What do think is photon a quanta?

[AGBROKO EJOVWOKE]

what do think is photon a quanta?
it is true to me that it is a quanta but i wish to gather solid evidence. i was think to gather evidence from photoelectric effect please see if you can give me additional insight

 

[mathman]

The basic argument (Einstein) was that increasing intensity led only to more electrons if they could be emitted. However if the wavelength was too long to produce photoelectrons, increasing intensity didn't help.