An engine has an efficiency of `(1)/(6)`. When the temperature of sink is reduced by `62^(@)C`, its efficiency id doubled. Temperature of the source is

Options

A. `62^(@)C,124^(@)C`
B. `99^(@)C,37^(@)C`
C. `124^(@)C,62^(@)C`
D. `37^(@)C,99^(@)C`

Answer

B

Explanation

`eta=1-(T_(2))/(T_(1))`
`1/6=1-(T_(2))/(T_(1))rArr(T_(2))/(T_(1))=5/6`
Finally, efficiency is doubled on reducing sink temperature by `62^(@)`
`rArr2/6=1-(T_(2)-62)/(T_(1))=4/6rArr(T_(2))/(T_(1))-62/(T_(1))=4/6`
`T_(1)=372K=99^(@)C,T_(2)=310K=37^(@)C`