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MHT CET 2026 (16 Apr, Shift 2) · Refraction, Glass Slab & Apparent Depth

Refraction, Glass Slab & Apparent Depth question from MHT CET 2026 (16 Apr, Shift 2)

Q5MHT CET 2026 · 16 APR · SHIFT 2Medium

Refraction, Glass Slab & Apparent Depth

A ray of light passes from the vacuum into a medium of refractive index 'n'. If the angle of incidence is twice the angle of refraction, then the angle of incidence in terms of refractive index is

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Answer: (b)

  1. Snell's law with i=2ri = 2r: n=sin⁡2rsin⁡r=2sin⁡rcos⁡rsin⁡r=2cos⁡rn = \dfrac{\sin 2r}{\sin r} = \dfrac{2\sin r\cos r}{\sin r} = 2\cos r.
  2. cos⁡r=n2⇒r=cos⁡−1(n2)\cos r = \dfrac{n}{2} \Rightarrow r = \cos^{-1}\left(\dfrac{n}{2}\right).
  3. i=2r=2cos⁡−1(n2)i = 2r = 2\cos^{-1}\left(\dfrac{n}{2}\right).
  4. So the answer is (b).
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