#### Question

An object is placed at a distance of 100 cm from a converging lens of focal length 40 cm.

(i) What is the nature of image?

(ii) What is the position of image?

#### Solution

Given:

Object distance, *u *=-100 cm

Focal length, *f* = 40 cm

Applying lens formula, we get:

1/*v-*1/*u *= 1/*f*

1/*v-* 1/(-100) = 1/40

or, 1/v = 1/40 - 1/100

or, 1/v = 6/400

or, 1/v = 3/200

or, *v* = 200/3 = +66.6 cm

Now

Magnification, *m* = *v*/*u**m*= (200/3)/(-100)*m=-*2/3

(i) The value of magnification is negative, therefore, the image will be real and inverted.

(ii) The value of *v *is (+66.6 cm); therefore, the image is formed 66.6 cm behind the convex lens.

Is there an error in this question or solution?

Solution An Object is Placed at a Distance of 100 Cm from a Converging Lens of Focal Length 40 Cm. (I) What is the Nature of Image? (Ii) What is the Position of Image? Concept: Mirror Formula and Magnification.