What is the angular momentum of an electron in the fourth orbit of a hydrogen atom?

When a photon of energy $12.75 \, eV$ is completely absorbed by a hydrogen atom in its ground state,the principal quantum number of the excited state will be:

If the shortest wavelength of the hydrogen atom in the Lyman series is $x$,then the longest wavelength in the Balmer series of $He^+$ is:

What will be the energy of an electron emitted from the ground state to the $n^{th}$ orbit?

The ratio of minimum wavelengths of Lyman and Balmer series will be $:-$

Which one of the following corresponds to the wavelength of a line in the Balmer series of the $H$ atom spectrum? $(R =$ Rydberg constant$)$