Question

A concave lens has a focal length of 20 cm. At what distance from the lens, a 5 cm tall object is placed so that it forms an image at 15 cm from the lens? plz

Answer 1

$1/f = 1/v-1/u$

$1/(-20) - 1/-15= - 1/u$

$(15-20)/300 = - 1/u$

$1/u = - 5/300$

$u = - 60 cm$

$hi/ho= v/u$

$hi/5 = -15/-60$

$hi=5/4 cm=1.25 cm$

$PLZ MARK IT AS BRAINLIEST$