$\begin{aligned}
& \mathrm{E}=\mathrm{hf} \
& \mathrm{ML}^2 \mathrm{T}^{-2}=[\mathrm{h}] \times\left[\mathrm{T}^{-1}\right] \
& {[\mathrm{h}]=\left[\mathrm{ML}^2 \mathrm{T}^{-1}\right]} \
& \mathrm{L}=[\mathrm{MVR}]=\left[\mathrm{ML}^2 \mathrm{~T}^{-1}\right] \
& \mathrm{L}=\frac{\mathrm{nh}}{2 \pi}
\end{aligned}$
L is integral multiple of 2πh