An expression of energy density is given by u=αβsin(αxkt). Where α,β are constants, x is displacement, k is Boltzmann constant and t is the absolute temperature. The dimensions of β will be:
(4)
sin(αxkt)=Dimensionless
∴ α[L][ML2T-2]=[M0L0T0]⇒α=[MLT-2]
αβ=EnergyVolume=[ML2T-2][L3]
⇒β=[MLT-2][L3][ML2T-2]
=[M0L2T0]