PASCO OS-8536 OPTICS TABLE - Manual (Page 12)

8
Optics Table 012-06557A
Experiment 4: Reflection – Plane and Curved Mirrors
EQUIPMENT NEEDED
– Light Source – Optics Bench
– Three-Surface Mirror – Drawing compass (SE-8733)
– metric rule – pencil
Purpose
To study how rays are reflected and to determine the focal
length and radius of curvature of different types of mirrors.
Part I: Plane Mirror
Procedure
Mount the Light Source and the Ray Table Base on the Op-
tics Bench. Put the Ray Table on the base with the DEGREE
SCALE facing up. Position the Light Source near the edge of
the Ray Table. Adjust the slit mask on the Light Source so
one light ray shines across the middle of the top of the Ray
Table. Rotate the table so the light ray shines along the NORMAL line on the table.
Place the Three-Surface mirror on the COMPONENT line on the Ray Table with the plane surface facing the
light source.
Rotate the Ray Table a few degrees. Measure the angle of incidence (
θ
i
) and the angle of reflection. Both these
angles should be measured from the NORMAL line.
Change the angle of incidence and measure the incident and reflected angles again.
Part II: Cylindrical Mirrors
T heor y
A concave cylindrical mirror will focus parallel rays of light at a focal point. The focal length is the distance
from the focal point to the center of the mirror surface. The radius of curvature of the mirror is twice the focal
length. See the diagram.
P roced ure
Adjust the slit mask on the front of the Light Source so that five
light rays from the Light Source shine across the top of the Ray
Table. Rotate the table so the center light ray shines along the
NORMAL line. Turn the Three-Surface mirror so the concave
surface faces the Light Source and the center light ray shines on
the center of the curved surface.
Trace the outline of the mirror and trace the incident and reflected
rays. Indicate the incoming and the outgoing rays with arrows in
the appropriate directions.
P
A
TTERN
LIGHT
SOURCE
COLOR
BULB
: 12V
10W G-4
DO NOT
T
O UCH BULB
WI
TH
FINGERS.
DISCONNECT
PO
WE
R
BEFORE CHAN
GING BULB
. 5 3 1
RA
Y
SLITS
Figure 4.1
Incident Ray
Normal to surface
θ
i
Figure 4.2
P
A TTERN
SOURCE
COLOR
DISCONNECT
PO
WE
R
BEFORE CHAN
GING BULB
. 5 3 1
RA
Y
SLITS