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MHT CET 2025 (21 Apr, Shift 2) · Refraction, Glass Slab & Apparent Depth

Refraction, Glass Slab & Apparent Depth question from MHT CET 2025 (21 Apr, Shift 2)

Q12MHT CET 2025 · 21 APR · SHIFT 2Medium

Refraction, Glass Slab & Apparent Depth

A ray of light travelling through rarer medium is incident at a very small angle ' ii ' on a glass slab and after refraction its velocity is reduced by 20%20\%. The angle of deviation is

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Answer: (a)

  1. Speed drops by 20%20\%: v=0.8c⇒μ=cv=1.25v = 0.8c \Rightarrow \mu = \dfrac{c}{v} = 1.25.
  2. For small angles i=μr⇒r=i1.25=0.8ii = \mu r \Rightarrow r = \dfrac{i}{1.25} = 0.8i.
  3. Deviation δ=i−r=0.2i=i5\delta = i - r = 0.2i = \dfrac{i}{5}.
  4. So the answer is (a).
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