A converging lens of focal length 15 cm and a converging mirror of focal length 10 cm are placed 50 cm apart with common principal axis. A point source is placed in between the lens and the mirror at a distance of 40 cm from the lens. Find the locations of the two images formed.

Explanation

Directly by lens:
`u=-40cm,f=15cm,v=?`
`(1)/(v)-(1)/(u)=(1)/(f)implies(1)/(v)-(1)/(-40)=(1)/(15)`
`(1)/(v)=(1)/(15)-(1)/(40)=(8-3)/(120)=(5)/(20)`
`v=24cm`
By mirror and lens:
By mirror image is formed at infinite because object is at focus of mirror.
By lens image is formed at focus of lens.