Question

a concave lens has a focal length 15cm it forms an image at distance of 10cm from the lens find distance of object from lens​

Answer 1

Answer:

Given:-

Focal length of the concave lens= -15cm

Image distance from the concave lens= -10cm

By using lens formula, we have

1/f=1/v-1/u

1/u=1/v-1/f

1/u=1/(-10) - 1/(-15)

1/u= -5/150

u= -150/5 = -30cm

The object distance from the concave lens= -30

There for the object is placed at 30cm from the concave lens.