When a beam of light passes from a material of higher optical density to a material of lower optical density, the angle of incidence is greater than the angle of refraction. This is due to Snell's Law, which states:

n₁sinθ₁ = n₂sinθ₂

where:

* n₁ is the refractive index of the first medium (higher optical density)

* θ₁ is the angle of incidence

* n₂ is the refractive index of the second medium (lower optical density)

* θ₂ is the angle of refraction

Since n₁ > n₂, for the equation to hold true, θ₁ must be greater than θ₂. This means the light bends away from the normal as it enters the less dense medium.

In simpler terms:

* Higher optical density: Light travels slower and bends towards the normal.

* Lower optical density: Light travels faster and bends away from the normal.