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.

Q. 11 : – 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. 

 

Answer:-

Focal length f = − 15 cm
Image-distance v = − 10 cm
object-distance u = ?

Q11-Light–Reflection-and-Refraction-Science-CBSE-Class-10

 

1 1 1


=
v u f
1 1 1


=
− 10 u − 15
− 1 1 1

+
=
10 15 u
=> 1 − 3 + 2

=
u 30
=> u = − 30 cm

Object is placed at a distance of 30 cm from concave lens