Question

A 4 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find the nature, position and the size of the image formed.

Answer 1

Given, u = - 15 cm, f = 20 cm, v=?

Using lens formula, 1/v- 1/u= 1/f  

1/v = - 1/60

V = -60 cm

m = hi/ho= v/u

hi = 16 cm

Image formed is virtual, erect and magnified.