Correct Answer - Option 3 : hv/c

__CONCEPT:__

Photon:

- According to Einstein's quantum theory light propagates in the bundles (packets or quanta) of energy, each bundle is called a photon and possessing energy.

The energy of photon:

- The energy of each photon is given by

\(⇒ E = h\nu = \frac{{hc}}{\lambda }\)

Where c = Speed of light, h = Plank's constant = 6.6 × 10–34 J-sec, ν = Frequency in Hz, λ = Wavelength of light

The momentum of the photon:

\(⇒ p = m \times c = \frac{E}{c} = \frac{{h\nu }}{c} = \frac{h}{\lambda }\)

- The relation between the energy and momentum of the photon is given by

\(⇒ p=\frac{E}{c}\)

__EXPLANATION__:

- From the above, it is clear that the
**momentum of a photon of frequency v** is:

⇒ p = hv/c