Question

a concave lens of focal length 20cm forms an image 10cm from the lens the height of the object is 4 cm calculate the object distance and the nature size and magnification of the image formed draw a diagram to show the formation of image in above situation

Answer 1

Answer:

Given f = - 20 cm, (sign convention) , v = - 10 cm

(∴ image formed by concave lens is virtual)

By using lens formula,

or u = - 20

Thus the object is placed at 20 cm from the concave lens