The temperature -entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is

Options

A. `1//3`
B. 2//3`
C. `1//2`
D. `1//4`

Answer

C

Explanation

`Q_(1)=T_(0)S_(0)+1/2 T_(0)S_(0)= 3/2 T_(0)S_(0)`


`Q_(2) = T_(0)S_(0)` and `Q_(3) =0`
`eta = W/(Q_1) = (Q_1-Q_2)/(Q_1)`
`=1-(Q_2)/(Q_1)=1-2/3=1/3`.