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Thermodynamics Questions

Practice 174 Thermodynamics questions with detailed answers and explanations. Free MCQs, PYQs, and mock test questions for NEET, JEE, GATE, SSC and more.

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29
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121
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24
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Practice by Exam:Physics(97)Chemistry(72)CHEMISTRY(2)General Knowledge and General Awareness(2)PHYSICS(1)

About Thermodynamics — practice questions, PYQs & concepts

Thermodynamics is a frequently-tested topic on Physics, Chemistry, CHEMISTRY. ExamTest.live currently lists 174 Thermodynamics questions spanning previous-year papers from 2026 to 2026, each with worked solutions and a step-by-step explanation. Use the filters on this page to focus on a specific exam, difficulty level or year — every answer key is free, no sign-up required.

Thermodynamics weight in competitive exams

Across our Thermodynamics question bank, the largest sources are Physics (97), Chemistry (72), CHEMISTRY (2), General Knowledge and General Awareness (2) and PHYSICS (1). Click any exam chip above to drill down to that exam-specific question set.

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All Thermodynamics Questions(1–100 of 174)

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Q1mediummcqChemistryAIEEE2026
0% accuracy
For a spontaneous reaction the , equilibrium constant () and will be respectively:
Q2hardmcqPhysicsAIEEE 20042026
0% accuracy
One mole of ideal monoatomic gas () is mixed with one mole of diatomic gas (). What is for the mixture? denotes the ratio of specific heat at constant pressure to that at constant volume.
Q3easymcqPhysicsAIEEE 20042026
50% accuracy
Which of the following statements is correct for any thermodynamic system?
Q4mediummcqPhysicsAIEEE 20042026
0% accuracy
A radiation of energy falls normally on a perfectly reflecting surface. The momentum transferred to the surface is:
Q5hardmcqChemistryAIEEE2026
0% accuracy
If the bond dissociation energies of and are in the ratio and for is , the bond dissociation energy of will be:
Q6mediummcqChemistryAIEEE2026
0% accuracy
Consider the reaction: carried out at constant temperature and pressure. If and are the enthalpy and internal energy changes for the reaction, which of the following expressions is true?
Q7mediummcqChemistryAIEEE2026
0% accuracy
A schematic plot of versus inverse of temperature () for a reaction is shown below. The reaction must be:
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Q8mediummcqPhysicsAIEEE 20042026
0% accuracy
If the temperature of the sun were to increase from to and its radius from to , then the ratio of the radiant energy received on earth to what it was previously will be:
Q9mediummcqPhysicsAIEEE 20042026
0% accuracy
The temperature of two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity and and thickness and respectively, are and (). The rate of heat transfer through the slab in a steady state is , where is:
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Q10hardmcqPhysicsAIEEE 20042026
0% accuracy
Two thermally insulated vessels and are filled with air at temperatures , volume and pressure respectively. If the valve joining the two vessels is opened, the temperature inside the vessel at equilibrium will be:
Q11mediummcqPhysicsAIEEE 20062026
0% accuracy
Assuming the sun to be a spherical body of radius at a temperature of , evaluate the total radiant power incident on Earth at a distance from the Sun. (where is the radius of the Earth and is Stefan’s constant).
Q12mediummcqChemistryAIEEE 20072026
0% accuracy
The energies of activation for forward and reverse reactions for are and respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by . The enthalpy change of the reaction () in the presence of catalyst will be (in ):
Q13mediummcqChemistryNEET (UG) 20172026
0% accuracy
A gas expands in a well insulated container against a constant external pressure of from an initial volume of to a final volume of . The change in internal energy of the gas in joules will be:
Q14easymcqPhysicsNEET 20192026
0% accuracy
In which of the following processes, heat is neither absorbed nor released by a system?
Q15mediummcqPhysicsAIEEE 20072026
0% accuracy
If and denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively, then:
Q16easymcqChemistryNEET 20192026
0% accuracy
