Question

(CBSE 2018)
10. An object is placed at a distance of 15 cm from a concave lens of focal length 30 cm
List four characteristic nature, position, etc.) of the image formed by the lens.
(CBSE 2017)​

Answer 1

Answer:

virtual and erect , diminished ,at -10 cm image is formed from the lens,

Answer 2

Answer:

Given :

Object distance u = 30 cm

Focal length = 15 cm .

Since it's concave lens.

= > u = - 30 and f = - 15 cm

We have lens formula :

1 / f = 1 / v - 1 / u

1 / v = 1 / f + 1 / u

1 / v = - 1 / 15 - 1 / 30

1 / v = - 1 / 10

v = - 10 cm .

Now nature of image is as :

( i )  Image is formed on the left side of the lens.

( ii ) The image is virtual and erect.