Experiment 14: virtual images – PASCO OS-8515C Basic Optics System User Manual
Page 66
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B a s i c O p t i c s S y s t e m
T e a c h e r ’ s G u i d e
66
Part 1, notes on procedure:
(Step 4) The image is upright and appears smaller than the object.
(Step 5) Answers will vary. By observing parallax between the image and the light source, you can determine
that the image is in front of the object. (Step 8) When the negative lens is removed, the image on the screen goes
“out of focus.”
Part 1, typical results:
Part 1, answers to questions:
1. You know that the final position of the light source and the original posi-
tion of the virtual image are the same because both caused the +200 mm lens to form an image in the same place.
2. Answers will vary. 3. M
1
is positive, meaning that the image is upright.
4.
5.
Part 2, notes on procedure:
(Step 4) The image is upright and appears smaller than the object.
Part 2, typical results:
Part 2, Answers to questions:
1. The magnitude of d
i
is less than d
o
. With a plane mirror, d
i
and d
o
would
be of equal magnitudes. 2. M
1
is positive, meaning that the image is upright.
3.
d
o1
20.0 cm
d
i1
-8.3 cm
M
1
0.42
d
o
20 cm
d
i
-6.5 cm
M
0.33
Light
source
Real image
Screen
+200 mm
lens
Virtual
Image
-150 mm
lens
Real image
Screen
+200 mm
lens
Light
source
Half-
screen
Virtual image
Screen
Mirror