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Focal length of a convex lens will be maximum for

Options

  1. Ayellow light
  2. Bgreen light
  3. Cred light
  4. Dblue light

Correct answer

C. red light

Step-by-step solution

By lens Maker's formula, focal length of lens is given as 1 f =( -1) ( 1 R₁ - 1 R₂ ) where, is refractive index. 1 f ( -1) f 1 ( -1) Since, 1 From Eqs. (i) and (ii), we get f But, wavelength of red colour of light is maximum as all the other constituent colours of white light. Hence, focal length of a convex lens is maximum for red light.

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