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 2 of 36
- A. Internal energy
- B. work and heat
- C. Enthalpy
- D. Entropy
Explanation: Heat and work depend on the path followed during a process, so they are path functions, whereas internal energy, enthalpy and entropy are…
Correct answer: work and heat22. The system which can exchange matter as well as energy with its surroundings is called____________?
- A. open system
- B. Closed system
- C. Isolated system
- D. Inert system
Explanation: An open system can exchange both matter and energy with its surroundings, such as steam flowing through a turbine.
Correct answer: open system- A. Isochoric
- B. Isobaric
- C. adiabatic
- D. Isothermal
Explanation: An adiabatic process has no heat transfer, so Q = 0 J, although the system's temperature may still change because work can be done.
Correct answer: adiabatic- A. in adiabatic expansion
- B. in adiabatic compression
- C. in isothermal expansion
- D. in isothermal compression
Explanation: In an adiabatic process, heat transfer is zero, so the work done on the gas changes its internal energy.
Correct answer: in adiabatic compression- A. isothermal
- B. isochoric
- C. isobaric
- D. isentropic
Explanation: For an ideal gas in an isothermal process, temperature and therefore internal energy remain constant, so the first law gives Q = W.
Correct answer: isothermal- A. cyclic process
- B. operated at certain temperature difference
- C. both A and B
- D. none of these
Explanation: A heat engine must operate cyclically so that its working substance returns to its initial state, and it needs a temperature difference…
Correct answer: both A and B- A. constant
- B. variable
- C. zero
- D. depends on situation
Explanation: In an isochoric process, volume remains constant, so the work W = integral of P dV is zero because dV = 0.
Correct answer: zero- A. It is sum of all forms of energies associated with molecules of a system
- B. It is a state function of a system
- C. It is proportional to transnational K.E of the molecules
- D. All are correct
Explanation: Internal energy is the total microscopic energy of a system, including molecular kinetic and potential energies, and it is a state…
Correct answer: All are correct- A. rapid escape of air from a burst tyre
- B. rapid expansion of air
- C. conversion of water into ice in refrigerator
- D. cloud formation in the atmosphere
Explanation: An adiabatic process involves no appreciable heat exchange, which is possible during rapid expansion, rapid air escape, and some…
Correct answer: conversion of water into ice in refrigerator- A. 8.314 J/mole K
- B. 6.5 J/mole K
- C. 1.314 J/mole K
- D. 10.314 J/mole K
Explanation: The universal gas constant has the value R = 8.314 J mol^-1 K^-1, equivalently 8.314 J/(mol K).
Correct answer: 8.314 J/mole K- A. Water
- B. Alcohol
- C. Methane
- D. Kerosene
Explanation: On a mass basis, water has a very high specific heat capacity, about 4.18 kJ/kg·K, compared with alcohol, methane, and kerosene under…
Correct answer: Water- A. Sudden compression of gases
- B. Sudden expansion of gases
- C. Cooling of gases
- D. Heating of gases
Explanation: The Joule-Thomson effect occurs when a real gas undergoes throttling, usually through a porous plug or narrow valve, causing a pressure…
Correct answer: Sudden expansion of gases- A. 1.67
- B. 1.4
- C. γ = 1.3
- D. None
Explanation: For a diatomic ideal gas at ordinary temperatures, gamma = Cp/Cv = 7/5 = 1.4 because the molecules have translational and rotational…
Correct answer: 1.4- A. 3NaT/2R
- B. 2NaT/3
- C. 3RT/2Na
- D. 3Na/2RT
Explanation: The average translational kinetic energy per molecule is 3kT/2, and k = R/Na, so it becomes 3RT/(2Na) joules per molecule.
Correct answer: 3RT/2Na- A. K = RNa
- B. K = R/Na
- C. K = Na/Ra
- D. K = nRNa
Explanation: Boltzmann's constant is the gas constant per molecule, so k = R/Na. For example, R has units J mol^-1 K^-1 and Na has units mol^-1, giving…
Correct answer: K = R/Na36. 1atm is equal to
- A. 760 torr
- B. 760 mmHg
- C. 101.3 kPa
- D. all of the above
Explanation: The standard atmospheric pressure is 1 atm = 760 torr = 760 mmHg = 101.3 kPa.
Correct answer: all of the above- A. Base quantities
- B. Derived quantities
- C. Prefixes
- D. Quartile quantities
Explanation: Length, mass, time, luminous intensity and amount of substance are SI base quantities because their units are fundamental and are not…
Correct answer: Base quantities- A. ΔL = αLΔT
- B. ΔL/LΔT
- C. LΔT/ΔL
- D. αLΔT-ΔL
Explanation: From linear expansion, ΔL = αLΔT, so the coefficient is α = ΔL/(LΔT), with unit K^-1.
Correct answer: ΔL/LΔT- A. Decreases
- B. Increases
- C. Remains same
- D. Becomes Zero
Explanation: A liquid boils when its vapour pressure equals the surrounding pressure.
Correct answer: Increases- A. momentum
- B. mass
- C. velocity
- D. kinetic energy
Explanation: The mean translational kinetic energy of a gas molecule is 3kT/2, so at the same temperature it has the same average value for all ideal…
Correct answer: kinetic energy