Question

An object of size 5 cm is kept at a distance of 25 cm from the optical centre of a converging lens of focal length 10 cm. Calculate the distance of image from the length and the size of the image?

Answer 1

Lens formula is : 1/v - 1/u = 1/f So, 1/v - 1/(-25) = 1/10 1/v =1/10 - 1/25 1/v = 15/250 1/v = 3/50 v = 50/3 cm Magnification = v/u = (50/3) / (-25) = -2/3 {- ve sign indicates that image will be inverted} size of image = size of object x magnification = 5 x 2/3 = 10/3 cm = 3.33 cm