What is a photon? o a vibrating electron. o a particle or packet of light. o a protostar. oa kind of spectrum.

A particle or packet of light.

Explanation:

A photon essentially doesn't have a charge and thus can't be called an electron. So, option 1 is incorrect.

Photons are in fact packets of electromagnetic energy that light is made up of. So, option 2 is correct.

A photon is not a gaseous mass that indicates the preliminary stage in a star's growth and thus can't be a protostar. So, option 3 is incorrect.

Photons having different energies are constituents of the electromagnetic spectrum and thus a single photon can't be a spectrum. So, option 4 is incorrect.