The velocity of light in a vacuum, which includes photons, is a fundamental constant denoted by the symbol 'c' and has a value of approximately 299,792,458 meters per second. According to the theory of special relativity proposed by Albert Einstein, the speed of light is constant and independent of the wavelength or frequency of the light.
This constancy of the speed of light is one of the fundamental principles of modern physics and has been extensively tested and confirmed by numerous experiments. The speed of light is considered an upper limit for the velocity of any particle with mass. No particle with mass can attain or exceed the speed of light.
The reason for the independence of the velocity of light from its wavelength or frequency lies in the nature of electromagnetic waves and the properties of space and time described by the theory of special relativity.
In special relativity, space and time are intertwined in a four-dimensional framework known as spacetime. The theory introduces the concept of "invariant speed," which is the speed of light in a vacuum. According to this theory, the laws of physics must be the same for all observers moving at constant velocities relative to each other.
When light propagates through space, it does so in the form of electromagnetic waves, which consist of oscillating electric and magnetic fields. The speed at which these fields propagate is determined by the properties of spacetime itself, and it is this invariant speed that remains constant regardless of the wavelength or frequency of the light.
As a consequence, when a photon is emitted, regardless of its wavelength or frequency, it will always travel at the speed of light 'c' in a vacuum. While the energy and momentum of a photon are related to its frequency and wavelength, its velocity remains constant due to the principles of special relativity.