1. A steam engine converts 150 kg of water completely to steam. The process involves transfer of 4 x 10^8 J as heat. If steam escaping through the safety valve does 2 x 10^8 J of work against outside atmosphere, the net change in the internal energy is:

Question

1. A steam engine converts 150 kg of water completely to steam. The process involves transfer of 4 x 10^8 J as heat. If steam escaping through the safety valve does 2 x 10^8 J of work against outside atmosphere, the net change in the internal energy is: 
a. 2 J 
b. 2 x 108 J 
c. 6 J 
d. 6 x 108 J

MathMate · Answer

Work to transformed water to steam = 4*10^8 J Work to overcome safety valve=2*10^8 J. Both work are added to the internal energy.