Question

an eye specialist prescribes a number 4.5d to a person fir his glasses what is the nature of the lens ? what is the focal length of the lens?

Answer 1

Explanation:

Mate your answer is

The nature of the lens prescribed is "converging" or "convex lens", as P=+ve.

As, P=1/f

=>f=1/P

=1/4.5

=10/45

=2/9

f=0.22m

OR f=22.22cm