 2
154
PYQ 2026
easy
physics ID: jee-main
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Consider a ferromagnetic material :
Assertion (A): The individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact with one another in such a way that they spontaneously align themselves forming domains.
Reason (R): At high enough temperature, the domain structure of ferromagnetic material disintegrates. Thus, magnetization will disappear at high enough temperature known as Curie temperature.
In the light of the above statements, choose the correct answer from the options given below :
1
(A) is false but (R) is true
2
Both (A) and (R) are true but (R) is not the correct explanation of (A)
3
Both (A) and (R) are true and (R) is the correct explanation of (A)
4
(A) is true but (R) is false
155
PYQ 2026
hard
physics ID: jee-main

In the following diagram, the equation of state along the curved path is given by where is a constant. The total work done in the closed path is:

1
2
3
4
156
PYQ 2026
easy
physics ID: jee-main
300 J of energy is given to a gas at constant volume which increases its temperature from C to C. If S.I. units and , find mass of gas.
157
PYQ 2026
hard
physics ID: jee-main
An ideal gas in a closed rigid container is at 50 C and pressure 3.23 kPa. If temperature is doubled, find new pressure in Pa :
1
3730 Pa
2
3230 Pa
3
6460 Pa
4
6430 Pa
158
PYQ 2026
hard
physics ID: jee-main

For a gas P-V curve is given as shown in the diagram. Curve path follows equations . Find work done by gas in given cyclic process.

1

2

3

4

159
PYQ 2026
medium
physics ID: jee-main
An air bubble inside water at depth h = 5 m rises to surface. At bottom temperature is and volume is . At the surface the temperature is . Find final volume (Given that number of moles remains same and Pa, and g=10 m/s ):
1
2
3
4

160
PYQ 2026
medium
physics ID: jee-main
Hydrogen and oxygen gases have the same RMS speed. If hydrogen gas is at , find the temperature of oxygen gas.
1
2
3
4

161
PYQ 2026
medium
physics ID: jee-main
Find work done by gas in cyclic process:
1
2
3
4
162
PYQ 2026
medium
physics ID: jee-main
Match List-I (Isothermal Process) with List-II (work done)
1
2
3
4

163
PYQ 2026
medium
physics ID: jee-main
One mole of a diatomic gas is expanding isothermally from V to 2V at 27°C. If the magnitude of work done by gas in this case is same as the work done in an adiabatic process where initial temperature is 27°C and final temperature is T. Find T in °C.
1
-37°C
2
-57°C
3
-35°C
4
-55°C
164
PYQ 2026
medium
physics ID: jee-main
For an ideal gas in a reversible process ( ), volume becomes times and temperature becomes times the initial value. Identify the gas:
1
2
3
4
165
PYQ 2026
medium
physics ID: jee-main
For the following change, Select the correct answer:
1
2
3
4
166
PYQ 2026
easy
physics ID: jee-main
In an adiabatic process, the temperature reduces to th and volume increases to 8 times. Find the adiabatic constant of the gas.
1
2
3
4

167
PYQ 2026
medium
physics ID: jee-main

Two balls made of the same material collide perfectly inelastically as shown. The energy lost in the collision is completely utilized in raising the temperature of each ball. Find the rise in temperature of the balls. (Specific heat cal/kg- C):

1
C
2
C
3
C
4
C
168
PYQ 2026
medium
physics ID: jee-main
A brass rod is fixed rigidly at two ends at 27 C. If it is cooled to temperature -43 C, tension in rod becomes T . Find temperature (in C) at which tension will be 1.4 T :
1
-71 C
2
-65 C
3
-50 C
4
-82 C
169
PYQ 2026
medium
physics ID: jee-main
of water is heated from to at constant pressure so that density changes from to . Then find (in ) given of :
1
2
3
4

170
PYQ 2026
easy
physics ID: jee-main

Two rods of equal length each are joined together end to end. The coefficients of linear expansion of the rods are and . Their initial temperature is , which is increased to . Find the final length of the combination (in cm).

1
2
3
4
171
PYQ 2026
medium
physics ID: jee-main
Find the change in internal energy of a gas if its temperature changes by . Number of moles of gas is , (specific heat at constant pressure) is and (gas constant) .
1
2
3
4
172
PYQ 2026
medium
physics ID: jee-main
The temperature of 5 moles of an ideal gas increases by 20 K.
Given:
,
The change in internal energy of the gas is:
1
500 cal
2
700 cal
3
800 cal
4
900 cal
173
PYQ 2026
medium
physics ID: jee-main
Find the change in internal energy of gas if its temperature changes by 10K. Number of moles of gas is 10, (specific heat at constant pressure of the gas) is 7 cal/K-mol and (gas constant) = 2 cal/K.
1
500 cal
2
1000 cal
3
250 cal
4
100 cal
174
PYQ 2026
easy
physics ID: jee-main
Find change in internal energy of gas if its temperature changes by K. Number of moles of gas is . (specific heat at constant pressure) of the gas is cal/K-mol and (gas constant) is cal/K.
1
cal
2
cal
3
cal
4
cal