Calculate the velocity of an electron placed in $III$ orbit of H atom.Also calculate the no of revolution /sec round the nucleus.

Question

$\begin{array}{1 1}(a)\;7.29\times 10^7cmsec^{-1}&(b)\;7.30\times 10^2cmsec^{-1}\\(c)\;8.39\times 10^7cmsec^{-1}&(d)\;7.29\times 10^3cmsec^{-1}\end{array}$