JEE Advanced2026PhysicsRay OpticsActual
Consider two isosceles prisms 1 and 2 with prism angles A₁ and A₂ and refractive indices n₁ and n₂ , respectively, as shown in the figure. The faces a₁ b₁ and a₂ b₂ are parallel to each other and perpendicular to the mirror M . If a ray of light is incident on the face a₁ c₁ and emerges from the face a₂ c₂ , then the correct statement(s) is/are:
Options
- AIf both the prisms are at minimum deviation condition, then n₂ n₁ = ( A₁ 2 ) / ( A₂ 2 ) .
- BIf prism 2 is at minimum deviation condition, then i₁ = n₂ ( A₂ 2 ) is always true.
- CIf both the prisms 1 and 2 are thin and are at minimum deviation condition with angles of deviation _ m1 and _
- DIf prism 1 is at minimum deviation condition, then i₂ = n₁ ( A₁ 2 ) is always true.
Correct answer
A. If both the prisms are at minimum deviation condition, then n₂ n₁ = ( A₁ 2 ) / ( A₂ 2 ) .
Step-by-step solution
From the given geometry, faces a₁b₁ and a₂b₂ are parallel to each other and perpendicular to the horizontal mirror M . Thus, a₁b₁ and a₂b₂ are vertical. The normal to a₁b₁ is horizontal. The ray emerging from Prism 1 makes an angle e₁ with this horizontal normal. By the law of reflection at mirror M , the reflected ray also makes an angle e₁ with the horizontal. This reflected ray is incident on the vertical face a₂b₂ of Prism 2. The normal to a₂b₂ is horizontal, so the angle of incidence is i₂ = e₁ . Evaluating op