Three hundred joules of heat are added to a system. the system uses 140 joules to do work.
by how much did the internal energy of the system change?
a 140 j
b 160 j
c 240 j
d 440 j

Change in internal energy of the system is 160 J.

Explanation:

It is given that,

Heat added to the system, Q = 300 J

Work done by the system, W = 140 J

We need to find the change in internal energy of the system. It can be calculated using the first law of thermodynamics. Let is the change in internal energy of the system.

So, the change in internal energy of the system is 160 Joules. Hence, the correct option is (b) "160 J".