What is the shortest wavelength in the $Pfund$ series of $He^{+}$ ion?

The ratio of the velocity of an electron in the second orbit of $He^{+}$ to the third orbit of $B^{4+}$ is:

When an electron jumps from $n = 5$ to $n = 2$ with all possible transitions,which of the following statements is correct?

If the ionization energy of a hydrogen atom is $E$,then the ionization energy of $Li^{2+}$ will be ............ $E$.

In the hydrogen spectrum,a line corresponds to a transition from the $3^{rd}$ to the $5^{th}$ orbit. Identify the series to which this transition belongs.

Match the following for hydrogen atom $(Z=1)$ :-

$(P). \lambda_{\max }$ in Lyman series	$(i). \infty \rightarrow 1$
$(Q). v_{\min }$ in Balmer series	$(ii). 2 \rightarrow 1$
$(R). \lambda_{\min }$ in Lyman series	$(iii). 3 \rightarrow 2$
$(S). v_{\max }$ in Balmer series	$(iv). \infty \rightarrow 2$