When light travels from air to glass it is called refraction. As it travels, the light ray slows down and bends towards the normal.
The normal is a line drawn at right angles to the boundary of the medium.
Light speed slows down in the glass.
light is refracted when it travels through air and then through glass
prism
The answer depends on the medium which it then travels through.
it travels faster through air.
. . . decreases.
The ratio between the speed of light in vacuum, c, and the speed at which light travels in a material, v, is called the refractive index of the material.The refractive index of air for visible light is 1.000293, so the speed of light in air is c / 1.000293 ≈ 299,705,000 m/s. The refractive index of glass, depending on the type of glass, for visible light is around 1.5, so the light in glass travels at c / 1.5 ≈ 200,000,000 m/s.
Light speed slows down in the glass.
direction
It decreases.
light is refracted when it travels through air and then through glass
Correct.
prism
The answer depends on the medium which it then travels through.
The speed of light is minimum in Glass. It is because light travels at minimum speed in solids.
light in a vacuum
it travels faster through air.