If $R$ is the Rydberg constant in ${\mathrm{cm}}^{-1}$, then hydrogen atom does not emit any radiation of wavelength in the range of

To which of the following the angular velocity of the electron in the $n^{\mathrm{th}}$ Bohr orbit is proportional?

How the linear velocity$v$ of an electron in the Bohr orbit is related to its quantum number $n ?$