Two Carnot engines A and B are operated in series. Engine A receives heat from a reservoir at 600 K and rejects heat to a reservoir at temperature T . Engine B receives heat rejected by engine A and in turn rejects it to a reservoir at 100 K . If the efficiencies of the two engines A and B are represented by $\eta _ { A }$ and $\eta _ { B }$ respectively, then what is the value of $\frac { \eta _ { \mathrm { A } } } { \eta _ { \mathrm { B } } }$ (1) $\frac { 12 } { 7 }$ (2) $\frac { 12 } { 5 }$ (3) $\frac { 5 } { 12 }$ (4) $\frac { 7 } { 12 }$
Two Carnot engines A and B are operated in series. Engine A receives heat from a reservoir at 600 K and rejects heat to a reservoir at temperature T . Engine B receives heat rejected by engine A and in turn rejects it to a reservoir at 100 K . If the efficiencies of the two engines A and B are represented by $\eta _ { A }$ and $\eta _ { B }$ respectively, then what is the value of $\frac { \eta _ { \mathrm { A } } } { \eta _ { \mathrm { B } } }$\\
(1) $\frac { 12 } { 7 }$\\
(2) $\frac { 12 } { 5 }$\\
(3) $\frac { 5 } { 12 }$\\
(4) $\frac { 7 } { 12 }$