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NDA 2024 GAT · General Knowledge · Heat and Thermal Physics · medium

The heat needed to melt 500 g of ice at 0 °C completely into water at 0 °C is (latent heat of fusion of ice = 336 J/g)

Single correct option

The heat needed to melt 500 g of ice at 0 °C completely into water at 0 °C is (latent heat of fusion of ice = 336 J/g)
  1. A. 336000 J
  2. B. 16800 J
  3. C. 84000 J
  4. D. 168000 J
Show answer and solution

Answer: (D) 168000 J

Q = mL = 500 × 336 = 168000 J. The temperature stays at 0 °C during melting, so the heat is used only to break the bonds between the molecules, and no mcΔT term is needed. The trap is to take 1 kg or to forget the mass.
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Original question written in the NDA 2024 GAT pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake