Question

A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram also. ​

Answer 1

Explanation:

hope , you will understand

Answer 2

Answer:

Qin this question we have to calculate the object distance u

Explanation:

image distance v=-10 cm

focal length f =-15 cm

now putting these values in the lens formula:

1/v-1/u=1/f

we get

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

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

-1/u=(-2+3)/30

-1/u=1/30

object distance,u=-30 cm

thus the object placed at distance of 30 cm from the concave lens. the minus sign with object distance shows that the object is on its left side.

hope this will help you