PASCO OS-8536 OPTICS TABLE - Manual (Page 11)

7
012-06557A Optics Table
Experiment 3: Prism
EQUIPMENT NEEDED
– Light Source – Optics Bench
– Ray Table and Base – Rhombus
– white paper
Purpose
To show how a prism separates white light into its component colors and to show that different colors are re-
fracted at different angles through a prism.
Theory
Snell’s Law states that the angle of refraction depends on the angle of incidence and the index of refraction of
the material. Because the index of refraction for light varies with the frequency of the light, white light which
enters the material at a given angle of incidence will separate out into its component colors as each frequency is
bent a different amount.
Procedure for Separating White Light
Mount the Light Source and the Ray Table Base on the
Optics Bench. Put the Ray Table on the base. 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.
Position the Rhombus on the Ray Table as shown in the
diagram. The triangular end of the Rhombus is used as a
prism in this experiment. Keep the light ray near the point
of the rhombus for maximum transmission of the light.
Rotate the rhombus until the angle (
θ
) of the emerging ray
is as large as possible and the ray separates into colors.
(a) What colors are seen and in what order are they?
(b) Which color is refracted at the largest angle?
OS-8517
P
A
TTERN
LIGHT
SOURCE
COLOR
TO
REPLACE BULB SEE
INSTR
UCTION MANUAL.
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
Rhombus Ray Box
Figure 3
Color
Normal to Surface
Single Ray
θ