Experiment 15: telescope, Experiment 16: microscope – PASCO OS-8515C Basic Optics System User Manual
Page 67
®
M o d e l N o . O S - 8 5 1 5 C
T e a c h e r ’ s G u i d e
67
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.
Further study, Galilean Telescope:
The distance between the lenses should be about 10 cm (the differ-
ence in magnitude of the focal lengths). The image is upright and the magnification is positive.
Typical results:
Answers to questions:
1. The image is inverted. 2. It is a virtual image.
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%
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%