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JEE Main 2021 (16 Mar, Shift 1) · Prism, Dispersion & Scattering

Prism, Dispersion & Scattering question from JEE Main 2021 (16 Mar, Shift 1)

Q56JEE Main 2021 · 16 MAR · SHIFT 1Easy

Prism, Dispersion & Scattering

The angle of deviation through a prism is minimum when

Figure

(A) Incident ray and emergent ray are symmetric to the prism.

(B) The refracted ray inside the prism becomes parallel to its base

(C) Angle of incidence is equal to that of the angle of emergence

(D) When angle of emergence is double the angle of incidence

Choose the correct answer from the options given below:

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Answer: (c)

  1. At minimum deviation r1=r2r_1 = r_2, so the ray inside is parallel to the base: (B) true.
  2. Then i=ei = e: (C) true, and the incident and emergent rays are symmetric about the prism: (A) true.
  3. (D) is false, e=ie = i, not 2i2i.
  4. So the answer is (c) A, B and C are true.
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