$A$ photon is associated with .........

$A$ photon of frequency $f$ has a momentum associated with it. If $c$ is the velocity of light,the momentum is:

How is the intensity of radiation determined?

The momentum of a photon with energy $20 \, eV$ is

Consider a hypothetical annihilation of a stationary electron with a stationary positron. What is the wavelength of the resulting radiation? ($h =$ Planck's constant,$c =$ speed of light,$m_0 =$ rest mass)

The number of photons emitted by a $10\,W$ bulb in $10\,s,$ if the wavelength of light is $1000\,\mathring{A},$ is: