Question

focal length of concave lens is 30 centimetre find the position of image of an object which is kept 15 CM in front of lens and draw a ray diagram

Answer 1

Answer:

u = -60cm

Explanation:

Given: Focal length, f=−20cm               

 Image distance,  v=−15cm (concave mirror)

To find: Object distance, u

From lens

1/v - 1/u = 1/f

1/−15 - 1/u = -1/20

1/20 − 1/15 = 1/u

u=−60cm