Question

Of the following thermodynamic processes, the thermodynamic process in which internal energy of a gas remains constant is

• A. adiabatic
• B. isochoric
• C. isobaric
• D. isothermal

Answer 1

The correct option is D isothermal

An isothermal process is a change of a system, in which the temperature remains constant: $\Delta T=0$. This typically occurs when a system is in contact with an outside thermal reservoir (heat bath), and the change will occur slowly enough to allow the system to continually adjust to the temperature of the reservoir through heat exchange. In contrast, an adiabatic process is where a system exchanges no heat with its surroundings ($Q=0$). In other words, in an isothermal process, the value $\Delta T=0$and therefore $\Delta U=0$ (only for an ideal gas) but $Q\ne 0$, while in an adiabatic process, $\Delta T\ne 0$ but $Q=0$.