THERMODYNAMICS MCQ SET 1
Q1. In a reversible process, entropy:
A) Increases
B) Decreases
C) Remains constant
D) Becomes zero
ย Answer: C) Remains constant
Explanation: For reversible processes, there is no entropy generation.
Q2. Specific heat at constant pressure is always:
A) Less than Cp
B) Greater than Cv
C) Equal to Cv
D) Zero
Answer: B) Greater than Cv
Explanation: At constant pressure, part of the heat is used to do work, so Cp > Cv.
Q3. The ratio of Cp/Cv is called:
A) Entropy
B) Specific heat ratio (ฮณ)
C) Thermal efficiency
D) Temperature ratio
ย Answer: B) Specific heat ratio (ฮณ)
Explanation: The ratio of specific heats is denoted by ฮณ = Cp/Cv.
Q4. Work done in an isochoric process is:
A) Maximum
B) Minimum
C) Zero
D) Constant
Explanation: In a constant volume process, no boundary work is done.
Q5. The internal energy of an ideal gas depends only on:
A) Volume
B) Pressure
C) Temperature
D) Density
Answer: C) Temperature
Explanation: Internal energy for an ideal gas is a function of temperature only.
Q6. One kilocalorie equals:
A) 4.184 kJ
B) 418.4 kJ
C) 41.84 J
D) 0.4184 kJ
Answer: A) 4.184 kJ
Explanation: 1 kcal = 4.184 kilojoules.
Q7. The work done in a reversible adiabatic process is:
A) Maximum
B) Minimum
C) Zero
D) Negative
Answer: A) Maximum
Explanation: For a given change, adiabatic reversible process gives maximum work.
Q8. Which law of thermodynamics introduces the concept of entropy?
A) Zeroth law
B) First law
C) Second law
D) Third law
Answer: C) Second law
Explanation: The second law introduces entropy and direction of energy flow.
Q9. The efficiency of a Carnot engine is:
A) 1 โ (T2/T1)
B) 1 + (T2/T1)
C) (T2/T1)
D) (T1/T2)
Answer: A) 1 โ (T2/T1)
Explanation: Carnot efficiency depends on temperature ratio between sink (T2) and source (T1).
Q10. The Kelvin-Planck statement is related to:
A) First law
B) Second law
C) Third law
D) Zeroth law
Answer: B) Second law
Explanation: It states that no device can convert all heat into work in a cyclic process.
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