Question

If c is the velocity of light in free space, the correct statements about photon among the following are:

1. The energy of a photon is E = hv.
2. The velocity of a photon is c.
3. The momentum of a photon, ρ = `(h v)/c`.
4. In a photon-electron collision, both total energy and total momentum are conserved.
5. Photon possesses positive charge.

Choose the correct answer from the options given below:

Options

• A, C and D only

• A, B, D and E only

• A and B only

• A, B, C and D only

Answer 1

A, B, C and D only

Explanation:

If c is the velocity of light, E = hv

Hence, the statement (A) is correct.

The velocity of a photon is equal to the velocity of light, i.e. c = h.

Hence, the statement (B) is correct.

Momentum of a photon (ρ) = `h/p`

= `h/eta`

= `(hv)/c`

So the statement (C) is correct.

In a photo-electron collision, total energy and momentum are conserved. Statement (D) is correct as well.

Photons are electrically neutral and are massless. Hence, statement E is incorrect.