Question

A molten metal weighing 150 g is kept at its melting point 800 °C, when the metal is allowed to solidify at the same temperature, it releases 75,000 J of heat energy. What is the specific latent heat of the metal?

Answer 1

The metal is solidifying at its melting point, so the temperature remains constant and the heat released is only latent heat.

Heat released, Q = 75,000 J

Mass of metal, m = 150 g = 0.150 kg

Using Q = mL

\[L = \frac{Q}{m}\]

= \[\frac{75000}{0.150}\]

= 5,00,000 J/kg

Therefore, the specific latent heat of fusion of the metal is 5 × 10⁵ J/kg (or 500 J/g).