Thermodynamics (Physics)

0.08 kg air is heated at constant volume through 5 . The specific heat of air at constant volume is 0.17 kcal/kg C and J=4.18 joule/cal. The change in its internal energy is approximately.

1. 318 J
2. 298 J
3. 284 J
4. 142 J

Answer

(3) 284 J

Solution

Constant volume W=0 U=Q=mcv T (first law)

U=0.08 0.17 5=0.068 kcal=68 cal

U=68 4.18 284 J

Answer: (3)