As an electron moves away from the nucleus,its potential energy

The maximum energy is possessed by an electron when it is present:

If the wavelength of the limiting line of the Lyman series of the hydrogen atom is $16$ times the wavelength of the limiting line of the same series for an ion $X$,then what is $X$?

The energy level for $A^{(+z-1)}$ is given by which of the following expressions?

The radius of the $2^{nd}$ orbit of $Li^{2+}$ is $x$. The expected radius of the $3^{rd}$ orbit of $Be^{3+}$ is:

Which transition in the hydrogen spectrum would have the same wavelength as the Balmer type transition from $n = 4$ to $n = 2$ of $He^+$ spectrum?