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MHT CET 2023 (10 May, Shift 1) · Heat Engines, Refrigerators & Second Law

Heat Engines, Refrigerators & Second Law question from MHT CET 2023 (10 May, Shift 1)

Q24MHT CET 2023 · 10 MAY · SHIFT 1Medium

Heat Engines, Refrigerators & Second Law

A Carnot engine with efficiency 50%50\% takes heat from a source at 600 K600\text{ K}. To increase the efficiency to 70%70\%, keeping the temperature of the sink same, the new temperature of the source will be

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Answer: (b)

  1. T2=(1−0.5)(600)=300 KT_2 = (1 - 0.5)(600) = 300\text{ K}
  2. For η=0.7\eta = 0.7: T1′=T21−0.7=3000.3=1000 KT_1' = \frac{T_2}{1 - 0.7} = \frac{300}{0.3} = 1000\text{ K}
  3. So the answer is (b) 1000 K1000\text{ K}.
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