Under isothermal condition, a gas at 300K expands from 0.1L to 0.25L against a constant external pressure of 2bar. The work done by the gas is (Given that 1L bar=100J):
Q17mediummcqChemistryAIEEE 20062026
0% accuracy
An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If is the initial temperature and is the final temperature, which of the following statements is correct?
Q18easymcqChemistryAIEEE 20062026
0% accuracy
() for the formation of carbon monoxide () from its elements at is ():
Q19mediummcqPhysicsNEET (UG) 20172026
0% accuracy
A Carnot engine having an efficiency of as a heat engine, is used as a refrigerator. If the work done on the system is , the amount of energy absorbed from the reservoir at lower temperature is:
Q20mediummcqPhysicsAIEEE 20072026
0% accuracy
When a system is taken from state to state along the path , it is found that and . Along the path , . along the path is:
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Q21mediummcqPhysicsAIEEE 20072026
0% accuracy
A Carnot engine, having an efficiency of as a heat engine, is used as a refrigerator. If the work done on the system is , the amount of energy absorbed from the reservoir at lower temperature is:
Q22hardmcqPhysicsAIEEE 20062026
0% accuracy
Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature , while Box B contains one mole of helium at temperature . The boxes are put into thermal contact. The final temperature is:
Q23mediummcqPhysicsAIEEE 20062026
0% accuracy
Work of is performed in order to compress one kilo mole of gas adiabatically and in this process the temperature of the gas increases by . The gas is: ()
Q24mediummcqChemistryNEET (UG) 20172026
0% accuracy
For a given reaction, and . The reaction is spontaneous at: (Assume that and do not vary with temperature)
Q25mediummcqPhysicsNEET (UG) 20172026
0% accuracy
Match the following thermodynamic processes with their diagram characteristics:
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Q26mediummcqChemistryNEET 20192026
0% accuracy
A gas at 350K and 15bar has molar volume 20 percent smaller than that for an ideal gas under the same conditions. The correct option about the gas and its compressibility factor (Z) is:
Q27easymcqPhysicsNEET 20192026
0% accuracy
Increase in temperature of a gas filled in a container would lead to:
Q28easymcqChemistryNEET 20192026
0% accuracy
In which case change in entropy is negative?
Q29mediummcqGeneral Knowledge and General AwarenessSSC CPO 20242026
0% accuracy
Which phenomenon is the exact opposite of solidification?
Q30mediummcqPhysicsAIEEE 20092026
Referring to the diagram in the previous question, the work done on the gas in taking it from to is:
Q31mediummcqPhysicsAIEEE 20092026
Directions: Question numbers 28, 29 and 30 are based on the following paragraph. Two moles of helium gas are taken over the cycle ABCDA, as shown in the P – T diagram.
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Two moles of helium gas are taken over the cycle , as shown in the diagram. Assuming the gas to be ideal, the work done on the gas in taking it from to is:
Q32mediummcqPhysicsAIEEE2026
Two chambers and are separated by an insulating partition. If the partition is removed, the final equilibrium temperature is:
Q33mediummcqChemistryAIEEE2026
Oxidizing power of chlorine in aqueous solution can be determined by the parameters: Using the data: The energy involved in the conversion of to will be:
Q34mediummcqPhysicsAIEEE 20122026
Helium gas goes through a cycle (consisting of two isochoric and two isobaric lines) as shown in figure. The pressure and volume at are and at are . Efficiency of this cycle is nearly:
image
Q35mediummcqChemistryAIEEE2026
For a particular reversible reaction at temperature , and were found to be both . If is the temperature at equilibrium, the reaction would be spontaneous when:
Q36mediummcqChemistryAIEEE2026
Standard entropy of , and are , and , respectively. For the reaction , . For the reaction to be at equilibrium, the temperature will be:
Q37mediummcqPhysicsFIITJEE AIEEE 2011 (Set Q)2026
of water is heated from to . Ignoring the slight expansion of the water, the change in its internal energy is (specific heat of water is ):
Q38mediummcqPhysicsFIITJEE AIEEE 2011 (Set Q)2026
A Carnot engine operating between temperatures and has efficiency . When is lowered by , its efficiency increases to . Then and are, respectively:
Q39mediummcqPhysicsNEET 20172026
