PASCO OS-8500 INTRODUCTORY OPTICS SYSTEM - Manual (Page 49)

012-02744K Introductory Optics System
®
43
Experiment 19: The Projector
EQUIPMENT NEEDED:
-Optics Bench -Light Source
-75 mm Focal Length Convex Lens -150 mm Focal Length Convex Lens
-Variable Aperture -Crossed Arrow Target
-Viewing Screen -Component Holders (3).
Figure 19.1 Equipment Setup
Introduction
When an object is located between the focal point (f) and twice the focal point (2f) of a converging lens,
a real, inverted, magnified image is formed as shown in the diagram of Figure 19.1. If a viewing screen
is placed at the location of the image, the image will be focused onto the screen. In this case the lens
functions as a projector.
Procedure
Set up a projector as shown in Figure 19.1. Try both the 75 and 150 mm converging lenses.
➀ What happens to the image if d
o
is less than f? Can the image still be focused onto the Viewing Screen?
Why or why not? _______________________________________________________
_____________________________________________________________________________.
➁ What happens to the image if d
o
is greater than 2f? Can the image now be focused onto the Viewing
Screen? Why or why not? ____________________________________________________
_____________________________________________________________________________.
➂ Are there practical limits to the degree of magnification of the image? If so, what are they?
_____________________________________________________________________________.
Is it possible, using a single lens, to project an image that is uninverted? ___________________
_____________________________________________________________________________.
➃ Can the image formed by a projector be viewed without using a viewing screen? If so, where must the
observer be? _______________________________________________________________
_____________________________________________________________________________.
Viewing Screen
Variable Aperture
Crossed Arrow Target
d
o
d
i
f f
2f
75 mm Lens