The antiparticle of an electron is:

The Compton effect supports the fact that

The velocity of photons is proportional to (where $\nu=$ frequency)

In pair annihilation,an electron and a positron destroy each other to produce gamma radiation. How is the momentum conserved?

$A$ $2\,mW$ laser operates at a wavelength of $500\,nm.$ The number of photons that will be emitted per second is [Given Planck's constant $h = 6.6 \times 10^{-34}\,Js,$ speed of light $c = 3.0 \times 10^8\,m/s$]

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