The Speed of Light: Comparing Photon and EM Wave Velocities

[fxdung]

Velocity of photon allways is c(photon is massless particle).While velocity of EM wave in medium < c.So does velocity of photon need not allways equal velocity of EM wave?

 

[DaveE]

A photon is an EM wave. Two names for the same thing, just different languages (classical vs. quantum).

 

[fxdung]

So velocity of photon is difference with classical EM wave(superposition of many photons)'s velocity?

 

[DaveE]

So velocity of photon is difference with classical EM wave(superposition of many photons)'s velocity?

No. Photons and EM waves move at the same speed. They are the same thing.

 

[fxdung]

But in medium speed of photon is c but speed of light is v<c?

 

[DaveE]

But in medium speed of photon is c but speed of light is v<c?

No. THEY ARE THE SAME. It's just two different ways of modeling reality. The quantum approach (photons) is more accurate, but the classical approach (waves) is amazingly good (for something that's wrong) at solving large scale scale EM problems with easier math.

Check out this video. They'll explain it better than I can.

 

[PeterDonis]

Velocity of photon allways is c(photon is massless particle).While velocity of EM wave in medium < c.So does velocity of photon need not allways equal velocity of EM wave?

You are trying to mix together a classical model of light and a quantum model of light. That doesn't work.

Furthermore, you already have an open thread where this same confusion has been addressed:

https://www.physicsforums.com/threa...t-wavetrain-corresponding-with-photon.999282/

So there's no point in having this separate thread open to rehash the same confusion.

Thread closed.