The efficiency of Carnot engine is y, when it `eta` hot and cold reservoirs are maintained at temperature `T_(1)` and `T_(2)`, respectively. To increase the efficiency to `1.5 eta`, the increase in temperature `(DeltaT)` of the hot reservoir by keeping the cold one constant at `T_(2)` is 

Options

A. `(T_1 T_2)/((1- eta) (1-1.5 eta))`
B. `(0.5 T_2 eta)/((1-0.5 eta )(1- eta))`
C. `(T_1)/(1-eta)-(T_2)/(1-1.5 eta)`
D. `((1-eta)(1-1.5 eta))/(T_1 T_2)`

Answer

B