Question

For an isothermal process :

• A. dQ= dW
• B. dQ $=$ dU
• C. dW$=$dU
• D. dQ = dU + dW

Answer 1

The correct option is A dQ= dW

Internal energy is a function of temperature only. Therefore, in case of isothermal process, it will be constant.

From $FirstLawofThermodynamics$, $dQ=dU+dW$

and here, $dU=0$

So, $dQ=dW$