Question

A thermodynamic system undergoes a process in which its internal resistance decreases by 500J. Over the same time interval, 220J of work is done on the system. Find the energy transferred from it by heat.

Answer 1

By the definition of the First Law of Thermodynamics, we have:

$$\Delta E_{int}=Q+W,$$ $$Q=\Delta E_{int}-W=-500\ J-220\ J=-720\ J.$$