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JEE Main 2019 (12 Apr, Shift 2) · Heat Engines, Refrigerators & Second Law

Heat Engines, Refrigerators & Second Law question from JEE Main 2019 (12 Apr, Shift 2)

Q58JEE Main 2019 · 12 APR · SHIFT 2Medium

Heat Engines, Refrigerators & Second Law

A Carnot engine has an efficiency of 16\frac{1}{6}. When the temperature of the sink is reduced by 62ºC, its efficiency is doubled. The temperatures of the source and the sink are, respectively

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Answer: (a)

  1. T2=56T1T_2 = \frac{5}{6}T_1 and T2−62=23T1T_2 - 62 = \frac{2}{3}T_1.
  2. Subtract: T16=62⇒T1=372 K=99∘C\frac{T_1}{6} = 62 \Rightarrow T_1 = 372\text{ K} = 99^\circ\text{C}.
  3. T2=310 K=37∘CT_2 = 310\text{ K} = 37^\circ\text{C}
  4. So the answer is (a) 99∘C, 37∘C99^\circ\text{C},\ 37^\circ\text{C}.
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