What is called as the quantum of energy? What is its energy?

$A$ particle which has zero rest mass and non-zero energy and momentum must travel with a speed

Which of the following phenomena cannot be explained by the wave theory of light?

$A$ photon of wavelength $\lambda$ is scattered from an electron,which was at rest. The wavelength shift $\Delta \lambda$ is three times of $\lambda$ and the angle of scattering $\theta$ is $60^o$. The angle at which the electron recoiled is $\phi$. The value of $\tan \phi$ is: (electron speed is much smaller than the speed of light)

Monochromatic light of wavelength $3000 \, \mathring{A}$ is incident on a surface of area $4 \, cm^2$. If the intensity of light is $150 \, mW/m^2$, then the rate at which photons strike the target is:

The curve drawn between the velocity and frequency of a photon in a vacuum will be a