Question

Can light is accerated

Answer 1

yes, light is not a accelerated

Answer 2

Acceleration is by definition the change of velocity, which is a vector quantity composed of a magnitude and direction. If either the magnitude or direction changes, we can say that an object is accelerating.

In the case of light, its speed (magnitude) will always be a constant c=3∗108c=3∗108 m/s in a vacuum. If a person were to shoot a laser through different mediums (going from a vacuum to water, from water to air, from air to a vacuum, etc.), these changes would result in light slowing down and speeding up as it passes through each medium, which would be an effective change in the magnitude of velocity.

v=cnv=cn , where n is the index of refraction of the medium.

There are also situations where light encounters a massive object that bends its trajectory (ie. a blackhole). This changes the direction of its velocity vector and would also be considered acceleration