How to Use Snell's Law of Refraction?

To use Snell's Law, follow these steps:

1. Identify the two media and find their refractive indices (n₁ and n₂)
2. Measure or identify the angle of incidence (θ₁) from the normal
3. Apply the formula: n₁ sin θ₁ = n₂ sin θ₂
4. Solve for the unknown angle: θ₂ = sin⁻¹[(n₁ sin θ₁) / n₂]

Remember, angles are always measured from the normal (perpendicular line) to the surface, not from the surface itself.