question_answer

A gas is compressed from a volume of \[2{{m}^{3}}\] to a volume of \[1{{m}^{3}}\] at a constant pressure of \[100N/{{m}^{2}}.\] Then it is heated at constant volume by supplying 150 J of energy. As a result, the internal energy of the gas:   [JEE ONLINE 19-04-2014]

A)  increases by 250 J

B)       decreases by 250 J

C)  increases by 50 J

D)       decreases by 50 J

Correct Answer: A

Solution :

[a]

As we know, (Ist law of thermodynamics)

or

Thus the internal energy of the gas increases by 250 J