The ratio between kinetic energy and the total energy of the electrons of a hydrogen atom according to Bohr's model is

The energy required for the ionisation of a hydrogen atom is $13.6 \ eV$. What is the energy required for the ionisation of $He^+$ ion (in $eV$)?

If the potential energy of an electron in the second orbit of $He^+$ is $-27.2 \, eV$,then calculate the double value of the energy of the first excited state of a hydrogen atom in $eV$.

Which of the following represents the wavelength of a spectral line of the Balmer series of the $He^{+}$ ion? ($R=$ Rydberg constant,$n > 2$)

The energy of an electron in a hydrogen atom when present in $n=1$, $n=2$, and $n=3$ will be in the ratio of:

If an electron moves from an excited state to the ground state in multiple steps in the hydrogen spectrum,and the number of lines in the visible region is $4$,then the number of lines in the infrared region is: