Question

A solid metal weighing 150 g melts at its melting point of 800 °C by providing heat at the rate of 100 W. The time taken for it to completely melt at the same temperature is 4 min. What is the specific latent heat of fusion of the metal?

Answer 1

Given:

m = 150g = 150 × 10^(-3) kg = 0.15 kg

Power (P) = 100W,

Time (t) = 4 min = 4 × 60 sec

The amount of heat supplied in 4 min

Heat energy (Q) = 100 × 4 × 60 = 24000 J

This heat energy is used in melting.

Let L be the latent specific heat.

∴ L = `"Q"/"m"`

∴ L = `24000/0.15`

= 1.6 × 10⁵ J kg^-1