A heat engine has an efficiency of 1/6. When the temperature of sink is reduced by 62 ° C, its efficiency gets doubled. The temperature of the source is: (a) 124 ° C (b) 37 ° C (c) 62 ° C (d) 99 ° C

Answer: (d). T₂ = 5/6T₁ and, with doubled efficiency 1/3, T₂ - 62 = 2/3T₁. Subtract: T₁/6 = 62 ⇒ T₁ = 372 K. T₁ = 372 - 273 = 99 So the answer is (d) 99.

A heat engine has an efficiency of 1/6. When the temperature of sink… | JEE Main 2021 (25 Jul, Shift 2)

Q45JEE Main 2021 · 25 JUL · SHIFT 2Medium

Heat Engines, Refrigerators & Second Law

A heat engine has an efficiency of $\frac{1}{6}$ . When the temperature of sink is reduced by 62 $^\circ$ C, its efficiency gets doubled. The temperature of the source is:

Show answer and solution

Answer: (d)

$T_2 = \frac{5}{6}T_1$ and, with doubled efficiency $\frac{1}{3}$ , $T_2 - 62 = \frac{2}{3}T_1$ .
Subtract: $\frac{T_1}{6} = 62 \Rightarrow T_1 = 372\text{ K}$ .
$T_1 = 372 - 273 = 99^\circ\text{C}$
So the answer is (d) $99^\circ\text{C}$ .

Report a mistake

Heat Engines, Refrigerators & Second Law question from JEE Main 2021 (25 Jul, Shift 2)

More questions on Heat Engines, Refrigerators & Second Law