What is the maximum number of emission lines when the excited electron of an $H$ atom in $n=6$ drops to the ground state?

Match the principles given in List-$I$ with their discoverers given in List-$II$.

List-$I$	List-$II$
$(1)$ Exclusion Principle	$(A)$ Hund
$(2)$ Multiplicity Rule	$(B)$ Heisenberg
$(3)$ Uncertainty Principle	$(C)$ Einstein
$(4)$ Quantum Theory	$(D)$ Planck
	$(E)$ Pauli

With increasing principal quantum number,the energy difference between adjacent energy levels in $H$ atom

If $n=2$ for $He^{+}$ ion,then what is the wavelength in $\mathring{A}$?

The longest wavelength line in the Lyman series of the $H$ atom spectrum is $:-$

Which of the following statements are correct,if the threshold frequency of caesium is $5.16 \times 10^{14} \ Hz$?
$A.$ When $Cs$ is placed inside a vacuum chamber with an ammeter connected to it and yellow light is focused on $Cs$,the ammeter shows the presence of current.
$B.$ When the brightness of the yellow light is dimmed,the value of the current in the ammeter is reduced.
$C.$ When a red light is used instead of the yellow light,the current produced is higher with respect to the yellow light.
$D.$ When a blue light is used,the ammeter shows the formation of current.
$E.$ When a white light is used,the ammeter shows the formation of current.
Choose the correct answer from the options given below: