An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62°C, its efficiency is doubled. Temperature of the source is :

99°C

Since efficiency of engine is : \(\eta = 1 - \frac{T_2}{T_1}\)

When the temperature of the sink is reduced by 62°C, its efficiency is doubled : \(2\eta = 1 - \frac{T_2-62}{T_1}\)

According to ques : \(\eta = \frac{1}{6}\)

⇒ T₂ = 372 K ; T₁ = 99°C = Temperature of source