What happens to the internal energy of a gas during isothermal expansion?

Question

What happens to the internal energy of a gas during isothermal expansion? (A) Internal energy will decrease (B) Internal energy: will increase (C) Internal energy will become zero (D) Internal energy will remain same

Tardigrade Admin · Accepted Answer

For a process to be isothermal, any heat flow into or out of the system must occur slowly enough, so that thermal equilibrium is maintained. Hence, in a isothermal process, temperature during the whole process does not change i.e., internal energy which is a function of temperature remains same throughout the process.

Q. What happens to the internal energy of a gas during isothermal expansion?

Internal energy will decrease

Internal energy: will increase

Internal energy will become zero

Internal energy will remain same