User's Manual

Beginning Optics System Teacher’s Guide

Experiment 11: 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

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 12: 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

from the objective. When a pencil is placed at this location, it’s vir-

Table 11.1: Results

Position of Objective Lens 63.4 cm

Position of Eyepiece Lens 102.2 cm

Position of Screen 0.0 cm

Observed magnification -5

63.4 cm

-102.2 cm

29.2 cm

9.6 cm

Calculated Magnification -4.9

Percent Difference 2%

Table 12.1: Results

Position of Objective Lens 20.9 cm

Position of Eyepiece Lens 54.9 cm

Position of Screen 0.0 cm

Observed magnification -3

20.9 cm

-54.9 cm

19.2 cm

14.8 cm

Calculated Magnification -3.41

Percent Difference 12%