Question

A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by 62ŗC, the efficiency of the engine is doubled. The temperatures of the source and sink are-

• A. 80⁰C, 37⁰C
• B. 95⁰C, 28⁰C
• C. 90⁰C, 37⁰C
• D. 99⁰C, 37⁰C

Answer 1

Answer: (D)

99⁰C, 37⁰C

Answer 2

h = $\frac{1}{6}$ = 1 – $\frac{T_{2}}{T_{1}}$

h' = $\frac{2}{6} = \frac{1}{3}$ = 1 – $\frac{T_{2}'}{T_{1}}$ = 1 – $\frac{\left\lbrack T_{2} - 62 \right\rbrack}{T_{1}}$

h' = h + $\frac{62}{T_{1}}$and h' = 2h

T₁ = 327 K = 99⁰C, T₂ = 310 K = 37⁰C