Question

An object is placed at a distance of 10 cm on the principal axis of a convex lens whose focal length is less than 10 cm, then the image of it observed at a distance of 30 cm from the lens. Find the nature and magnification of image.​

Answer 1

Answer:

Given:u=−10cm               f=20cm        (convex lens)

To find: v and image's nature.

Solution: From lens formula

v1−u1=f1

v1+101=201

v1=20−1

v=−20cm

And magnification = uv=2

Hence image formed is virtual, erect and magnified two times.