Question

An ideal gas is enclosed in a cubical container. The container has a hole in its top face. During the process of heating, at any instant the internal energy of the gas enclosed in the container is U, (Neglect the thermal expansion of the container) then the value of U

• A. decreases continuously
• B. remains constant
• C. increases continuously
• D. first decreases, then increases

Answer 1

The correct option is B remains constant

Internal energy, $U=\frac{f}{2}PV$

P and V both are constants and as we know that degrees of freedom is constant for a particular case, which implies that U will remain constant.