An equilateral prism deviates a ray through 45° for the two angles of incidence differing by 20°. One of the angle of incidence is (a) 62.5° (b) 32.5° (c) 52.5° (d) 22.5°

Answer: (a). δ = i + e - A ⇒ i + e = 45° + 60° = 105°. By reversibility, the two angles of incidence giving the same δ are i and e: i₁ + i₂ = 105°. i₁ - i₂ = 20° ⇒ i₁ = 62.5°, i₂ = 42.5° So the answer is (a) 62.5°.

An equilateral prism deviates a ray through 45° for the two angles of… | MHT CET 2026 (14 May, Shift 2)

Q6MHT CET 2026 · 14 MAY · SHIFT 2Medium

Prism, Dispersion & Scattering

An equilateral prism deviates a ray through $45^\circ$ for the two angles of incidence differing by $20^\circ$ . One of the angle of incidence is

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Answer: (a)

$\delta = i + e - A \Rightarrow i + e = 45^\circ + 60^\circ = 105^\circ$ .
By reversibility, the two angles of incidence giving the same $\delta$ are $i$ and $e$ : $i_1 + i_2 = 105^\circ$ .
$i_1 - i_2 = 20^\circ \Rightarrow i_1 = 62.5^\circ,\ i_2 = 42.5^\circ$
So the answer is (a) $62.5^\circ$ .

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Prism, Dispersion & Scattering question from MHT CET 2026 (14 May, Shift 2)

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