A 5.0 diopter lens forms a virtual image which is 4 times the object placed perpendicularly on the principal axis of the lens. Find the distance of the object from the lens.

given that power of lens, P= 5 diopter

Focal length of the lens= 1/5= 20cm

Magnification of the object, m= 4

Using lens formula,

Hence, the required object distance =15cm