A convex lens has its radii of curvature equal. The focal length of the lens is f. If it is divided vertically into two identical plano-convex lenses by cutting it, then the focal length of the plano-convex lens (p = the refractive index of the material of the lens)

Options

A. f
B. `f/2`
C. 2f
D. `(mu-1)f`

Answer

C

Explanation

If a lens is vertically divided into two parts then, the power becomes half.
`therefore` The focal length becomes 2f.