PASCO OS-8500 INTRODUCTORY OPTICS SYSTEM - Manual (Page 21)

012-02744K Introductory Optics System
®
15
Experiment 5: Reversibility
Figure 5.2 Internal Angle of Incidence
Equipment Needed:
-Optics Bench -Light Source
-Ray Table and Base -Component Holder
-Slit Plate -Slit Mask
-Cylindrical Lens.
Figure 5.1 Equipment Setup
Introduction
In Experiment 4, you determined the relationship
that exists between the angle of incidence and the
angle of refraction for light passing from air into a
more optically dense medium (the Cylindrical Lens).
An important question remains. Does the same
relationship hold between the angles of incidence
and refraction for light passing out of a more
optically dense medium back into air? That is to
say, if the light is traveling in the opposite direction,
is the law of refraction the same or different? In
this experiment, you will find the answer to this
question.
Procedure
Set up the equipment as shown in Figure 5.1.
Adjust the components so a single ray of light
passes directly through the center of the Ray Table
Degree Scale. Align the flat surface of the Cylin-
drical Lens with the line labeled “Component”. With the lens properly aligned, the radial lines
extending from the center of the Degree Scale will all be perpendicular to the circular surface of the
lens.
Without disturbing the alignment of the lens, rotate the Ray Table and set the angle of incidence to
the values listed in Table 5.1 on the following page. Enter the corresponding angles of Refraction in
the table in two columns: Refraction
1
and Incidence
2
. (Let Incidence
2
= Refraction
1
).
Slit Plate
Slit Mask
90 80 70 60
50
40
30
20
1 0
0
0
10
20
3 0
4 0
50
60
70
80
90 80 70 60
50
40
30
20
1 0
10
20
3 0
4 0
50
60
70
80
NOR MAL
NOR MAL
C O M P O N E N T
C O M P O N E N T
Incidence
1
Refraction
1
90 80 70 60
50
40
30
20
10
0
0
10
20
30
4 0
5 0
60
70
80
90 80 70 60
50
40
30
20
10
10
20
30
4 0
5 0
60
70
80
NORMAL
NORMAL
COMPONENT
COMPONENT
Angle of
Refraction
(Incidence
2
)
(Refraction
2
)
Internal Angle
of Incidence