Biomedical Engineering Reference
In-Depth Information
Magnification for a mirror:
−
′
l
M
L
=
l
Fraction of light reflected off a refractive surface:
2
n
−
n
′
⎥
⎣
Index of coating needed to minimize reflections:
n
c
⎥
⎦
R
=
n
+
n
′
√
n
L
=
SELF-ASSESSMENT PROBLEMS
1. An object is located 5.00 cm anterior to a concave mirror that has a radius of
curvature of 30.00 cm. (a) Locate the image. (b) Is the image real or virtual?
(c) If the object is 2.00 cm in height, what is the height of the image?
2. For the mirror in Problem 1, the object is located at a distance of 20.00 cm.
(a) Locate the image. (b) Is the image real or virtual? (c) If the object is 2.00 cm
in height, what is the height of the image?
3. An object is located 25.00 cm anterior to a convex mirror that has a focal length
of
15.00 cm. (a) Locate the image. (b) Is the image real or virtual? (c) If the
object is 2.00 cm in height, what is the height of the image?
4. A real image is located 40.00 cm from a
+
30.00 D mirror. Locate the object.
5. A virtual image is located 10.00 cm from a −30.00 D mirror. Locate the object.
6. An object is located 20.00 cm anterior to a
+
15.00 D lens. This lens is located
3.00 cm anterior to a mirror that has a radius of curvature of
+
2.00 cm. (a) Locate
the image. (b) What is the magnification of the optical system?
7. A light is located 10.00 cm anterior to the cornea of the eye. Assuming that the
anterior surface of the cornea has a radius of 7.80 mm, locate the first Purkinje
image.
8. A circular light is located 7.00 cm anterior to the cornea of the eye. If the first
Purkinje image is oval in shape with its long axis vertical, is the corneal toricity
with-the-rule or against-the-rule?
9. (a) What percentage of light is reflected by the front surface of a lens that is
made from a high-index plastic material (
n
+
1.74)? (b) Answer the same question
for a CR-39 lens. (c) For which lens would an antireflection coating be most
important? Why? (d) What should be the index of refraction of the antireflection
coating for the higher-index lens?
=
