Are all photons particles of light?

Question

I am reading Richard Feynman's QED and am a bit confused. If light consists of photon particles, then are all photons particles of light? What is the implication of this?

Answer 1

Visible Light is made of photons of a certain frequency and wavelength - the visible light we see forms only a tiny part of the Electromagnetic spectrum between 400 and 700 nanometres.

The full EM spectrum which goes from radio waves (wavelength can be several metres long up to 1000metres) to Gamma Rays (which are tiny around ~10^-12 metres long.)

The smaller the wavelength, the higher the frequency - as all EM waves travel at the speed of light in a vacuum from the relationship(c = f x lambda).

The waves with higher frequencies carry more energy from the other relationship E = h x f (where h is a constant called Plancks constant - and is very tiny @ 6.63 x 10^-34 J s.)

The main result of this, is that higher frequency waves are more harmful to biological things - i.e. When you have an X-Ray, you wear the large lead apron thing to absorb most of the energy from the rays. (X-Rays are really called X-Ray Photons)

All EM waves are photons - radio photons, visible photons etc...
Just think of a photon as a small packet of energy.

The link gives quite a good page for a simple explanation...

http://csep10.phys.utk.edu/astr162/lect/light/spectrum.html

Answer 2

The short answer is yes. I'm not sure if I can be more lucid than Feynman, but I'll try to help you out.

In applying quantum theory to electromagnetism, we treat light as a particle that is governed by a wave function. The wave function is what we calculate, and its square modulus is the probability that we'll find the photon in any given place. This wave function is what causes large amounts of photons to act like an "electromagnetic wave" in classical theory.

The implication of this is that if you are dealing with a large number of photons, averaging over the wave functions allows you to treat the system as a classical electromagnetic wave. If you're dealing with just a few photons, though, then you can't do a good average, and you'll need to treat them as individual particles.

Answer 3

Electrons, protons and neutrons are very very small, an atom is almost completely empty area. yet that is not any longer the reason, photons do paintings mutually with electron shells electromagnetically as photon are electromagnetic power and the electrons have an electromagnetic stress. that is the association of the atoms in the molecule and the arrangements of the molecules that make certain no matter if it is clear, translucent or opaque. Glass is more often than not silicon dioxide and so is sand, were it basically the atoms, both will be clear yet sand for sure isn't. there is easily a advise route through glass in the previous the photon hits some thing and is redirected yet like detours redirect site visitors round an impediment, the gentle is redirected through the glass. that is the geometry of the atoms that provides it refraction and we are in trouble-free terms basically getting to attraction to close that with meta-resources.