Question

A doctor has prescribed a corrective lens of power +1.5D. What is the focal length of the lens? Is the lens diverging or converging? Draw ray diagram

Answer 1

Answer:

Given, power of lens ,P = +1.5D

It means the lens is convex

As power, P = 1/f (in m)

so, f = 1/P

= 1/1.5

= 10/15

= 0.66m

f = 0.66 × 100

= 66cm

{It is converging lens because it's focal length is positive}