Question

Internal energy of a gas remains unchanged in:
I. an isothermal process
II. an adiabatic process
III. a reversible process
IV. a cyclic process

• A. I and IV
• B. I, III and IV
• C. III and IV
• D. II and III

Hint:

Internal energy depends only on temperature and state.

Answer 1

The Correct Option is A

Concept: Internal energy depends only on temperature.

Step 1: Isothermal process.
Temperature remains constant \(\Rightarrow\) internal energy unchanged.

Step 2: Adiabatic process.
Temperature changes \(\Rightarrow\) internal energy changes.

Step 3: Cyclic process.
System returns to initial state \(\Rightarrow\) net change in internal energy = 0.

Step 4: Conclusion.
Correct statements: I and IV.