A gas mixture consists of moles of and moles of at temperature . Neglecting all vibrational modes, the total internal energy of the system is:
Q40mediummcqChemistryAIEEE 20122026
The incorrect expression among the following is:
Q41hardmcqChemistryFIITJEE AIEEE 2011 (Set Q)2026
The entropy change involved in the isothermal reversible expansion of of an ideal gas from a volume of to a volume of at is:
Q42mediummcqPhysicsNEET 20172026
Thermodynamic processes are indicated in the following diagram.
image
Match the following:
image
Q43mediummcqPhysicsNEET 20172026
A Carnot engine having an efficiency of as heat engine, is used as a refrigerator. If the work done on the system is , the amount of energy absorbed from the reservoir at lower temperature is:
Q44mediummcqChemistryNEET 20172026
A gas is allowed to expand in a well insulated container against a constant external pressure of from an initial volume of to a final volume of . The change in internal energy of the gas in joules will be:
Q45mediummcqChemistryNEET 20172026
For a given reaction, and . The reaction is spontaneous at (Assume that and do not vary with temperature):
Q46mediummcqChemistryAIEEE 20042026
The enthalpies of combustion of carbon and carbon monoxide are and respectively. The enthalpy of formation of carbon monoxide per mole is:
Q47mediummcqPhysicsNEET (UG) 20182026
The volume () of a monatomic gas varies with its temperature (), as shown in the graph (a straight line passing through the origin). The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is:
image
Q48mediummcqChemistryAIEEE 20042026
An ideal gas expands in volume from to at against a constant pressure of . The work done is:
Q49mediummcqPhysicsNEET (UG) 20182026
The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is:
Q50hardmcqChemistryNEET (UG) 20182026
The bond dissociation energies of and are in the ratio of . for the formation of is . The bond dissociation energy of will be:
Q51mediummcqPhysicsAIEEE 20032026
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio for the gas is:
Q52hardmcqPhysicsAIEEE 20032026
In the nuclear fusion reaction , given that the repulsive potential energy between the two nuclei is , the temperature at which the gases must be heated to initiate the reaction is nearly: (Boltzmann’s constant )
Q53easymcqPhysicsAIEEE 20032026
Which of the following parameters does not characterize the thermodynamic state of matter?
Q54mediummcqChemistryJEE Main2026
A piston filled with of an ideal gas expands reversibly from to at a constant temperature of . As it does so, it absorbs of heat. The values of and for the process will be ():
Q55easymcqPhysicsAIEEE 20122026
A liquid in a beaker has temperature at time and is temperature of surroundings, then according to Newton's law of cooling the correct graph between and is:
image
Q56mediummcqPhysicsFIITJEE AIEEE 2011 (Set Q)2026
Three perfect gases at absolute temperatures and are mixed. The masses of molecules are and and the number of molecules are and respectively. Assuming no loss of energy, the final temperature of the mixture is:
Q57easymcqPhysicsAIEEE 20032026
According to Newton’s law of cooling, the rate of cooling of a body is proportional to , where is the difference of the temperature of the body and the surroundings, and is equal to:
Q58hardmcqPHYSICSNEET 20192026
of water of volume at is converted into steam at the same temperature under normal atmospheric pressure . The volume of steam formed equals . If the specific latent heat of vaporization of water is , the change in internal energy is:
Q59mediummcqPhysicsAIEEE 20092026
Referring to the diagram, the net work done on the gas in the cycle is:
Q60mediummcqChemistryAIEEE 20092026
In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is . At standard Gibb’s energies of formation for , and are , and respectively. If standard enthalpy of combustion of methanol is , efficiency of the fuel cell will be:
Q61mediummcqPhysicsAIEEE 20092026
One kg of a diatomic gas is at a pressure of . The density of the gas is . What is the energy of the gas due to its thermal motion?
Q62mediummcqChemistryAIEEE2026
The standard enthalpy of formation of is . If the enthalpy of formation of from its atoms is and that of is , the average bond enthalpy of bond in is:
Q63hardmcqCHEMISTRYNEET 20192026
Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure (AB Isothermal, AC Adiabatic). Which of the following options is not correct?
image
Q64hardmcqChemistryNEET 2020 E12026
Hydrolysis of sucrose is given by the following reaction:

