Q. The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is:
A) 6400 J
B) 5400 J
C) 7900 J
D) 8900 J
Explanation
[Solution from source] First law: ΔU = Q − W = 2 × 4200 − 500 = 7900 J (1 cal = 4.2 J). Adding the work instead of subtracting gives 8900 J. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.