Question

A object is at 10cm from the convex lens. if the focal length is 40cm then determine the position and nature of the image​

Answer 1

Explanation:

Given:u=−10cm f=20cm (convex lens)

To find: v and image's nature.

Solution: From lens formula

1/f= 1/v-1/u

1/v= 1/f+1/u

= 1/40+(-1/10)

= 1/40-1/10

= 1/40-4/40

= -3/40= 1/v

v= -40/3 or 13.33 cm

m= v/u

= -13. 33/-10

= 1.3

the image formed is virtual and erect and behind the lens