Question

A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?

Answer 1

Power of lens,

P = +1.5 D,

P = `1/"f"`

f = `1/"P"`

= `1/(+1.5  "D")`

= +0.67 m 

A convex lens has a positive focal length. Hence, it is a convex lens or a converging lens.