Question

"The work done on an ideal gas system in an isothermal process is -400 J. What is the change in internal (thermal) energy of the gas?"

Answer 1

zero

Step-by-step explanation:

Work done = - 400 J

In an isothermal process, the temperature remains constant. So, according to the first law of thermodynamics

dQ = dU + dW

As the temperature remains constant and the change in internal energy is the function of change in temperature, here change is temperature is zero so the change in internal energy is also zero.