Free Thermodynamics MCQs with Answers
714 Thermodynamics MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Thermal equilibrium and heat explain how temperature and energy transfer are related, while molar specific heats describe the heat required by a gas at constant volume or constant pressure. The first law connects heat supplied, work done and change in internal energy, with sign conventions kept distinct from temperature changes.
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Read the Thermodynamics notesFree MDCAT chapter notes with key terms714 questions · page 29 of 36
- A. Risen
- B. Decreased
- C. Remained constant
- D. Cannot be determined
Explanation: This is the correct answer. When a gas is compressed in a thermally insulated container (adiabatic process), work is done on the gas.
Correct answer: Risen- A. ΔW=ΔQ+ΔU
- B. ΔU=ΔW-ΔQ
- C. ΔQ=ΔW-ΔU
- D. ΔQ=ΔU-ΔW
- E. ΔU = ΔQ-ΔW
Explanation: Option E is the correct representation of first law of thermodynamics.
Correct answer: ΔU = ΔQ-ΔW- A. Heat flows out of the system
- B. Work is done by the system
- C. Work is done by the surrounding
- D. The potential energy of the system is changing
Explanation: By first law of Thermodynamics, Q= U + WQ= heat energy supplied to the systemU= internal energyW= Work done by the systemIf work is done…
Correct answer: Work is done by the system- A. Work
- B. Entropy
- C. Heat
Explanation: As the first law of thermodynamics is given byΔU = ΔQ - ΔWwhere ΔU is the change in internal energyΔQ is the heat addedand ΔW is the work…
Correct answer: Heat- A. nR/(y-1)(T1-T2)
- B. nR/(y-1)(T2-T1)
- C. nR(T2-T1)
- D. R(T2-T1)
Explanation: Option A is correct since it gives the correct statement for the work done in an adiabatic process.Option B is incorrect since it does not…
Correct answer: nR/(y-1)(T1-T2)- A. It is sum of all forms of molecular energies of a system
- B. It is proportional to translational K.E of the molecules
- C. It is a state function of a system
- D. All are correct
Explanation: All options are related to internal energy. Internal energy of a system with well defined boundaries, is the total of the kinetic energy…
Correct answer: All are correct- A. 8200J
- B. 5600J
- C. 7900J
- D. 6400J
Explanation: The change in internal energy (∆U) of a system can be found using the First Law of Thermodynamics: ∆U = ∆Q - ∆W, where ∆Q is the heat…
Correct answer: 7900J- A. T increases
- B. Mechanical energy comes into the system
- C. ∆Q= Zero
- D. All of these
Explanation: The correct answer is D because during an adiabatic contraction:A) The temperature (T) of the system increases.B) Mechanical energy comes…
Correct answer: All of these- A. The heating of a system equal to the increase of its internal energy plus the work done on the system
- B. The increase in the internal energy of a system equal to the heating of the system minus the work done by the system
- C. The increase in the internal energy of system equal to the heating of the system plus the work done by the system
- D. The work done on a system equals the increase of its theramal energy plus the heating of the system
Explanation: Statement of first law of thermodynamics states the increase in the internal energy of a system equal to the heating of the system minus…
Correct answer: The increase in the internal energy of a system equal to the heating of the system minus the work done by the system- A. 31.4J
- B. 3.14 x 10^6J
- C. 3.14J
- D. None
Explanation: Q=∆U+W cyclic process i.e. ∆U=0 Q=W=Area pf P-V graph= πr² =π(Pr)(Vr) =3.14(100x103)(100)=31.4x106 J
Correct answer: 3.14 x 10^6J- A. -100J
- B. 0 J
- C. +100 J
- D. None
Explanation: The correct answer is C because in an adiabatic process, there is no heat exchange (Q = 0) between the gas and its surroundings.
Correct answer: +100 J- A. Isothermal expansion
- B. Energy dissipiation
- C. Adiabatic expansion
- D. Adiabatic compression
Explanation: Adiabatic expansion is a type of expansion in which no heat is exchanged with the surroundings.
Correct answer: Adiabatic expansion- A. Must remain same
- B. May fall
- C. May rise
- D. Both B & C
Explanation: If heat neither enters nor leaves a system, then its temperature may rise or may fall.
Correct answer: Both B & C- A. Cp −Cv =R
- B. CP /Cv =γ
- C. Cv −Cp =R
- D. Both a and b
Explanation: Both options (a) and (b) are correct. The first one (Cp −Cv =R) represents the difference between the molar-specific heat capacities at…
Correct answer: Both a and b- A. 2 / 5 R
- B. 2 / 7 R
- C. 5 / 2 R
- D. 7 / 2 R
Explanation: Since Cp - Cv = Rhence , X - 5/2 R = RX = 7/2 R
Correct answer: 7 / 2 R- A. 82.5 Cal
- B. 80 Cal
- C. 85.2 Cal
- D. 58.8 Cal
Explanation: Cp and CV for a diatomic gas is 7/2 R and 5/2 R respectively. The gas's internal energy is increase by only 0.71 of the supplied energy.
Correct answer: 85.2 Cal- A. Diatomic
- B. Mixture of diatomic and polyatomic
- C. Mono atomic
- D. Polyatomic
Explanation: The correct answer is C because a gas with (R/Cv) = 0.67 indicates that the gas behaves as a monoatomic gas.
Correct answer: Mono atomic- A. The temperatures of water at 0°C and 100°C
- B. The temperature of melting ice and boiling water at atmospheric pressure
- C. The temperatures of ice cold and boiling water
- D. The temperatures of frozen and boiling mercury
Explanation: The temperature of melting ice and boiling water at atmospheric pressure are 0°C and 100°C respectively.
Correct answer: The temperature of melting ice and boiling water at atmospheric pressure- A. 410⁰C
- B. 37⁰ C
- C. 42⁰C
- D. 55⁰C
Explanation: The formula to convert temperature from Fahrenheit (°F) to Celsius (°C) is:°C= 5/9 x (°F - 32)°C= 5/9 x (°98.6 - 32)°C=37°C
Correct answer: 37⁰ C- A. efficiency
- B. coefficient of performance
- C. both a and b
- D. not describe
Explanation: A heat engine works by utilizing a cyclic process, where it continuously operates in a repeating sequence.Additionally, a heat engine…
Correct answer: efficiency