Question

If the amount of heat given to a system is $35\, J$ and the amount of work done on the system is $15\, J$, then the change in internal energy of the system is

• A. -50 J
• B. 20 J
• C. 30 J
• D. 50 J

Answer 1

Answer: (D)

50 J

Answer 2

Given heat= 35 J
Work done = -15 J
Change in internal energy
$\, \, \, \, \, \Delta Q =\Delta U +W$
$\Delta U =\Delta Q -W=35 -(-15)=35+15=50 J$