Question

Ek utal lens ki shamta + 5 D hai to uski fokas duri kitni hogi?

Answer 1

Power of a lens is determined by the formula P=1/f (when focal length is in meters) and P=100/f (when focal length is in centimeters) Here,the power is given as 5 diopters. On equating we get, ⇒5=100/f ⇒f=100/5 =20 cms.