Question

derivation of lens makers formula.....please answer in easy way??

Answer 1

Consider the thin lens shown here with the two refracting surfaces having radii of curvature equal to R1and R2respectively.

The refractive indices of this surrounding medium and of the material of the lens are n1 and n2 respectively.

Now using the result that we obtained for refraction at single spherical surface we get,

For first surface,
 . . . (1)

For second surface,
 . . . (2)
Adding (1) and (2),

When u = ∞ , v = f

Also,1/v - 1/u = 1/f