Question

If a heat engine absorbs 2 kJ heat from a heat source and releases 1.5 kJ heat into cold reservoir, then its efficiency is ............
(A) 25%
(B) 50%
(C) 75%
(D) 0.5%

Answer 1

Answer:

(C)75%

Explanation:

Efficiency=(Output/Input)×100%

Output=1500J

Input=2000J

(1500/2000)×100%=75%

Answer 2

Answer:

Correct option: (A) 25%

Explanation:

Heat absorbed from heat source = 2 KJ = Q1

Heat released = 1.5 KJ = Q2

n=1 - (Q2/Q1)

= 1- (1.5/2.0)

n = (1/4)

i.e. % efficiency = (1/4) x 100 = 25%