For reflected and refracted rays to be perpendicular, if i is the angle of incidence and r is the angle of refraction, then i+r=90°, giving r=90°−i.
Applying Snell's law: n1sini=n2sinr
2sini=23sin(90°−i)
2sini=23cosi
tani=3
i=60°
An unpolarised light is incident at an interface of two dielectric media having refractive indices of 2 (incident medium) and 23 (medium) respectively. To satisfy the condition that reflected and refracted rays are perpendicular to each other, the angle of incidence is ____.
Held on 24 Jan 2026 · Verified 6 Jul 2026.
45∘
60∘
10∘
30∘
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