Question

Assertion: The temperature starts changing as soon as a solid starts melting. Reason: The amount of heat required to change one kg of solid into liquid at atmospheric pressure at its melting point is called latent heat of fusion.​

Answer 1

Assertion: The temperature starts changing as soon as a solid starts melting.

Reason: The amount of heat required to change one kg of solid into liquid at atmospheric pressure at its melting point is called latent heat of fusion.

ASSERTION IS FALSE, BUT REASON IS TRUE.

• Whenever any substance undergoes change in state of matter, the temperature remains same (i.e. doesn't change during the process).

• For example : When water boils (i.e. changes from liquid to vapour state), the temperature remains at 100°C and doesn't change.

• Similarly, when ice melts into water, the temperature remains at 0°C and doesn't change. This is because the heat supplied is getting used up to change the state of matter instead of the temperature (that's why called LATENT HEAT OF FUSION).

• "Latent" means hidden , hence this heat cannot be perceived since temperature change doesn't occur.

$\star$ Hope It Helps.