Light travels from water (n = 1.33) into air (n = 1.00). If the angle of incidence in water is 30°, what is the angle of refraction in air? (Use Snell's law: n1 sin θ1 = n2 sin θ2, and take sin 30° = 0.5)
Show the answer and explanation
Correct answer
C. 42°
Principle or equation
Snell's law: n1 sin θ1 = n2 sin θ2.
Why this answer is correct
1.33 * sin 30° = 1.00 * sin θ2 => 1.33 * 0.5 = sin θ2 => sin θ2 = 0.665. θ2 ≈ 41.7°, which rounds to 42°.
Example
If n1 = 1.5 and θ1 = 30°, then sin θ2 = 0.75, θ2 ≈ 49°.
This published item includes a stored explanation and passed the platform’s publication workflow. It is independent preparation material, not a claim of an official or recalled examination question.