Question

During what kind of process is there no change in internal energy?

• A. adiabatic
• B. isothermal
• C. isobaric
• D. cyclic (one cycle)
• E. Two of the answers are correct.

Answer 1

The correct option is E Two of the answers are correct.

Isothermal process : $T=constant$ i.e $\Delta T=0$ K

Change in internal energy $\Delta U=n{C}_v\left(\Delta T\right)=0$ J

Thus internal energy remains constant in an isothermal process.

As internal energy is a state function, thus change in internal energy is also zero in one cycle of a cyclic process.

Hence option E is correct.