Question

Power of lebs is 0.4D.what is its focal length

Answer 1

Hey there!

Given,

Power of lens = 0.4 D

We know,

Power of lens = 1 / focal length

0.4 = 1 / f

1 / 0.4 = f

2.5 = f

or, f = 2.5 m

Hope It Helps You!