If the equilibrium constant () is at , the value of at the same temperature will be:
Q65mediummcqChemistryNEET 2020 E12026
The correct option for free expansion of an ideal gas under adiabatic condition is:
Q66mediummcqPhysicsAIEEE2026
A system goes from A to B via two processes I and II as shown in the figure. If and are the changes in internal energies in the processes I and II respectively, then:
image
Q67mediummcqPhysicsAIEEE2026
A gaseous mixture consists of of helium and of oxygen. The ratio of the mixture is:
Q68mediummcqPhysicsAIEEE2026
Which of the following is incorrect regarding the first law of thermodynamics?
Q69hardmcqChemistryNEET (UG) 20242026
The work done during reversible isothermal expansion of one mole of hydrogen gas at from a pressure of to is:(Given , )
Q70mediummcqChemistryNEET (UG) 20242026
In which of the following processes does entropy increase?(A) Liquid evaporating to vapor.(B) Lowering the temperature of a gas.(C) Decomposition of to , , and .(D) Dissociation of into .
Q71mediummcqPhysicsAIEEE2026
A diatomic ideal gas is used in a Carnot engine as the working substance. If during the adiabatic expansion part of the cycle, volume of the gas increases from to , the efficiency of the engine is:
Q72mediummcqGeneral Knowledge and General AwarenessPrepp2026
Which phenomenon is opposite to solidification?
Q73mediummcqPhysicsAIEEE 20032026
A carnot engine takes of heat from a reservoir at , and gives it to a sink at . The work done by the engine is:
Q74easymcqPhysicsAIEEE 20032026
The earth radiates in the infra-red region of the spectrum. The spectrum is correctly given by:
Q75mediummcqPhysicsNEET (UG) 20242026
The following graph represents the curves of an ideal gas at three pressures and .
image
Then the correct relation is:
Q76easymcqChemistryNEET (UG) 20242026
Match List I with List II:
| List I (Process) | List II (Conditions) |
| (A) Isothermal process | (I) No heat exchange |
| (B) Isochoric process | (II) Carried out at constant temperature |
| (C) Isobaric process | (III) Carried out at constant volume |
| (D) Adiabatic process | (IV) Carried out at constant pressure |
Q77mediummcqChemistryNEET 20232026
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:Assertion A: In the equation , the value of depends on .Reason R: is an intensive property and is an extensive property.In the light of the above statements, choose the correct answer:
Q78easymcqChemistryNEET 20232026
Which amongst the following options is the correct relation between change in enthalpy and change in internal energy?
Q79mediummcqPhysicsNEET 20232026
The temperature of gas is . To what temperature the gas should be heated so that the RMS speed is increased by times?
Q80mediummcqPhysicsFIITJEE AIEEE 2011 (Set Q)2026
A thermally insulated vessel contains an ideal gas of molecular mass and ratio of specific heats . It is moving with speed and is suddenly brought to rest. Assuming no heat is lost to the surroundings, its temperature increases by:
Q81mediummcqChemistryNEET 20222026
Which of the following curves represents maximum work done?
(1)
image
image
Q82hardmcqPhysicsNEET (UG) 20182026
A sample of of water at and normal pressure () requires of heat energy to convert to steam at . If the volume of the steam produced is , the change in internal energy of the sample, is:
Q83easymcqPhysicsAIEEE 20032026
"Heat cannot by itself flow from a body at lower temperature to a body at higher temperature" is a statement of consequence of:
Q84hardmcqChemistryNEET 20232026
The equilibrium concentrations of the species in the reaction are and , respectively at . for the reaction is ():
Q85mediummcqPhysicsNEET 20232026
A Carnot engine has an efficiency of when its source is at a temperature . The temperature of the sink is:
Q86mediummcqPhysicsNEET 20222026
An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic, isothermal, isobaric and isochoric. The curve which represents the adiabatic process among 1, 2, 3 and 4 is:
image
Q87easymcqPhysicsNEET 20212026
Match Column-I and Column-II and choose the correct match from the given choices.
image
Q88easymcqChemistryNEET 20212026
Which one among the following is the correct option for right relationship between and for one mole of ideal gas?
Q89hardmcqPhysicsNEET 2020 E12026
Two cylinders and of equal capacity are connected to each other via a stop cock. contains an ideal gas at standard temperature and pressure. is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is:
Q90mediummcqCHEMISTRYNEET 20192026
An ideal gas expands isothermally from to at against a constant pressure of . The work done by the gas is:
Q91mediummcqPhysicsAIEEE2026
The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is:
image
Q92mediummcqPhysicsAIEEE2026
The figure shows a system of two concentric spheres of radii and and kept at temperatures and respectively. The radial rate of flow of heat in a substance between the two concentric sphere is proportional to:
image
Q93mediummcqChemistryNEET 20212026
For irreversible expansion of an ideal gas under isothermal condition, the correct option is:
Q94mediummcqPhysicsJEE Main2026
An ideal gas enclosed in a vertical cylindrical container supports a freely moving piston of mass . The piston and cylinder have equal cross sectional area . When the piston is in equilibrium, the volume of the gas is and its pressure is . The piston is slightly displaced from the equilibrium position and released. Assuming that the system is completely isolated from its surrounding, the piston executes a simple harmonic motion with frequency:
Q95mediummcqPhysicsJEE Main2026
image
A diagram represents the thermodynamic cycle of an engine, operating with an ideal monoatomic gas. The cycle is a rectangle with vertices . The amount of heat extracted from the source in a single cycle is:
Q96mediummcqPhysicsAIEEE 20122026
A Carnot engine, whose efficiency is , takes in heat from a source maintained at a temperature of . It is desired to have an engine of efficiency . Then, the intake temperature for the same exhaust (sink) temperature must be:
Q97easymcqPhysicsNEET (UG) 20242026
A thermodynamic system is taken through the cycle . The work done by the gas along the path is:
image
Q98mediummcqChemistryNEET 2020 E12026
For the reaction, , the correct option is:
Q99mediummcqChemistryChemistry
0% accuracy
. Which of the following diagrams gives an accurate representation of the above reaction? [ reactants; products]
Q100hardmcqPhysicsPhysics
0% accuracy
A container has two chambers of volumes and separated by a partition made of a thermal insulator. The chambers contains and moles of ideal gas at pressures and , respectively. When the partition is removed, the mixture attains an equilibrium pressure of:
12

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