Art Unwin wrote:
The books state that a photon is a particle without mass.

Photons have no *rest* mass but since they must necessarily
move at the speed of light in a medium, they indeed do have
mass because of their momentum. The mass of a photon is
equal to Planck's constant divided by (the product of the
speed of light times the wavelength), i.e. m=h/(c*lamda).

The photon as a particle cannot be a wave since its extremities cannot
be determines as with a particle.

On the contrary, double slit experiments prove that a single
photon can go through both slits and interfere with itself on
the other side. If you design a test to prove a photon is a
wave, it will respond like a wave (even if it is a single photon).
If you design a test to prove a photon is a particle, it will
respond like a particle. The duality is related to the
uncertainty principle.

The main point is that the physical manifestation of RF
electromagnetic fields are clouds of photons. The fields and
the photons are the same thing. Those EM fields have been proven
to be quantized. Photons are the particles that quantize the EM
field.
--
73, Cecil http://www.w5dxp.com