Question

When a ray of light travels perpendicular to the surface of separation of two mediums, it

• A. Bends towards the normal
• B. Bends away from the normal
• C. Goes without any deviation
• D. None of these

Answer 1

Answer: (C)

Refraction happens when light enters a medium where its speed is different or when it passes from a fast medium to a slow medium. If a ray of light is incident normally to the surfaces, then deviating from the normal will always increase the time of travel according to the Snell’s law.

According to which,

Sine (angle of incidence)*index of refraction of the incident medium=sine (angle of refraction)* index of refraction of the refractive medium
Since angle of incidence is 0 degrees, sine (0)=0.

So, the light ray will pass without any deviation.