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 36 of 36
- A. 227K
- B. 300K
- C. 370K
- D. 390K
Explanation: Rearranging the ideal gas law gives T = PV/nR = (2.50 x 10^5 x 1.00 x 10^-2)/(1 x 8.314) = 2500/8.314 = 300 K.
Correct answer: 300K- A. 361K
- B. 298K
- C. 273K
- D. 250K
Explanation: For a fixed mass of gas the thermometer relation is T = T_triple x (PV)/(Pf Vf), with the triple point of water at 273.16 K.
Correct answer: 361K- A. 20X
- B. 300X
- C. 200X
- D. 2X
Explanation: Average kinetic energy is proportional to absolute temperature, not to Celsius temperature, so convert first: 27 C is 300 K and 327 C is…
Correct answer: 2X- A. ⅓ mean K.E/volume
- B. ½ Mean K.E/volume
- C. ⅔ mean K.E/volume
- D. Mean K.E/volume
Explanation: Starting from PV = (1/3)Nm<v^2> and writing the mean kinetic energy per molecule as (1/2)m<v^2>, the pressure becomes P = (2/3) x (total…
Correct answer: ⅔ mean K.E/volume- A. double
- B. one fourth
- C. four times
- D. half
Explanation: Density is mass divided by volume and the mass of gas is fixed, so doubling the volume at constant temperature halves the density.
Correct answer: half- A. decreases
- B. remains constant
- C. is zero
- D. increase
Explanation: The second law of thermodynamics says the entropy of an isolated system increases in every irreversible process.
Correct answer: increase- A. Pressure, but not volume or temperature
- B. Temperature, but not pressure or volume
- C. Volume, but not pressure or temperature
- D. Pressure and temperature, but not volume
Explanation: For an ideal gas the internal energy is purely the kinetic energy of its molecules, and that depends only on absolute temperature.
Correct answer: Temperature, but not pressure or volume- A. Half
- B. Double
- C. 4 times
- D. Unchanged
Explanation: From PV = nRT, the volume is V = nRT/P. Doubling the absolute temperature multiplies the volume by 2 and quadrupling the pressure divides…
Correct answer: Half- A. A gas is cooled
- B. A plate is shattered
- C. An egg is scrambled
- D. A drop of dye diffuses in a cup of water
Explanation: Cooling a gas removes energy and reduces the number of microstates available to it, so its entropy falls.
Correct answer: A gas is cooled- A. I only
- B. II only
- C. III only
- D. I & II only
- E. I, II & III
Explanation: All three statements are standard postulates of the kinetic theory: a finite volume contains a very large number of molecules, molecular…
Correct answer: I, II & III- A. P decreases by a factor of 16
- B. P decreases by a factor of 4
- C. P decreases by a factor of 2
- D. P increases by a factor of 4
- E. P increases by a factor of 16
Explanation: From PV = nRT, the pressure is P = nRT/V. Multiplying the temperature by 2 doubles the pressure while multiplying the volume by 8 divides…
Correct answer: P decreases by a factor of 4- A. I only
- B. III only
- C. I and II only
- D. I and III only
- E. II and III only
Explanation: At constant pressure Charles's law makes volume proportional to absolute temperature, so statement I holds.
Correct answer: I and III only- A. 359.4 °F
- B. -459.4 °F
- C. 100 °F
- D. -259.4 °F
Explanation: Absolute zero is -273.15 C. Converting with F = (9/5)C + 32 gives (9/5)(-273.15) + 32 = -491.67 + 32 = -459.67 F, which this paper rounds…
Correct answer: -459.4 °F- A. 0K
- B. -273.15 C
- C. -459.4 F
- D. All of these
Explanation: Absolute zero is one temperature written on three scales: 0 K, -273.15 C and about -459.67 F.
Correct answer: All of these