A parallel beam of light of wavelength $900\,nm$ and intensity $100\,Wm ^{-2}$ is incident on a surface perpendicular to the beam. Tire number of photons crossing $1\,cm ^{2}$ area perpendicular to the beam in one second is :

If the total energy transferred to a surface in time $t$ is $6.48 \times 10^5 \mathrm{~J}$, then the magnitude of the total momentum delivered to this surface for complete absorption will be :

A photon of $1.7 \times {10^{ – 13}}$ Joules is absorbed by a material under special circumstances. The correct statement is

An electron and a photon each have a wavelength of $1.00\; nm$. Find

$(a)$ their momenta,

$(b)$ the energy of the photon, and

$(c)$ the kinetic energy of electron.

Frequency of photon having energy $66 eV$ is