A Carnot's engine is made to work between 200° C and 0° C first and then between 0° C and -200° C. The ratio of efficiencies of the engine is the two cases is

Question

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

Tardigrade Admin · Accepted Answer

η=1-(T2/T1) ∴ η1=1-(273/473)=(200/473) η1=1-(73/273)=(200/273) ∴ η1/η2=(273/473)=(1/1.73)

Q. A Carnot's engine is made to work between $20 0^{\circ} C$ and $0^{\circ} C$ first and then between $0^{\circ} C$ and $- 20 0^{\circ} C$ . The ratio of efficiencies of the engine is the two cases is

1.73 : 1

1 : 1.73

1 : 1

1 : 2

$η = 1 - \frac{T _{2}}{T _{1}}$
$∴ η_{1} = 1 - \frac{273}{473} = \frac{200}{473}$
$η_{1} = 1 - \frac{73}{273} = \frac{200}{273}$
$∴ η_{1} / η_{2} = \frac{273}{473} = \frac{1}{1.73}$

Q. A Carnot's engine is made to work between 200∘C and 0∘C first and then between 0∘C and −200∘C. The ratio of efficiencies of the engine is the two cases is