Question

A system absorbs 900 J of heat and does work. The change in internal energy (∆U) for the process is +460 J. The work done by the system is ____________.

Options

• 440 J

• −440 J

• 1360 J

• −1360 J

Answer 1

A system absorbs 900 J of heat and does work. The change in internal energy (∆U) for the process is +460 J. The work done by the system is −440 J.

Explanation:

Q = 900 J, ∆U = +460 J

According to first law of thermodynamics,

∆U = Q + W

∴ W = ∆U − Q

= +460 J − 900 J

= −440 J