Extra Questions for Module 6
Nominal Power formula, Surface Power formula, Lensmaker's
formula.
Each worksheet is different, because each one was originally written by
a different person. Use the directions at the beginning of each worksheet
for that worksheet.
Radius of Curvature Worksheet
Calculate the dioptric power of the following. Round diopters
to two decimal places. (Not to 1/8 diopter steps)
Index
-
1.523
-
1.523
-
1.530
-
1.70
-
1.530
-
1.498
|
Radius in mm
+209
-68
+84
-84
+49
+49
|
Diopters
________
________
________
________
________
________
|
Calculate the radius of curvature for the following. Round to
whole mm.
Index
-
1.530
-
1.530
-
1.523
-
1.60
-
1.50
-
1.70
|
Radius in mm
________
________
________
________
________
________
|
Diopters
+5.00
-1.25
-8.50
+11.37
-20.00
+20.00
|
Radius of Curvature Worksheet
-
What is the dioptric power of a crown glass surface if it has a radius
of curvature of 135 cm?
D = ?
n = 1.523
r = 135 cm
= ? meters
-
What is the dioptric power of a CR39 surface if it has a radius of curvature
of 35 mm?
D = ?
n = 1.498
r = 35 mm
= ? meters
-
What is the radius of curvature in millimeters of a +6.00D crown glass
surface?
D =
n =
r = ? meters
= ? mm
-
What is the radius of curvature in cm of a +2.50D CR39 surface?
D =
n =
r =
=
-
What is the radius of curvature in mm of a +6.00D polycarbonate surface?
D =
n =
r =
=
Nominal Power Formula
-
Find the nominal power (DN) if:
-
D1 = +10.00 and D2 = -6.00
-
D1 = +2.00 and D2 = -4.50
-
D1 = +8.00 and D2 = -5.75
-
D1 = -1.25 and D2 = -3.75
-
D1 = -5.00 and D2 = -6.00
-
-
Find the back surface (D2) if:
-
DN = +10.00 and D1 = +6.00
-
DN = +2.00 and D1 = +8.50
-
DN = +8.00 and D1 = +5.75
-
DN = -5.00 and D1 = -1.00
-
DN = +6.50 and D1 = +10.00
-
DN = -6.50 and D1 = +0.50
-
-
Find the front surface (D1) if:
-
DN = +10.00 and D2 = -2.00
-
DN = +2.00 and D2 = -8.50
-
DN = +8.00 and D2 = -2.75
-
DN = -1.25 and D2 = -7.75
-
DN = -5.00 and D2 = -3.00
-
DN = +6.50 and D2 = -10.00
-
-
I need a lens with power +3.50D. If I use a lens blank with a front
surface power of +8.00D, what back surface do I need?
-
I have a lens with a front surface of +9.25D and a back surface of -2.25D.
What is the power of the lens?
-
I want my lens to have a power of -3.00D. What back surface do I
need if the front surface is +8.00D?
Lensmakers Equation Worksheet
-
A plastic meniscus lens of index 1.50 has a front radius of curvature of
8 cm and a back radius of curvature of 22.22 cm. What is its dioptric
power? [In this worksheet, meniscus means one surface is + and
one is -]
-
A barium meniscus lens, n = 1.60, has a front radius of curvature of 12
cm and a back radius of curvature of 7.5 cm. What is its dioptric
power?
-
A flint meniscus lens, n = 1.70. has a front radius of curvature of 11.2
cm and a back radius of curvature of 175 mm. What is its dioptric
power?
-
What is the power of a plano-convex polycarbonate lens with a front surface
radius of curvature of 500 mm? [Plano-convex means one surface
is plano, 0 power, and one surface is convex, + power.]
-
What is the power of a plano-concave crown glass lens with a back surface
radius of curvature of 45 mm? [One surface 0, one surface -.]
-
What is the power of a biconvex high-lite (n = 1.70) lens with a front
surface radius of curvature of 70 cm and a back surface radius of curvature
of 1.5 m? [Both surfaces +.]
-
What is the power of a biconcave CR39 lens with a front surface radius
of curvature of 250 mm and a back surface radius of curvature of 37.5 cm?
[Both
surfaces -.]
The answers are here. Please
do them yourself before you go to the answers. If you understand
it all and you don't need the practice then it will only take you a few
minutes to do them. If you are struggling with the formulas do one
or two, check them, do a few more, check them, . . . just make sure that
you do not look ahead of the ones that you did and are checking.
Press the BACK button at the top left of the screen to return
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