A constant-volume process is also called which term?

A constant-volume process is also called which term?

• A. Isothermal
• B. Isochoric
• C. Isobaric
• D. Isentropic

Answer: (B)

When volume is held constant, the process is iso-choric. Because the volume doesn’t change, the boundary work done by the system is zero (W = ∫P dV and dV = 0). According to the first law, Q = ΔU + W, this means all the heat added goes into changing the internal energy (since W = 0). For many gases, internal energy depends mainly on temperature, so heating at constant volume raises the temperature without any volume change. Isochoric is the standard term for this fixed-volume path. In contrast, isothermal means temperature stays the same, isobaric means pressure stays the same, and isentropic means the process is adiabatic and reversible (constant entropy).

When volume is held constant, the process is iso-choric. Because the volume doesn’t change, the boundary work done by the system is zero (W = ∫P dV and dV = 0). According to the first law, Q = ΔU + W, this means all the heat added goes into changing the internal energy (since W = 0). For many gases, internal energy depends mainly on temperature, so heating at constant volume raises the temperature without any volume change. Isochoric is the standard term for this fixed-volume path. In contrast, isothermal means temperature stays the same, isobaric means pressure stays the same, and isentropic means the process is adiabatic and reversible (constant entropy).