Snell's Law describes the relationship between the angles of incidence and refraction when a light ray passes through the boundary between two different isotropic media, like air and glass. It also states that the incident ray, the refracted ray, and the normal to the surface at the point of incidence all lie in the same plane.
Here's a breakdown:
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The fundamental relationship: Snell's Law is mathematically expressed as:
n₁ sin θ₁ = n₂ sin θ₂
Where:
- n₁ is the refractive index of the first medium.
- θ₁ is the angle of incidence (angle between the incident ray and the normal).
- n₂ is the refractive index of the second medium.
- θ₂ is the angle of refraction (angle between the refracted ray and the normal).
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Planarity: The incident ray, the refracted ray, and the normal to the surface all lie in the same plane. This is crucial for understanding the geometry of refraction.
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Constant Ratio: For a specific pair of media and a specific wavelength of light, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. This constant is equal to the ratio of the refractive indices of the two media (n₂/n₁).
In summary, Snell's Law governs how light bends when it moves from one medium to another, defining the relationship between incident and refracted angles based on the refractive indices of the materials involved, and confirming that all relevant rays lie in the same plane.
