Refraction from water (n = 1.333) into air at 40°

Answer: angle of refraction θ₂ = 58.963° (critical angle 48.607°).

What we know

Refractive index n₁ (incident): 1.333
Angle of incidence θ₁: 40°
Refractive index n₂ (refracting): 1

Step by step

Given: Refractive index n₁ (incident) = 1.333, Angle of incidence θ₁ = 40°, Refractive index n₂ (refracting) = 1
Formula: n₁ · sin(θ₁) = n₂ · sin(θ₂)
Result: Angle of refraction θ₂ = 58.963°

All results

Angle of refraction θ₂	58.963°
Critical angle	48.607°

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The physics

Snell's law describes how light bends when it crosses from one transparent material into another: the product of refractive index and the sine of the angle stays the same on both sides. Light entering a denser medium (higher index) bends toward the normal; entering a lighter one, it bends away.