Lab & Pre-lab #11

Lenses and Images v 0.1
Step 2: Remove the screen. Now look toward the lens from a position about two feet beyond
where the screen had been located. Look for the image of the ”F” floating in front of the
lens. It will be inverted, just like the image that had been projected on the screen. It
should appear to be in the same position where the screen had been. Each member of
your group should make this observation.
lamp
former screen position
eye
Figure 8: Locating a real image with your eye, using parallax
Step 3: To locate the position of this image in space more accurately, have one member of the
group hold their finger above the position at which the screen had been located, as in the
figure above. Hold the finger high enough that it does not block the light coming through
the lens. Another member should then look at the image while moving their head left and
right a small amount.. As you do this, the image will appear to move relative to objects
in the background. But the image and the finger will appear to move together if they are
the same distance from your eye.. (This phenomenon is called parallax – it is how we tell
distances to objects with our eyes.)
Question 1.10 Was the image you observed in space at nearly the same location at which
the image had been formed on the screen
Question 1.11 Did the image you observed in space have the same characteristics as the
one projected on the screen, that is, was it about the same size Were both inverted
Activity 1.5: Observing a virtual image
In last weeks laboratory you discovered that when an object is too close to a lens, the
light rays coming out of the lens diverge, as if they were coming from some single point
PHYS-204: Physics II Laboratory 9