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 34 of 36
- A. Adiabatic processes
- B. Isothermal process
- C. Cooling process
- D. First law of thermodynamics
Explanation: The burst of a tire is a sudden process. The process occurs instantaneously, such that the system does not get sufficient time to exchange…
Correct answer: Adiabatic processes- A. Q = W
- B. W = -U
- C. Q = -ΔU
- D. Q = ΔU + W
Explanation: An isothermal process is a thermodynamic process in which the temperature of a system remains constant.
Correct answer: Q = W- A. 50%
- B. 70%
- C. 90%
- D. 95%
Explanation: The efficiency of a Carnot engine is entirely a function of the temperatures of the hot and cold reservoirs you use.
Correct answer: 50%- A. Constant temperature
- B. Constant pressure
- C. Constant volume
- D. Constant temperature and constant pressure
Explanation: Isobaric process is a process in which the change in pressure is 0 i.e.
Correct answer: Constant pressure- A. 8.314 Jmol-1K-1
- B. 8.324 Jmol-1K-1
- C. 7.23 Jmol-1K-1
- D. 1.00 Jmol-1K-1
Explanation: The correct value of the universal gas constant is 8.314 J/mol·K, which is used in the ideal gas law equation PV=nRT.
Correct answer: 8.314 Jmol-1K-1- A. 50%
- B. 40%
- C. 60%
- D. 70%
Explanation: To find the maximum possible efficiency of the steam turbine, we use the Carnot efficiency formula: η = (T1 - T2) / T1, where T1 and T2…
Correct answer: 50%- A. 8314 J mol-1K-1
- B. 83.14 J mol-1K-2
- C. 831.4 J mol-1K-1
- D. 8.314 J mol-1K-1
Explanation: Universal gas constant is 8.314 J mol-1K-1.
Correct answer: 8.314 J mol-1K-1- A. 273.16
- B. 273.16 Q2/Q1
- C. 273.16 Q
- D. 273.16 Q1/Q2
Explanation: 𝑇 1 𝑇 2 = 𝑄1 𝑄2 The triple point of water is 0.01C or 273.16K. Inputting this value as T2 in equation above we get the answer.
Correct answer: 273.16 Q1/Q2- A. 6.21 x 10^-21 J
- B. 5 x 10^-21 J
- C. 6.21 x 10^-12 J
- D. 6 x 10^-21 J
Explanation: The mean translational kinetic energy of an ideal gas is calculated using the formula: K.E.
Correct answer: 6 x 10^-21 J- A. Isothermal
- B. Isochronic
- C. Adiabatic
- D. Isobaric
Explanation: Isochronic or isochoric processes are carried out at constant volume.
Correct answer: Isochronic- A. Δθ = Δu + Δw
- B. Δθ = Δu
- C. Δθ = Δw
- D. None
Explanation: First law of thermodynamics states " energy can neither be created nor destroyed, it can only be altered/changed into different forms".
Correct answer: Δθ = Δu + Δw- A. Isobaric process
- B. Isothermal process
- C. Adiabatic process
- D. Isochor process
Explanation: Adiabatic is a process in which heat neither enters nor leaves a system, but the temperature of the system still changes.
Correct answer: Adiabatic process- A. The efficiency of the working substance
- B. The ideal gas scale temperature
- C. The thermal conductivity at the working substance
- D. None of the above
Explanation: The ratio of heat accepted to the heat rejected by a Carnot engine gives the efficiency of the working substance.
Correct answer: The efficiency of the working substance- A. Positive
- B. Negative
- C. Zero
- D. Constant
Explanation: Work is defined as the force applied over a distance, resulting in the displacement of an object.
Correct answer: Zero- A. Total internal energy has decreased
- B. The system has lost heat
- C. Work done by the system
- D. Work done on the system
Explanation: In the first law of thermodynamics, the expression for the change in internal energy of a system can be given as:∆U = Q - WIf the…
Correct answer: Work done by the system- A. isobaric process
- B. adlabalic process
- C. isothermal process
- D. isochoric process
Explanation: The adiabatic process is performed quickly when the system is perfectly insulated from the surrounding environment.
Correct answer: adlabalic process677. Which of the following makes the motion of a perpetual motion machine a physical impossibility?
- A. fist law of thermodynamics
- B. second law of thermodynamics
- C. third law of thermodynamics
- D. None of these
Explanation: As the second law of thermodynamics states, the more energy is transformed, the more is wasted.
Correct answer: second law of thermodynamics- A. No heat enters or leaves the system
- B. The temperature remains constant
- C. All work is mechanical
- D. Energy is conserved
Explanation: The first law of thermodynamics states that energy can neither be created nor destroyed, it is converted from one form to another…
Correct answer: Energy is conserved- A. Work done
- B. Exchange of heat
- C. Change in temperature
- D. Change in internal energy
Explanation: An adiabatic process is defined as a process in which no heat transfer takes place.
Correct answer: Exchange of heat- A. The work done by the gas
- B. The work done on the gas.
- C. Change in the internal energy of the gas
- D. Zero, since the process is isothermal
Explanation: During an isothermal process, temperature and internal energy remain unchanged.
Correct answer: The work done by the gas