What we say we know is determined by experimental evidence and the success of various theories we construct to predict these results. All measurements known support the notion that the photon is massless. One cannot really say more.fxdung said:Why we know that average speed of a single photon(in point particle view) equal the speed of EM wave?If average speed of a single photon smaller than c then there exist massive photons?
There is no such thing; there is no valid "point particle view" of a photon.fxdung said:average speed of a single photon(in point particle view)
The average speed of a single photon is equal to the speed of an electromagnetic (EM) wave, which is approximately 299,792,458 meters per second in a vacuum.
This has been confirmed through numerous experiments and observations, including the famous Michelson-Morley experiment and the more recent experiments involving quantum entanglement. Additionally, the speed of light is a fundamental constant in physics and is a key component of the theory of relativity.
Knowing the average speed of a single photon is crucial in understanding the behavior of light and how it interacts with matter. It also has practical applications in fields such as telecommunications, where the speed of light is used to transmit information.
Yes, the average speed of a single photon is always equal to the speed of an EM wave in a vacuum. However, in certain mediums such as water or glass, the speed of light may be slower due to interactions with the particles in the medium.
No, according to the theory of relativity, the speed of light is the maximum speed at which any object or information can travel. This applies to single photons as well, so the average speed of a single photon cannot be faster than the speed of light.