Latent Heat is defined as the heat absorbed or released per unit mass of the substance when the substance changes its phase at the constant temperature.
Latent heat of fusion is defined as the quantity of heat in calories required to transform 1 gm of solid substance at its melting point into liquid of the same temperature.
Dimensional formula of Heat(Q) = M1L2T-2
Dimensional formula of mass = M1L0T0
Putting these values in above equation we get,
Dimensional Formula of Latent Heat = M0L2T-2
SI unit of Latent Heat is Joule kg-1
Note:- Dimensional formula of latent heat of fusion is same as Latent heat. Similarly SI unit of Latent heat of fusion is same as Latent Heat.