JEE Mains · Physics · STD 11 - Thermodynamics
- JEE Mains 2022
- Medium
- MCQ
In \(1^{\text {st }}\) case, Carnot engine operates between temperatures \(300\,K\) and \(100\,K\). In \(2^{\text {nd }}\) case, as shown in the figure, a combination of two engines is used. The efficiency of this combination (in \(2^{\text {ad }}\) case) will be.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) same as the \(1^{\text {st }}\) case
Step-by-step Solution
Detailed explanation
First case : \(\eta=1-\frac{100}{300}=\frac{2}{3}\)
Second case : \(\eta_{\text {net }}=\eta_{1}+\eta_{2}-\eta_{1} \eta_{2}\)
\(\eta_{1}=1-\frac{200}{300}=\frac{1}{3}\)
\(\eta_{2}=1-\frac{100}{200}=\frac{1}{2}\)
\(\eta_{\text {net }}=\frac{1}{3}+\frac{1}{2}-\frac{1}{6}=\frac{2}{3}\)
\(\eta\) (first case) \(=\eta\) (second case)
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