An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at $1.76 \mathrm {~K}$ has an efficiency of $40.0 \%$ What is the temperature of the warm reservoir?
A)2.93 K
B)0.0500 K
C)106 K
D)0.0400 K

Question

Quizplus · Accepted Answer

The efficiency of a Carnot engine is given by $ \eta = 1 - \frac{T_c}{T_h} $. Given $\eta = 0.40$ and $T_c = 1.76 \, \text{K}$, solving for $T_h$ gives $T_h = \frac{T_c}{1 - \eta} = \frac{1.76}{0.60} = 2.93 \, \text{K}$.

An Ideal Carnot Engine Operating Between a Warm Reservoir of Unknown