The rest mass of the photon is
0
∞
Between 0 and ∞
Equal to that of an electron
[MP PET 1994; CPMT 1996; RPMT 1999; JIPMER 2002]
How to justify that the rest mass of a photon is zero?
If the momentum of a photon is p, then its frequency is Where m is the rest mass of the photon