If L and R denote inductance and resistance respectively, then the dimensional formula of L/R is:

time constant DURING the growth of  LR CIRCUIT IS  τ=LRIn M(meter)-K(kilogram)-S(second)-Q(charge) system, SO   LR   will have the dimensions of time. Energy stored in inductor is U=12Li2Heat developed in resistor is, H=i2Rt; Equating both L=Rt or L/R= t. (or)Dimension of L=M1L2T0Q-2Dimension of R=M1L2T-1Q-2Dimension of L/R =M1L2T0Q-2M1L2T-1Q-2=M0L0TQ0