Question

How much Work will be done if 420 J of Heat has been added to the Isothermal Process.

Answer 1

Given:

$Q=\rm 420\: J$

$T=\rm const$

The first law of thermodynamics says

$$Q=\Delta U+W$$

For the isothermal processes

$$\Delta U=0$$

Thus, the work done

$$W=Q=\rm 420\: J$$