Chris R. Brown's physics and astronomy stuff
Optics Puzzler
|
|
|
|
|
|
|
|
Chris R. Brown's physics and astronomy stuff Optics Puzzler
|
|
||
|
|
|
|
||
|
|
|
|
|
|
|
|||||
|
|
||||
|
|||||
|
||||
|
|
Here's a puzzler demo for your students. Rig up a low power unmodulated laser several
meters from a photovoltaic cell connected to the input of an audio amplifier, as shown below.
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
Then take a glass plate - a microscope slide will do - and put it in the beam. Rotate the plate as suggested in the illustration. (clockwise is ok too) An audio whistle will be heard in the loudspeaker. The frequency of the whistle increases with the rotation rate of the glass plate. Doppler shifts are NOT the cause of this effect! |
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
|
|
|
|
|
|
||||
|
||||
|
||||
