Question

A convex lens has focal length +20cm,it's power is...........
​

Answer 1

Answer:

power is reciprocal of Focal length.

f=+20cm

p =1/f

p= 1/20= 0.05

unit of power is dioptre.

so answer is +0.05d

hope it helps you

please mark the brainliest

Answer 2

Explanation:

power=1/f in meters and 100/f in centi meters

now u can take 100/f in cm because the focal length value is in cm..

100/f = (f =20cm)

therefore ...the power of the lens is 5D

D means diopter