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 11 of 36
- A. Q= ∆U+W
- B. ΔU= Q-W
- C. W= Q+ ∆U
- D. Q= W
- E. B and A
Explanation: The first law of thermodynamics is given as ΔU = Q - W or Q = ΔU + W, where ΔU is the change in internal energy of a system, Q is the net…
Correct answer: B and A- A. Heat
- B. Work
- C. Momentum
- D. Energy
Explanation: The correct statement is D. Energy. The first law of thermodynamics concerns the conservation of energy, stating that the total energy of…
Correct answer: Energy- A. 25 J
- B. 100 J
- C. 150 J
- D. 250 J
Explanation: The first law of thermodynamics states that the change in internal energy (ΔU) of a system is equal to the heat added to the system (Q)…
Correct answer: 150 J- A. +1000 J
- B. +5000 J
- C. 0J
- D. +500 J
Explanation: W = PΔVΔV = V2 - V1ΔV = 50 * 10-3 - 25 * 10-3 ΔV = 25 * 10-3 W = 20,000 * 25 * 10-3 W = 500 JCalculate the change in internal energy.
Correct answer: +500 J- A. ΔU=Q+W
- B. ΔU=Q-W
- C. ΔU=Q*W
- D. ΔU=Q/W
Explanation: The first law of thermodynamics, also known as the law of energy conservation, states that the change in internal energy (ΔU) of a closed…
Correct answer: ΔU=Q-W- A. decrease
- B. increase
- C. become zero
- D. remain constant
Explanation: During an isothermal process, the temperature of the system remains constant.
Correct answer: remain constant- A. Work can never be converted into heat.
- B. Work can be converted completely into heat.
- C. Both heat and work are interconvertible.
- D. Heat can never be converted into work.
- E. Heat can be converted completely into work.
Explanation: Yes, heat and work are interconvertible forms of energy. In thermodynamics, they can be transformed into each other.
Correct answer: Both heat and work are interconvertible.- A. Isochoric
- B. Isobaric
- C. Adiabatic
- D. Isotropic
- E. Isothermal
Explanation: The process in which all the supplied heat is converted into work is called a reversible isothermal process.
Correct answer: Isothermal- A. Remains constant during the initial phase of the process
- B. Remains constant throughout the process
- C. Alters throughout the process
- D. Increases throughout the process
Explanation: In an isothermal process, the temperature of the system remains constant.
Correct answer: Remains constant throughout the process- A. 1
- B. 0
- C. -1
- D. 2
Explanation: In an adiabatic process, the value of heat energy (\(Q\)) is zero. This is because, by definition, an adiabatic process is one in which no…
Correct answer: 0- A. Adiabatic condition
- B. Isobaric condition
- C. Isochoric condition
- D. Isothermal condition
Explanation: The isothermal condition is the best for performing maximum work, particularly in reversible processes, because the system can exchange…
Correct answer: Isothermal condition- A. becomes maximum
- B. becomes minimum
- C. becomes zero
- D. remains constant
Explanation: In an isothermal process change in energy ΔU becomes zero.
Correct answer: becomes zero- A. Adiabatic condition
- B. Isochoric condition
- C. Isobaric condition
- D. Isothermal condition
Explanation: In an isochoric process, the volume remains constant. Since work is defined as W=PΔV, where ΔV=0 means no work is performed.
Correct answer: Isochoric condition- A. The temperature decreases
- B. The temperature increases
- C. The temperature remains constant
- D. Temperature increases first then decreases
Explanation: During an adiabatic process, when the volume of a gas decreases, its temperature increases due to the work done on the gas, which raises…
Correct answer: The temperature increases- A. Absorbs heat
- B. Releases heat
- C. Neither absorbs nor releases heat
- D. None of the given options
Explanation: For isothermal expansion of an ideal gas, work is done by the system, and to keep the temperature constant, heat must be absorbed.
Correct answer: Absorbs heat- A. Isothermal steps only
- B. Adiabatic steps only
- C. Both adiabatic and isothermal steps
- D. Neither adiabatic nor isothermal
Explanation: The Carnot cycle consists of two isothermal and two adiabatic processes.These steps are essential for its maximum efficiency.Therefore…
Correct answer: Both adiabatic and isothermal steps- A. Increases
- B. Decreases
- C. Remains the same
- D. Decreases by 0.1 J
Explanation: Since the heat added equals the work done, the internal energy does not change.Therefore, this option is correct.
Correct answer: Remains the same- A. 7900 J
- B. 8200 J
- C. 5600 J
- D. 6400 J
Explanation: Correct. Applying the first law of thermodynamics: ΔU = Q - W Q = 2 kcal = 2000 cal = 2000 × 4.186 J = 8372 J W = 500 J ΔU = 8372 J - 500…
Correct answer: 7900 J- A. 150 J
- B. 70 J
- C. 110 J
- D. 40 J
Explanation: Correct. Applying the first law of thermodynamics: ΔU = Q - W W = Q - ΔU Q = 110 J ΔU = 40 J W = 110 J - 40 J = 70 J
Correct answer: 70 J- A. 166 cal
- B. 333 cal
- C. 500 cal
- D. 400 cal
Explanation: Correct. Using the first law of thermodynamics: ΔU = Q - W Q = ΔU + W Q = 167 cal + 333 cal = 500 cal
Correct answer: 500 cal