Answer to Question #148679 in Physics for Kingsley chinedu

Question

A Carnot heat engine is operated between two heat reservoirs at temperature 400K and 300K. If the engine receives 200 Caloriesfrom the 400K reservoir, what is the thermal efficiency of the engine

Answer 1

According to the Carnot's theorem, the thermal efficiency efficiency of a Carnot heat engine is the ratio of the temperature difference between the reservoirs and the temperature of the hot reservoir, expressed in the equation (https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodynamics)):

$$\eta =\dfrac{T_2-T_1}{T_2} = 1-\dfrac{T_1}{T_2}$$

where, in our case, $T_1 = 300K$ and $T_2 = 400K$. Thus, obtain:

$$\eta = 1-\dfrac{300K}{400K} = 0.25$$

Answer. 0.25.