n₁ sin θ₁ = n₂ sin θ₂

where:

* n₁ is the refractive index of the first medium (the medium the light is coming from)

* θ₁ is the angle of incidence (the angle between the incoming light ray and the normal to the surface)

* n₂ is the refractive index of the second medium (the medium the light is entering)

* θ₂ is the angle of refraction (the angle between the refracted light ray and the normal to the surface)

To solve for θ₂ (the angle of refraction):

1. Rearrange the formula:

sin θ₂ = (n₁/n₂) sin θ₁

2. Take the arcsine (sin⁻¹) of both sides:

θ₂ = sin⁻¹ [(n₁/n₂) sin θ₁]

Example:

Let's say a light ray is traveling from air (n₁ = 1.00) to water (n₂ = 1.33) at an angle of incidence of 30 degrees. To find the angle of refraction:

1. Plug the values into the formula:

sin θ₂ = (1.00/1.33) sin 30°

2. Calculate:

sin θ₂ ≈ 0.3759

3. Take the arcsine:

θ₂ ≈ sin⁻¹(0.3759) ≈ 22.1°

Therefore, the angle of refraction in this case is approximately 22.1 degrees.