Question

define and derive the lens maker formula.....

Answer 1

The lens is thin, so that distances measured from the poles of its surfaces can be taken as equal to the distances from the optical centre of the lens.The aperture of the lens is small.Point object is considered.Incident and refracted rays make small angles.

Consider a convex lens (or concave lens) of absolute refractive index m2 to be placed in a rarer medium of absolute refractive index m1.

Answer 2

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The focal length of a lens depends upon the refractive index of the material of the lens and the radii of curvatures of the two surfaces. ... The derivation of lens maker formula is provided here so that aspirants can understand the concept more effectively.

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