JEE Main · 2020 · 04 Sep 2020 · Shift 2 · Heat & Thermodynamics

In an adiabatic process no heat is exchanged, so $\Delta Q=0$. In an isothermal process the temperature is fixed, so for an ideal gas the internal energy is unchanged and $\Delta U=0$. In an isochoric process the volume is fixed, so no work is done and $\Delta W=0$. In an isobaric process heat flows, the gas does work and its temperature changes, so $\Delta U$, $\Delta W$ and $\Delta Q$ are all non-zero. Hence the adiabatic process pairs with $\Delta Q=0$, the isothermal with $\Delta U=0$, the isochoric with $\Delta W=0$ and the isobaric with all three quantities non-zero.