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An icebox made of 1.5 cm thick styrofoam has dimensions 60 cm x 60 cm x 30 cm and contains ice at 0 deg C in a room at 40 deg C. Using latent heat of fusion of ice = 3.36 x 10⁵ J/kg and thermal conductivity of styrofoam = 0.04 W/m/deg C, find the rate at which ice melts.

1. 0.23 g/s
2. 0.46 g/s
3. 0.69 g/s
4. 0.92 g/s

Correct answer: 0.46 g/s

Solution

Total area is 1.44 m², giving Q = 153.6 W and a melting rate of about 0.46 g/s.

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