If a ray of light enters from a rarer medium to a denser medium at zero angle of incidence, it would

When a light ray enters into glass medium from water at an angle of incidence 0°, what would be the angle of refraction?

A ray of light travelling from a rarer medium to a denser medium

When a ray of light travels from a denser medium to a rarer medium then

Refraction of light, as it enters from one transparent medium to another, is due to

When a light ray passes through from air to water with a non-zero angle the ray will be