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JEE Main 2021 (25 Jul, Shift 1) · Calorimetry, Latent Heat & Mechanical Equivalent of Heat

Calorimetry, Latent Heat & Mechanical Equivalent of Heat question from JEE Main 2021 (25 Jul, Shift 1)

Q28JEE Main 2021 · 25 JUL · SHIFT 1Medium

Calorimetry, Latent Heat & Mechanical Equivalent of Heat

Two different metal bodies A and B of equal mass are heated at a uniform rate under similar conditions. The variation of temperature of the bodies is graphically represented as shown in the figure. The ratio of specific heat capacities is:

Figure

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Answer: (b)

  1. Same heating rate and mass: P=mcdTdt⇒c∝1slopeP = mc\dfrac{dT}{dt} \Rightarrow c \propto \dfrac{1}{\text{slope}}.
  2. Slope of A =1203=40∘C/s= \dfrac{120}{3} = 40^{\circ}\text{C/s}; slope of B =906=15∘C/s= \dfrac{90}{6} = 15^{\circ}\text{C/s}.
  3. cAcB=1540=38\dfrac{c_A}{c_B} = \dfrac{15}{40} = \dfrac{3}{8}
  4. So the answer is (b) 38\dfrac{3}{8}.
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