Question

The thermodynamic process in which the change in internal energy of the system becomes zero is

• A. Adiabatic process
• B. Isothermal process
• C. Isobaric process
• D. Isochoric process

Hint:

For an ideal gas, internal energy depends only on temperature, so $\Delta U = 0$ in an isothermal process where temperature is constant.

Answer 1

The Correct Option is B

The internal energy of an ideal gas is \( U = nC_v T \), which depends only on temperature. In an isothermal process, the temperature \( T \) remains constant (\( \Delta T = 0 \)), so the change in internal energy \( \Delta U = nC_v \Delta T = 0 \).

- Adiabatic: \( \Delta U = -W \) (work done changes internal energy).
- Isobaric: \( \Delta U \neq 0 \) (temperature changes).
- Isochoric: \( \Delta U = Q \) (heat changes internal energy).

Thus, only in an isothermal process is \( \Delta U = 0 \).