What is the energy and momentum of a photon having frequency $v$?

An $AIR$ station is broadcasting waves of wavelength $300 \ m$. If the radiating power of the transmitter is $10 \ kW$,then the number of photons radiated per second is:

What is the charge on a photon?

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)

According to the corpuscular theory of light,the different colours of light are due to

$A$ situation of population inversion is related to