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JAMB Physics 2012 Question 24

Question 24

Change of State and Vapours

The quantity of heat energy required to melt completely 1 kg of ice at −30°C is [latent heat of fusion = 3.5 × 105 Jkg−1, specific heat capacity of ice = 2.1 × 103 Jkg−1K−1]

  1. A.4.13 × 106J
  2. B.4.13 × 105J
  3. C.3.56 × 104J
  4. D.3.56 × 102J
Show the answer and explanation

Answer: B (4.13 × 105J)

Explanation

Warm the ice to 0°C: 1 × 2100 × 30 = 63 000 J. Melt it: 1 × 3.5 × 105 = 350 000 J. Total = 413 000 J = 4.13 × 105 J.