JEE Mains · Physics · STD 11 - 11. thermodynamics
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.
- A same as the \(1^{\text {st }}\) case
- B always greater than the \(1^{\text {st }}\) case
- C always less than the \(1^{\text {st }}\) case
- D may increase or decrease with respect to the \(1^{\text {st }}\) case
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 : \(\eta_{\text {net }}=\eta_{1}+\eta_{2}-\eta_{1} \eta_{2}\) \(\eta_{1}=1-\frac{200}{300}=\frac{1}{3}\) \(\eta_{2}=1-\frac{100}{200}=\frac{1}{2}\)…
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