. In a thermodynamic process pressure of a fixed mass of a gas


is changed in such a manner that the gas releases 20 J of heat and 8 J of work is done on the gas

if the initial internal energy of the gas was 30 J. The final internal energy wilI be:

A: 26 J

B: 15 J

C: 18 J

D: 9 J

 

Best Answer

Answer:

Explanation:

The heat dQ=-20J dW=-8J U1=30J

Accroding to thermodynamic law

dQ=dU+dW

dU=dQ-dW

dU=-20-(-8)

dU=-12j

So internal energy will be

U2=U1+dU

U2=30-12 = 18 Joule

Final Answer:

The final internal energy wilI be 18 joule .The correct option is (C). 

 

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