Notifications
Clear all
The Human Eye and Colourful World
1
Posts
2
Users
0
Likes
407
Views
0
28/08/2021 7:01 pm
Topic starter
A person needs a lens of power, -5.5 dioptres for correcting his distant vision. For correcting his near vision, he needs a lens of power, +1.5 dioptres. What is the focal length of the lens required for correcting
1. distant vision, and
2. near vision?
1 Answer
0
28/08/2021 7:03 pm
1. For distant vision:
P = -5.5D
P = \(\frac{1}{f}\)
f = \(\frac{1}{P}\) = \(\frac{1}{-5.5}\) = -0.1818 m
= -18.18cm
2. For Near Vision:
P = 1.5D
P = \(\frac{1}{f}\)
f = \(\frac{1}{P}\) = \(\frac{1}{1.5}\) = 0.6666
= 66.66 cm