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The refractive index of a converging lens is 1 . 4 . What will be the focal length of this lens if it is placed in a medium of same refractive index ? (Assume the radii of curvature of the faces of lens are R 1 and R 2 respectively)

Options

  1. A1
  2. BInfinite
  3. CR 1 R 2 R 1 - R 2
  4. DZero

Correct answer

B. Infinite

Step-by-step solution

1   F = μ L μ S - 1 1 R 1 - 1 R 2 If μ L = μ S ⇒ 1   F = 0 ⇒ F = ∞

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