Question

If the power of a convex lens is 5 D. then what is it's focal length in cm?​

Answer 1

Answer:

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.