Analysis – PASCO OS-8515C Basic Optics System User Manual
Page 44
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B a s i c O p t i c s S y s t e m
E x p e r i m e n t 1 4 : V i r t u a l I m a g e s
44
4.
Look through the half-screen into the mirror. Describe the image of the
half-screen. Is it upright or inverted? Does it appear to be larger or smaller than
the object?
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5.
Guess where the image is. Place the viewing screen on the bench at this location
(see Figure 14.6).
In the following steps, you will adjust the position of the viewing screen so that it is in
the same place as the virtual image.
6.
Look over the top of the half-screen (Figure 14.7a) so that you can see the virtual
image of the half-screen and the line drawn on the viewing screen at the same
time (Figure 14.7b).
7.
Move your head left and right by a few centimeters. If the line on the viewing
screen and the image of the half-screen are not at the same distance from your
eye, they will appear to move relative to each other. This effect is known as par-
allax.
8.
Adjust the position of the screen and check for parallax again. Repeat this step
until there is no parallax between the line and the image. When you move your
head, they should appear to be “stuck” together.
Analysis
The viewing screen is now in the same location as the virtual image.
1.
Record the object distance d
o
in Table 14.2.
2.
Calculate the image distance d
i
(the distance between the mirror and the virtual
image). Remember that it is a negative. Record it in Table 14.2.
Half-
screen
Mirror
Convex side
Viewing
screen
Figure 14.6
Line
Image
of half-
screen
Viewing
screen
Mirror
Half-
screen
Mirror Viewing
screen
Look into mirror
Figure 14.7a