The thermal efficiency (\(\eta\)) of a Carnot engine operating between a hot reservoir at absolute temperature \(T_H\) and a cold reservoir at absolute temperature \(T_C\) is given by:
$$ \eta_{Carnot} = 1 - \frac{T_C}{T_H} $$
Given:
Hot reservoir temperature \(T_H = 500\) K
Cold reservoir temperature \(T_C = 300\) K
Substitute the values:
$$ \eta = 1 - \frac{300 \, \text{K}}{500 \, \text{K}} $$
$$ \eta = 1 - \frac{3}{5} = 1 - 0.
6 = 0.
4 $$
To express the efficiency as a percentage, multiply by 100%:
$$ \text{Efficiency} = 0.
4 \times 100\% = 40\% $$
The efficiency of the Carnot engine is 40%.