Q1: Using
the thin lens formulas, show that when M = + 1 / 2 for a diverging
lens; d
i
= - d
o
/ 2; and f = - d
o
. Attach your proof to the sheet, together with a rough
ray sketch of this situation (show focal, parallel and chief
rays).
Q2:
Determine do for four separate eyeglass lenses. Use
the relationship Power (in diopters) = 1 / f (in meters) to determine
the eyeglass prescription in diopters.
As an example: if d
o
= 33 cm; P = -3.3D. Write the focal length and diopter equivalence
for your four lenses on the sheet.
Q3:
What would be the focal length of a -1.75D and a -1.25D lens?
Q4:
How would a +1.75D lens differ from a -1.75D lens?
Q5: How
would an optometrist characterize the vision of a person with
these prescriptions?
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