An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62⁰C, its efficiency is doubled. Temperature of the source is

Options

(a) 37⁰C
(b) 62⁰C
(c) 99⁰C
(d) 124⁰C

Correct Answer:

99⁰C

Explanation:

Since efficiency of engine is ? = 1 – T₂ / T₁
According to the problem, 1/6 = 1 – T₂ / T₁ ……(1)
When the temperature of the sink is reudced by 62⁰C, its efficiency is doubled
2 (1/6) = 1 – T₂ – 62 / T₁ ……..(2)Solving (1) and (2) T₂ = 372 K
T₁ = 99⁰C = Temperature of source.