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GATE 2016 ME (ME1) – Question 59

Casting, Forming and Joining Processes · Casting: patterns, moulds, cores, solidification, riser and gating design, defects · 2 marks · Numerical answer

Heat is removed from 2 kg of molten metal at a constant 10 kW until complete solidification. The cooling curve is shown. Assuming uniform temperature throughout the metal during solidification, the latent heat of fusion is ______ kJ/kg.

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Correct answer: 49.9 to 50.1

Explanation

The constant-temperature plateau at873K lasts from10s to20s. Heat removed during this phase change is10kW·10s=100kJ. Divide by the2kg mass to obtain **50kJ/kg** latent heat. The sloping parts describe sensible cooling and must not be included.