Author Question: What power contact lens must be used to correct the vision of a nearsighted person whose far point ... (Read 87 times)

ts19998 · **on:** Jul 29, 2018

What power contact lens must be used to correct the vision of a nearsighted person whose far point is 40 cm?

A) 2.5 diopters
B) -2.5 diopters
C) -3.6 diopters
D) -4.0 diopters
E) 4.0 diopters

Question 2

The focal length of a thin lens is 40 mm and its aperture diameter is 10 mm. What is the f-number of this lens?

A) f/4.0
B) f/2.0
C) f/5.6
D) f/0.30
E) f/0.40