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?

Q. 17 :- 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:-

Power of lens, P = + 1.5 D

1
P =
f
1
1.5 =
f
1
f =
m
1.5
10
f =
m
15
10
f =
m
15
2
f =
m = + 0.67 m
3

Focal length of the lens is + 0.67 m. The prescribed lens is converging type in nature.