A Carnot's engine is made to work between 200° C and 0° C first and then between 0° and -200° C. The ratio of efficiencies ((η2/η1)) of the engine in the two cases is :

Question

A Carnot's engine is made to work between 200° C and 0° C first and then between 0° and -200° C. The ratio of efficiencies ((η2/η1)) of the engine in the two cases is : (A) 1: 1.5 (B) 1: 1 (C) 1: 2 (D) 1.73: 1

Tardigrade Admin · Accepted Answer

n 1=1-(273/473)-1-0.57-0.43 n 2=1-(73/273)=1-0.27=0.73 ( n 2/ n 1)=(0.73/0.43)=1.73: 1

Q. A Carnot's engine is made to work between $20 0^{\circ} C$ and $0^{\circ} C$ first and then between $0^{\circ}$ and $- 20 0^{\circ} C$ . The ratio of efficiencies $(\frac{η _{2}}{η _{1}})$ of the engine in the two cases is :

$1 : 1.5$

$1 : 1$

$1 : 2$

$1.73 : 1$

$n_{1} = 1 - \frac{273}{473} - 1 - 0.57 - 0.43$
$n_{2} = 1 - \frac{73}{273} = 1 - 0.27 = 0.73$
$\frac{n _{2}}{n _{1}} = \frac{0.73}{0.43} = 1.73 : 1$

Q. A Carnot's engine is made to work between 200∘C and 0∘C first and then between 0∘ and −200∘C. The ratio of efficiencies (η1​η2​​) of the engine in the two cases is :

1:1.5

1:1

1:2

1.73:1