A convex lens is made up of three different materials as shown in the figure. For a point object placed on its axis, the number of images formed are

Options

A. 5
B. 1
C. 3
D. 4

Answer

C

Explanation

Focal length of a convex lens is given by
`(1)/(f)=(mu-1)((1)/(R_(1))-(1)/(R_(2)))`
As the lens is made up of three different materials (having three different refractive indices, `mu`), it has three different focal lengths. So for a point object placed on the axis, it will form three images according to the formula
`(1)/(v)-(1)/(u)=(1)/(f)`.