a heat engine uses thermal energy flowing from a heat source that is 225 k to a cold sink that is 50 k. what…

a heat engine uses thermal energy flowing from a heat source that is 225 k to a cold sink that is 50 k. what is the approximate efficiency of the heat engine? 22% 45% 78% 123%

a heat engine uses thermal energy flowing from a heat source that is 225 k to a cold sink that is 50 k. what is the approximate efficiency of the heat engine? 22% 45% 78% 123%

Answer

Explanation:

Step1: Recall efficiency formula

The efficiency $\eta$ of a heat - engine is given by $\eta = 1-\frac{T_{c}}{T_{h}}$, where $T_{h}$ is the temperature of the hot source and $T_{c}$ is the temperature of the cold sink.

Step2: Substitute values

Here, $T_{h}=225\ K$ and $T_{c} = 50\ K$. So, $\eta=1-\frac{50}{225}=1 - \frac{2}{9}=\frac{9 - 2}{9}=\frac{7}{9}\approx0.78$.

Step3: Convert to percentage

To convert the decimal to a percentage, we multiply by 100. So, $\eta\approx0.78\times100% = 78%$.

Answer:

78%