Question

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

• A. 1.73 : 1
• B. 01:01.7
• C. 1:01
• D. 1:02

Answer 1

Answer: (B)

01:01.7

Answer 2

$\eta=1-\frac{T_2}{T_1}$
$\therefore\,\eta_1=1-\frac{273}{473}=\frac{200}{473}$
$\eta_1=1-\frac{73}{273}=\frac{200}{273}$
$\therefore\,\eta_1/\eta_2=\frac{273}{473}=\frac{1}{1.73}$