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

A. The energy of a photon is E = hv

B. The velocity of a photon is c.

C. The momentum of a photon, p = hv/c

D. In a photon-electron collision, both total energy and total momentum are conserved.

E. Photon possesses positive charge.

Choose the correct answer from the options given below :

We examine each statement about a photon and decide whether it is true or false.

Statement A: “The energy of a photon is E = hv”.

The fundamental relation between the energy E of a photon and its frequency v (or ν) is given by Planck’s equation

$E\; =\; h·v$

where h = 6.626 × 10⁻³⁴ J·s is Planck’s constant. This relation follows directly from quantum theory and is experimentally verified (photoelectric effect, spectral lines, etc.). Hence statement A is correct.

Statement B: “The velocity of a photon is c”.

In vacuum, light propagates at the universal constant c ≈ 3.00 × 10⁸ m/s. Photons are the quanta of electromagnetic radiation, and each photon travels at the same speed c when no medium is present. Therefore statement B is correct.

Statement C: “The momentum of a photon, p = hv/c”.

Photon momentum can be expressed using the energy–momentum relation for a mass‑less particle:

$p\; =\; \backslash frac\{E\}\{c\}$

Substituting the energy from statement A (E = hv) gives

$p\; =\; \backslash frac\{hv\}\{c\}$

This is the standard expression for photon momentum, confirming that statement C is correct.

Statement D: “In a photon‑electron collision, both total energy and total momentum are conserved.”

All closed physical systems obey the conservation laws of energy and momentum, regardless of the particles involved. In a photon‑electron interaction (e.g., Compton scattering), the combined system of photon + electron conserves total energy (including the photon’s energy hv and the electron’s kinetic energy) and total momentum (vector sum of photon momentum hv/c and electron momentum). Hence statement D is correct.

Statement E: “Photon possesses positive charge.”

Photons are electrically neutral; they carry zero electric charge. This is essential for the long‑range nature of the electromagnetic force and is confirmed experimentally (no deflection of light by electric or magnetic fields). Therefore statement E is false.

Collecting the true statements gives us the option that includes A, B, C and D but excludes E.

The correct answer is A, B, C and D only.