Thermodynamics Question 113
Question: Find the change in internal energy of the system when a system absorbs 2 kilocalorie of heat and at the same time does 500 joule of work
[EAMCET 1984]
Options:
A) 7900 J
B) 8200 J
C) 5600 J
D) 6400 J
Show Answer
Answer:
Correct Answer: A
Solution:
$ \Delta Q=2kcal=2\times 10^{3}\times 4.2J $
$ =8400J $ and $ \Delta W=500J. $
Hence from $ \Delta Q=\Delta U+\Delta W, $
$ \Delta W=\Delta Q-\Delta U $ = 8400 - 500 = 7900 J
