A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image is

Options

A. virtual and at a distance of `16cm`from the mirror.
B. Real and a distacne of`16cm`from the mirrors
C. virtual and a distance of `20cm`from the mirror
D. real and at a distanceof `20cm` from the mirrror

Answer

B

Explanation

First image`(1)/(v)-(1)/(u)=(1)/(f),(1)/(v)-(1)/(-30)=(1)/(15)`
`v=30`,image is formed `20cm`behind the mirror.
=Second image ,by plane mirror will be at`20cm`infont of plane mirror.
For third image,`(1)/(v)-(1)/(10)=(1)/(15)`
`(1)/(v)-(1)/(10)+(1)/(15)=(3+2)/(30)=(5)/(30)`
final image is real and formed at a distance of `16cm`from mirror.