What is a photon?

What is photon?

Whenever a hydrogen atom emits a photon in the Balmer series

The energy of a photon is given as: DeltaE//"atom"=3.03xx10^(-19)J"atom"^(-1) . The wavelength (lamda) of its photon is

Define intensity of radiation on the basis of photon picture of light. Write its S.I. unit.

Monochromatic light of wavelength 632.8 nm is produced by a helium-neon laser. The power emitted is 9.42 mW. (a) Find the energy and momentum of each photon in the light beam, (b) How many photons per second, on the average, arrive at a target irradiated by this beam? (Assume the beam to have uniform cross-section which is less than the target area), and (c) How fast does a hydrogen atom have to travel in order to have the same momentum as that of the photon?

Mention any three properties of a photon.

What is the speed of photon in free space?

What is the mass of a photon of sodium light with a wavelength of 5890 Å? [h = 6.626 xx 10^(-34) Js]