Efficiencies of a carnot engine η=1−Tsource Tsink $\begin{aligned}
\Rightarrow & \eta_1=1-\frac{373 \mathrm{K}}{473 \mathrm{K}}=\frac{100}{473} \
& \eta_2=1-\frac{273 \mathrm{K}}{373 \mathrm{K}}=\frac{100}{373} \
& \eta_{12}=1-\frac{273 \mathrm{K}}{473 \mathrm{K}}=\frac{100}{473} \
& \eta_{12}-\eta_1=\frac{200}{473}-\frac{100}{473}=\frac{100}{473} < \frac{100}{373} \
\Rightarrow & \eta_{12}-\eta_1 < \eta_2 \
\text { or } & \eta_{12} < \eta_1+\eta_2
\end{aligned}$
A Carnot engine ( E) is working between two temperatures 473 K and 273 K . In a new system two engines - engine E_1 works between 473 K to 373 K and…
JEE Main 2025 — Physics Thermodynamics
A Carnot engine (E) is working between two temperatures 473 K and 273 K . In a new system two engines - engine E1 works between 473 K to 373 K and engine E2 works between 373 K to 273 K . If η12,η1 and η2 are the efficiencies of the engines E,E1 and E2, respectively, then
Held on 28 Jan 2025 · Verified 6 Jul 2026.
Options
- A
η12=η1η2
- B
η12≥η1+η2
- C
η12=η1+η2
- D
η12<η1+η2
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