The spectrum of helium is similar to which of the following?

Which statement relating to the spectrum of $H$ atom is false:

The ratio of the radii of the $3^{rd}$ and $5^{th}$ orbits of $He^+$ is ..... . (Atomic number of $He = 2$,$r = 0.529 \times \frac{n^2}{Z} \ \mathring{A}$)

Values of work function $(W_0)$ for a few metals are given below:

Metal	$Li$	$Na$	$K$	$Mg$	$Cu$	$Ag$
$W_0 / eV$	$2.42$	$2.3$	$2.25$	$3.7$	$4.8$	$4.3$

The number of metals which will show photoelectric effect when light of wavelength $400 \ nm$ falls on it is $........$.
Given: $h = 6.6 \times 10^{-34} \ J \ s$,$c = 3 \times 10^8 \ m \ s^{-1}$,$e = 1.6 \times 10^{-19} \ C$

Calculate the longest wavelength in the hydrogen emission spectrum of the Lyman series $\left(R_H = 109677 \ cm^{-1}\right)$.

As we move away from the nucleus,the energy of the electron