Q.

A Carnot engine operating between two reservoirs has efficiency 13. When the temperature of the cold reservoir is raised by x, its efficiency decreases to 16. The value of x, if the temperature of the hot reservoir is 99°C, will be                  [2023]

1 16.5 K  
2 33 K  
3 66 K  
4 62 K  

Ans.

(4)

TH=99°C=99+273=372 K

1-THTC=13

TCTH=23    ...(1)

 TC=23×372=2×124=248 K

      1-TC+XTH=16

 56=248+X372

      248+X=5×62

 X=310-248=62 K