3B Scientific SEK Optics - Manual (Page 58)

2
nd
experiment
1. Attach the second mask onto the screen!
2. Repeat the experiment with the three-slot aperture! Insert a red colour filter into the aperture holder
and the holder between the optical lamp and the screen!
3. Mark the focal point and determine the focal length of the red light! Enter the value in table 2!
4. Repeat the experiment with a blue colour filter and mark the focal point!
5. Determine the focal length for the blue light and enter the value in table 2!
6. Compare the focal lengths for the red and the blue light!
Analysis
Table 1 Focal lengths for different parallel beams of light
Light
Focal length f
in cm
white light, short focused parallel beams
white light, long focused parallel light
Table 2 Focal lengths for light of different colours
Colour of light
Focal length f
in cm
red light, short focused parallel beams
blue light, short focused parallel beams
ELWE Physical experiments for education in natural science and engineering
Repr
odu
c
ti
o
n
is
a
llo
w
ed
onl
y
fo
r
u
s
e
w
it
h
E
L
W
E
-e
qui
p
m
en
t.
2 SEG - OP 4.9 Image Defects