2 kg ice at − 20°C is mixed with 5 kg water at 20°C. Then final amount of water in the mixture would be; Given specific heat of ice = 0.5cal/g°C, specific heat of water = 1 cal/g°C, Latent heat of fusion of ice = 80 cal/g.
Physics · Thermodynamics
JEE Advanced

Question

2 kg ice at − 20°C is mixed with 5 kg water at 20°C. Then final amount of water in the mixture would be; Given specific heat of ice = 0.5cal/g°C, specific heat of water = 1 cal/g°C, Latent heat of fusion of ice = 80 cal/g.

Physics · Thermodynamics

G1 Physics · Accepted Answer

Apply energy conservation. Sensible heat is Q=mcΔT and phase-change heat is Q=mL. Heat lost by hotter parts equals heat gained by colder parts. Evaluating the given data/statements gives 6 kg. Therefore the correct answer is A.