When light is incident along the normal and passes from air to water, then the direction of light will _____________.

Correct option is A

The correct answer is (A)  ​not be changed

• When light is incident along the normal (perpendicular) to the surface and passes from air to water, the direction of light will remain unchanged.

Information booster:

• This happens because refraction, or bending of light, occurs only when light strikes the surface at an angle other than 90° (not along the normal).
• When the light is incident perpendicular to the surface, there is no bending as the light enters the new medium; it simply slows down or speeds up depending on the refractive indices of the media.
• The light slows down because water has a higher refractive index than air.
• However, the light continues to move in the same straight direction.