Electromagnetic radiation with maximum wavelength is

Choose the correct statements in reference to the photoelectric effect. $(i)$ There is no time lag between the striking of light and ejection of electrons from the metal surface. $(ii)$ The number of electrons ejected is independent of the intensity of light. $(iii)$ The elements $K$, $Rb$ and $Cs$ can show photoelectric effect when exposed to the beam of light.

Identify the region of the electromagnetic spectrum for the spectral lines when electron transition takes place from higher energy levels to $n=3, 4, 5$ in the atomic spectrum of hydrogen.

The work functions $(W_0)$ of $K, Na, Li, Mg$ and $Cu$ are $2.25, 2.30, 2.42, 3.70$ and $4.80 \ eV$ respectively. How many of these metals do not undergo photoelectric effect when a radiation of wavelength $450 \ nm$ is allowed to fall on them? $(1 \ eV = 1.602 \times 10^{-19} \ J)$

Which of the following is not a property of photons?

$a$,$b$,$c$,$d$ are electromagnetic radiations. Frequencies of $a$,$b$ are $3 \times 10^{15} \ Hz$,$2 \times 10^{14} \ Hz$,respectively,whereas wavelengths of $c$,$d$ are $400 \ nm$,$750 \ nm$,respectively. The increasing order of their energies is