Respuesta :
The correct answer for the question that is being presented above is this one: "It does not change." The angle of the wave if it hits the Perspex which is at 90 degrees will stay the same and will not change.
The relation between the angle of incidence and the angle of refraction is known as Snell's Law. Since the light travels with different speed in different media, the direction of the ray of light will change when it crosses the boundary between the two media.
