What is scattering? Which property of electromagnetic radiation can explain it? Explain.

The energy of one mole of photons of radiation of frequency $2 \times 10^{12} \ Hz$ in $J \ mol^{-1}$ is $.....$ (Nearest integer) (Given: $h = 6.626 \times 10^{-34} \ Js$,$N_A = 6.022 \times 10^{23} \ mol^{-1}$)

Calculate the energy of one mole of photons of radiation whose frequency is $5 \times 10^{14} \ Hz$.

What is the ratio of the energy of photons having wavelengths $2000 \ \mathring{A}$ and $4000 \ \mathring{A}$?

What is the charge on $\gamma$-rays?

$A$ metal surface is exposed to solar radiation.