Describe the electromagnetic spectrum.

When electromagnetic radiation of wavelength $300 \, nm$ falls on the surface of a metal,electrons are emitted with the kinetic energy of $1.68 \times 10^5 \, J \, mol^{-1}$. What is the minimum energy needed to remove an electron from the metal? $(h = 6.626 \times 10^{-34} \, J \, s, c = 3 \times 10^8 \, m \, s^{-1}, N_A = 6.022 \times 10^{23} \, mol^{-1})$

If $p$ is the momentum of the fastest electron ejected from a metal surface after the irradiation of light having wavelength $\lambda$,then for $1.5 \ p$ momentum of the photoelectron,the wavelength of the light should be: (Assume kinetic energy of ejected photoelectron to be very high in comparison to work function)

Electromagnetic radiations of frequency $\nu$ consist of a stream of particles called photons. Which of the following statements is / are true about photons:

What is the photoelectric effect? Explain it.

Explain the reason for the formation of a spectrum.