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MHT CET 2023 (13 May, Shift 2) · Spherical Surfaces & Thin Lenses

Spherical Surfaces & Thin Lenses question from MHT CET 2023 (13 May, Shift 2)

Q56MHT CET 2023 · 13 MAY · SHIFT 2Medium

Spherical Surfaces & Thin Lenses

The radii of curvature of both the surfaces of a convex lens of focal length ff and power PP are equal. One of the surfaces is made by plane grinding. The new focal length and focal power of the lens is

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Answer: (d)

  1. Equiconvex: 1f=(μ−1)2R\frac{1}{f} = (\mu - 1)\frac{2}{R}.
  2. After grinding one face plane: 1f′=(μ−1)1R=12f\frac{1}{f'} = (\mu - 1)\frac{1}{R} = \frac{1}{2f}.
  3. So the answer is (d) 2f, P22f,\ \frac{P}{2}.
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