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

From η=1−T2 T1,⇒T2 T1=1−η=1−16=56… (i) In 2nd case : T2−62 T1=1−η'=1−26=23….. (ii)Using (i),T2−62=23 T1=23×65 T2=45 T2⇒15 T2=62,⇒T2=310 K=310−273=37°C∴T1=65 T2=65×310=372 K=372−273=99°C