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Model No. OS-8515B Teacher’s Guide
53
Experiment 13: Telescope
Typical results:
Answers to questions: 1. The image is inverted. 2. It is a virtual image.
Further study, Image Formed by the Objective Lens: The objective lens forms a real, upright image;
to see it, hold a sheet of paper at distance d
i1
from the objective. When a pencil is placed at this location, it’s vir-
tual image, viewed through the eyepiece lens, coincides with the virtual image of the grid pattern viewed through
both lenses.
Further study, Object at Infinity: When adjusted for a distant object, the distance between the lenses is
equal to the sum of the focal lengths.
Experiment 14: Microscope
Typical results:
Answers to questions: 1. The image is inverted. 2. It is a virtual image.
Further study, Image Formed by the Objective Lens: The objective lens forms a real, upright image;
to see it, hold a sheet of paper at distance d
i1
from the objective. When a pencil is placed at this location, it’s vir-
Table 13.1: Results
Position of Objective Lens 63.4 cm
Position of Eyepiece Lens 102.2 cm
Position of Screen 0.0 cm
Observed magnification -5
d
o1
63.4 cm
d
i2
-102.2 cm
d
i1
29.2 cm
d
o2
9.6 cm
Calculated Magnification -4.9
Percent Difference 2%
Table 14.1: Results
Position of Objective Lens 20.9 cm
Position of Eyepiece Lens 54.9 cm
Position of Screen 0.0 cm
Observed magnification -3
d
o1
20.9 cm
d
i2
-54.9 cm
d
i1
19.2 cm
d
o2
14.8 cm
Calculated Magnification -3.41
Percent Difference 12%
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