Question

The focal length of a converging lens is 20cm. An object is 60cm from the lens. Where will be image be formed and write characteristics of the image.

Answer 1

Focal length = f = 20 cm (+ 20cm) 

Object distance = u = 60 cm (- 60cm) 

Image distance = v = ?

Here, (-) indicates inverted images.

m = 1/2 < 1 indicates diminished image. Image forms between F₁ and 2F₁. 

Characteristics of the image :

1. real 

2. inverted 

3. diminished.

Answer 2

Focal length = distance between focus and center of curvature =20 cm

Since 2F=40 cm

It is given that object is kept at 60 cm from center of curvature since object is beyond 2F.

Nature of image → Real and inverted

Size of image → Smaller

Position → Between F and 2F on other side of lens.