Question

A concave lens of focal length 60 cm is used to form an image of an object of length 9 cm kept at a distance of 30 cm from it use lens formula to determine the nature , position , and length of the image formed . Also draw labelled diagram to show the image formation.



Anyone please solve this question please

No Spam please ​

Answer 1

Explanation:

Focal length of concave lens, f = -60 cm

distance of object from the concave lens, u = -30

Use lens formula,

1/v -1/u = 1/f

or, 1/v -1/60 = 1/-30

or, 1/v = 1/-60 + 1/-30 =1/-60 +2/-60

or,1/v 3/-60 = 1/-20 => v = 20 cm

hence, v = 20 cm

now, magnification, m = v/u

or,m = (-20)/(-30) = 2/3 = length of image/length of object

2/3 = length of image/ 9 cm

length of image = 6 cm

hence, nature of image is virtual and diminished, image is placed between objects and lens and length of image is 6cm.

Answer 2

(i) Use the lens formula to find the distance of the image from the lens. (ii) List four characteristics of the image (nature, position, size, erect/inverted) ...