Question

In a process, 701 J of heat is absorbed by a system and 394 J of work is done by the system. What is the change in internal energy for the process? 

Answer 1

According to the first law of thermodynamics, 

∆U = q + W (i) 

Where, 

∆U = change in internal energy for a process 

q = heat 

W = work Given, 

q = + 701 J (Since heat is absorbed) 

W = –394 J (Since work is done by the system) Substituting the values in expression (i), we get 

∆U = 701 J + (–394 J) 

∆U = 307 J 

Hence, the change in internal energy for the given process is 307 J.