Question

An object is placed on the principal axis of a concave lens at a distance of 20cm from it if the focal length of the lens is also 20 cm find the location of the image.​

Answer 1

Given:-

• Focal Length (f) = -20cm

• Object Distance (u) = -20cm

To Find:-

• Location of the image

Solution:-

By using Lens Formula

⟹ 1/v - 1/u = 1/f

⟹ 1/v = 1/u - 1/f

Put the value,we get

⟹ 1/v = 1/(-20) - 1/20

⟹ 1/v = -1/10

⟹ v = -10cm

∴ Thus , the image is formed at a distance of 10 cm from the lens.

Answer 2

Answer:

GIVEN:

f = - 20 cm

u = - 20 cm

TO FIND:

The location of the image

Explanation:

SOLUTION:

Lens formula = 1/v = 1/u - 1/f

= u+f/uf

= uf/u+f

(-20)(-20)

= ---------------

(-20)+(-20)

= 400

---------

-40

V = -10

Therefore, the image will formed at a distance of 10cm from the lens.