What is the energy associated with the first orbit of $Li^{2+}$ $(R_{H} = 2.18 \times 10^{-18} \ J)$?

The four lowest energy levels of the $H$ atom are shown in the figure. The number of emission lines will be ...... .

In $He^{+}$ ion,the energy of $2^{nd}$ orbit is $-13.6 \ eV/atom$. The kinetic energy of the same orbit for $He^{+}$ ion will be:

If the work function of a metal is $6.63 \times 10^{-19} \ J$,the maximum wavelength of the photon required to remove a photoelectron from the metal is $.... \ nm$. (Nearest integer)
[Given : $h = 6.63 \times 10^{-34} \ J \ s$,and $c = 3 \times 10^{8} \ m \ s^{-1}$ ]

For a hydrogen-like species,the ratio of velocities of electrons in the $I, II,$ and $III$ orbits,i.e.,$V_1 : V_2 : V_3$,will be:

The quantity $h \nu / K_{B}$ corresponds to