The ratio of the lowest energy in terms of wave numbers of the Balmer and Lyman series of lines of the atomic spectrum of hydrogen is

Number of waves made by Bohr's electron in one complete revolution in the $3^{rd}$ orbit.

The wavelength of a particular electron transition for $He^{+}$ is $100 \ nm$. The wavelength (in $\mathring{A}$) of $H$ atom for the same transition is

The angular momentum of an electron in a given orbit is $J$. Its kinetic energy will be:

In a hydrogen atom, the minimum energy required to excite an electron from the $2^{nd}$ orbit to the $3^{rd}$ orbit is: (in $eV$)

The wavelength corresponding to an electronic transition between two orbits of a hydrogen atom is $912 \mathring{A}$. The wavelength (in $\mathring{A}$) for the same electronic transition in $Li^{2+}$ is