Q.

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:

1 [ML2T-2θ-1]  
2 [M0L2T-2]  
3 [M0L0T0]  
4 [M0L2T0]  

Ans.

(4)

sin(αxkt)=Dimensionless

∴ α[L][ML2T-2]=[M0L0T0]⇒α=[MLT-2]

αβ=EnergyVolume=[ML2T-2][L3]

⇒β=[MLT-2][L3][ML2T-2]

=[M0L2T0]