A ray of light which strikes a glass slab from air at normal incidence passes through the slab?

A. undeviated and undisplaced at a lower speed
B. deviated and undisplaced at a lower speed
C. deviated and displaced at a lower speed
D. undeviated and displaced at a faster speed

Correct Answer:

Option A – undeviated and undisplaced at a lower speed

Explanation

The angle of refraction will be zero as the angle of incidence is zero in this case. This is a rule, that whenever a ray strikes perpendicularly or normally to a surface, no refraction will take place and hence the ray will pass through without deviating from its path.