Question

An immersion heater at 500 W is fitted into a large block of ice at 0'C. how long does it take to melt 1.5 kg of ice ?

Answer 1

It would take `10^3` seconds or 16.66 min.

The latent heat of fusion of ice = 333J/g

The mass of ice = 1.5kg = `1.5xx10^3g`

So the amount of heat energy required to melt the ice = `333xx1.5xx10^(3)=500xx10^(3)J`

The power rating of the heater = 500W. This means it is delivering 500 Joules per second.

So it will take `(500xx10^(3))/(500)s` to deliver the required amount of energy = `10^(3)s` or 16.66 min.