Question

a concave lens of focal length 15cm form on image 10cm from the lens. How far is the object placed from the lens?​

Answer 1

object distance,u=?

focal length of concave lens=15cm

image distance,v=10

formula=1/v-1/u=1/f

=1/10-1/u=1/15

=1/u=1/15+1/10

=1/u=2+3/30

=1/u=5/30

=1/u=6

object distance is 6cm

Answer 2

Answer:

20 cm far place the lease