A Carnot's engine is made to work between `200^(@)C` and `0^(@)C` first and then between `0^(@)C` and `-200^(@)C`. The ratio of efficiencies of the engine in the two cases is

Options

A. `1:15`
B. `1:1`
C. `1:2`
D. `1.73:1`

Answer

D

Explanation

Case 1: `T_(2)=0^(2)C=273K`
`T_(1)=200^(2)C=473K`
`eta_(1)=1-273/473=200/473`
Case 2: `T_(2)^(.)=-200^(@)C=73K`
`T_(1)^(.)=0^(@)C=273K`
`eta_(2)=1-73/273=eta_(2)=200/273`
`((eta_(2))/(eta_(1))=473/273=1.73/1)`