Question

An object is placed at a distance of 10 cm from a convex lens of focal length 12 cm, find out at what distance image will be formed from the lens and what is the nature of image.

Answer 1

Given: Focal length (f) = 12 cm,

Object distance (u) = −10 cm

To find: i. Image distance (v)

ii. Nature of image

Formula: `1/"f" = 1/"v" - 1/"u"`

Calculation: From formula,

`1/12 = 1/"v" - 1/(- 10)`

∴ `1/"v" = 1/12 - 1/10`

`= (10 - 12)/120`

`= (- 2)/120`

`= - 1/60`

∴ v = - 60 cm

A negative sign indicates an image is formed on the same side as that of the object.

The image is erect, virtual and magnified.