Which of the following definitions of latent heat of fusion is correct?
1
The amount of heat energy that is required to change 1 kg of a solid into liquid at atmospheric pressure at its melting point is known as the latent heat of fusion.
2
The amount of heat energy that is required to change 10 kg of a solid into liquid at atmospheric pressure at its melting point is known as the latent heat of fusion
3
The amount of heat energy that is required to change 1 g of a gas into liquid at atmospheric pressure at its melting point is known as the latent heat of fusion.
4
The amount of heat energy that is required to change any amount of a solid into liquid at atmospheric pressure at its melting point is known as the latent heat of fusion.