If the shortest wavelength of $H$ atom in Lyman series is $x$,then the longest wavelength in Balmer series of $He^{+}$ is

For $Li^{2+}$,the ratio of radii $r_2 : r_5$ is:

The energy levels for a hydrogen-like species with atomic number $Z$ can be given by:

When an electron drops from a higher energy level to a lower energy level,then

The frequency of one of the lines in the Paschen series of a hydrogen atom is $2.340 \times 10^{11} \ Hz$. The quantum number $n_2$ which produces this transition is

State whether the following statements are true or false:
$(i)$ When an electron in a hydrogen atom returns from the third excited state to the ground state,it emits frequencies corresponding to lines in the Lyman,Balmer,and Paschen series.
$(ii)$ When an electron in a hydrogen atom returns from the third excited state to the ground state,it emits radiation with wavelengths corresponding to the Pfund series,which has very high frequencies.