No, light does not become mass. In the theory of special relativity, which is a fundamental theory of physics developed by Albert Einstein, light is described as massless particles called photons. Photons are particles of electromagnetic radiation, and they travel at the speed of light in a vacuum.
According to Einstein's famous equation E=mc², energy (E) and mass (m) are two forms of the same thing, related by the speed of light (c). This equation shows that mass can be converted into energy and vice versa. However, light itself does not possess mass. It consists of photons, which have zero rest mass.
While photons carry energy and momentum, they do not have rest mass. Rest mass refers to the mass of an object when it is at rest, and it is the mass that appears in the equation E=mc². Since photons are always moving at the speed of light, they do not have a rest frame, and their mass is zero.
In summary, light is composed of massless particles called photons, and it does not have mass.