Question

12. A concave lens of focal length 20 cm
forms an image at a distance of 10 cm
from the lens. What is the distance of the
object from the lens? *​

Answer 1

The lens is concave lens.

f=20cm

u=?

v=10 cm

By using formula ,

1/f=1/u+1/v

1/20=1/u+1/10

1/u=1/20-1/10

=0.2-0.1

=0.1=1/10

u=1/10