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 17 of 36
- A. 7/3
- B. 5/4
- C. 19/13
- D. 15/19
Explanation: The ratio of specific heats, γ, is given by the formula γ = Cp/Cv. For a mixture of gases, this is calculated using:γ = (n1Cp1 + n2Cp2 +…
Correct answer: 19/13- A. 60 J
- B. 30 J
- C. 45 J
- D. 120 J
Explanation: The correct answer is 120 J. In thermodynamics, when a triatomic gas expands under constant pressure, the heat supplied to the gas (Q) is…
Correct answer: 120 J- A. 3/2
- B. 23/15
- C. 19/13
- D. 4/3
Explanation: To find the effective gamma (γ) for the mixture, use the formula for the mixture of gases: γmix = (n1γ1 + n2γ2) / (n1 + n2), where n1 and…
Correct answer: 19/13- A. 15/11
- B. 17/11
- C. 13/11
- D. None
Explanation: To find the Cp/Cv (gamma, γ) for the mixture, consider the specific heat capacities for the individual gases:For a monoatomic gas, γ =…
Correct answer: 17/11- A. 75 J
- B. 100 J
- C. 150 J
- D. 125 J
Explanation: This is the following solution: (this formula must be memorised by the students because other questions may come following the same…
Correct answer: 100 J- A. 6R/19
- B. 13R/6
- C. 6R/13
- D. 19R/6
Explanation: To find the molar heat capacity of the mixture at constant pressure (Cp), we use the formula for the molar heat capacity of a…
Correct answer: 19R/6- A. 75 J
- B. 100 J
- C. 150 J
- D. 125 J
Explanation: According to the first law of thermodynamics, the change in internal energy (ΔU) is equal to the heat absorbed (Q) minus the work done…
Correct answer: 100 J- A. R
- B. 3/2R
- C. 2R
- D. 2.5R
Explanation: To find the molar specific heat at constant volume (Cv) for the mixture, we take the average of the Cv values of the monoatomic and…
Correct answer: 2R- A. 40
- B. 40.4
- C. 40.2
- D. 40.80
Explanation: Option A is correct.We know that:M=Cv/SV = 3*2/2\0.075 =40we know that CV=3/2R
Correct answer: 40- A. 28 K
- B. 20 K
- C. 15 K
- D. 10 K
Explanation: Option A is correct.Given data: For diatomic Cp/Cv=7/5Find out:∆T2 =?We know that For gas in cylinder A, Q=nCp∆T1For gas in cylinder B…
Correct answer: 28 K- A. 3/2R
- B. 7/2R
- C. 5/2R
- D. 9/2R
Explanation: The correct answer is Option C: 5/2R. This value is derived from the fact that diatomic gases have translational and rotational degrees of…
Correct answer: 5/2R- A. Entropy
- B. General gas constant
- C. Internal energy
- D. Pressure
Explanation: The correct answer is General gas constant because the unit of molar specific heat is Joules per Kelvin per mole (J/K·mol), which is the…
Correct answer: General gas constant- A. 3/2
- B. 5/3
- C. 3/5
- D. 3/4
Explanation: The correct answer is B: γ = 5/3. For a monoatomic gas, the specific heat capacity at constant volume (Cv) is 3R/2, and at constant…
Correct answer: 5/3- A. ∆U=CV∆Q
- B. ∆U=CV∆T
- C. ∆T=CV∆U
- D. ∆U=Cp∆T
Explanation: In thermodynamics, when an ideal gas is heated at constant volume, the work done on the system is zero because the volume does not change.
Correct answer: ∆U=CV∆T- A. Cp=Qp/∆T
- B. Cp=T/∆Qp
- C. Cp=∆T/Qp
- D. Cp=Qp x T
Explanation: The expression Cp = Qp / ∆T is the correct mathematical representation of molar specific heat at constant pressure.
Correct answer: Cp=Qp/∆T- A. Translatory
- B. Rotatory
- C. Vibratory
- D. None of these
Explanation: In a monoatomic gas, such as noble gases like helium, neon, argon, etc., the gas molecules consist of single atoms that are not bonded to…
Correct answer: Translatory- A. Infinity
- B. Negative
- C. Zero
- D. Remains constant
Explanation: Given the process is isothermal which means it's temperature won't increase i.e. ∆T = 0.
Correct answer: Infinity338. Which of the substances A, B or C has the highest specefic heat? The temperature vs heat graph is:
- A. A
- B. B
- C. C
- D. All have equal specefic heats
Explanation: Specific heat capacity is inversely proportional to the change in temperature.
Correct answer: C- A. γ=Cp/Cγ
- B. γ=Cγ/Cp
- C. γ=Cp- Cγ
- D. γ=CpCγ
Explanation: The equation PVγ=Constant is derived from the first law of thermodynamics for an adiabatic process.
Correct answer: γ=Cp/Cγ- A. 5/3
- B. 8/6
- C. 7/5
- D. 9/7
Explanation: The value of γ (gamma) for a gas is derived from the formula γ=1+2/f, where f is the number of degrees of freedom.
Correct answer: 9/7