The ground state energy of a $H$ atom is given as $-13.6 \, eV$. The energy of the second excited state will be .......... $eV$.

The energy required (in $eV$) to excite an electron of $H$-atom from the ground state to the third excited state is

Supposing the energy (in arbitrary units) of the energy levels in the hydrogen atom is given as under:

Energy level	$K$ $(n=1)$	$L$ $(n=2)$	$M$ $(n=3)$	$N$ $(n=4...n=\infty)$
Energy	$-864 \ a.u.$	$-216 \ a.u.$	$-96 \ a.u.$	$0 \ a.u.$

The excitation energy needed to raise the electron from $M$ level to $n = \infty$ would be:

Light of frequency $1.6 \times 10^{16} \ Hz$ falling on a metal plate emits electrons that have double the kinetic energy compared to the kinetic energy of electrons emitted when light of frequency $1.0 \times 10^{16} \ Hz$ falls on the same plate. The threshold frequency $(v_0)$ of the metal in $Hz$ is:

In a hydrogen atom,electrons are excited to the $5^{th}$ quantum level. How many different spectral lines may appear in the emission spectrum?

As we move away from the nucleus,the energy of the electron