Find the dimensions of Planck's constant $h$ from the equation $E=hv$, where $E$ is energy and $v$ is frequency.

The height $\left(h\right)$ of mercury column in a barometer is found to be $76 \mathrm{cm}$. Calculate the atmospheric pressure in $\mathrm{SI}$ and$\mathrm{CGS} \mathrm{units}$.

Given: Specific gravity of mercury $=13.6$, density of water $=1\mathrm{g}/\mathrm{cc}$ and $\mathrm{g}=9.8 \mathrm{m}/{\mathrm{s}}^2$. Formula for pressure is $p=hpg$.