Question

Write the lens makers formula and name the terms in it.

Answer 1

1/f=(n-1)(1/R1-1/R2)

Answer 2

For first surface,

. . . (1)

For second surface,

. . . (2)

Adding (1) and (2),

When u = ∞ , v = f

Also,

A lens is converging if its focal length is positive and diverging if focal length is negative (in cartesian sign convension). From this we can conclude that a convex lens need not necessarily be a converging and a concave lens diverging