Question

a diverging lens focal length 20 cm is used at what distance short be placed to form image at 15cm give magnification​

Answer 1

Answer:

Explanation a diverging lens is a concave lens

f= -20cm

v= -15cm

u=?

by using

1/v -1/u =1/f

-1/15-1/u =-1/20

-1/u =-1/20+1/15

-1/u=1/60

u=-60 cm

∴object should be placed at a distance of 60cm

m=v/u

=-15/-60

=1/4