Question

An object is placed 12 cm from a convex lens . Its image is formed on the other side of lens at a distance of 18 cm from the lens.Focal length of the lens will be​

Answer 1

Focal length of convex lens, f=8 cm

Object distance, u=−12 cm

Using lens formula

v

1

−

u

1

=

f

1

where v is the image distance.

∴

v

1

−

−12

1

=

8

1

⟹ v=+24 cm

(+ve sign indicates that image is formed behind the lens)

Hence the image formed is real and inverted.

I hope this will be helpful