Question

Which of the following statement is true for a thermodynamical system where ∆U is the increase in internal energy and ∆W work done respectively?

• A. ∆U= -∆W in case of ideal gas
• B. ∆U = ∆W in isothermal process
• C. ∆U= -∆W in an adiabatic process
• D. ∆U = ∆W in a adiabatic process

Answer 1

The correct option is C

∆U= -∆W in an adiabatic process

In an adiabatic process no heat energy enters or leaves the system so ∆Q= 0

From first law of thermodynamics

∆Q= ∆U +∆W therefore for adiabatic process ∆U= -∆W