A 1 cm object is placed perpendicular to the principal axis of a convex mirror of focal length 7.5 cm. Find its distance from the mirror if the image formed is 0.6 cm in size.

Answer

C

Explanation

`mu=-v/u=0.6 and f=7.5 cm=15/2cm`
`From mirror equation
`1/v+1/u=1/f`
`=1/(0.6u)-1/u=1/f`
`rarr 5/(3u)-1/u=1/f`
`rarr 5/(3u)+1/u=2/15`
`rarr =5cm`