

Probability Amps
Name: Unknown
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993
Question:
How do physicists determine the direction of probability amplitude
for all types of light? I know that red light has a rotation of about 36,000
times per inch traveled. Does this have any relation to the frequency of this
light?
Replies:
Yes, your number 36,630 is the number of wavelengths of red light
in an inch. The wavelength times the frequency is equal to the speed of
light, so there is an indirect relationship to the frequency. For my number I
assumed that the wavelength of red light is 7000 angstroms. The frequency
would be 4.2 times 10 to the 14th power. Probability amplitudes are something
different.
Sam Bowen
The relation between the wavelength of light and its frequency is
given by: wavelength * frequency = speed of light (=300,000 km/second). So,
for visible light, which covers wavelengths from 400 to 700 nanometers (4 to 7
X 10^7 meters, or 1.5 to 2.7 X 10^5 inches) the frequencies go from 7.5 to
4.2 x 10^14 Hertz (1 Hertz = 1 cycle per second). More on the human scale are
radio stations  for example, an FM station at 100 Megahertz (a frequency
which can be generated by ordinary electronics has a wavelength of: 3 x 10^8
meters/second/1 x 10^8 Hz = 3 meters. The ideal antenna for picking up radio
signals is about one half of a wavelength, or about 1.5 meters (= 5 feet) for
this frequency which, if you think about it (think of a car antenna), is about
the size people actually use! For our radio station, the radio waves, like
light, are known as "electromagnetic" waves, and have electric and magnetic
fields associated with them (That is why you can generate them with an
electrical circuit). An electric field is something that causes an electrical
charge to move in the direction the field is pointing, and similarly a
magnetic field causes a magnet to orient itself along the direction it is
pointing. So, at any instant, the radio waves have a certain collection of
these electric and magnetic fields spread out all over the place. Imagine
freezing this collection of fields, and testing the directions while moving
towards and away from the station transmitter. What you will find is that
first of all the fields are always pointing perpendicular to the lineofsight
from the transmitter (they never point along the direction they are going) and
that the electric field is always perpendicular to the magnetic field. You
will also find that every 1.5 meters (1/2 of a wavelength) both the electric
and magnetic fields flip direction, so that after a full 3 meters, they are
back where they started again. That is why they are called waves! Now
unfreeze it. 1 of over the frequency is 10^8 seconds, which is called the
period. You will find that every 1/2 period (5 x 10^9 seconds) in time, the
electric and magnetic fields everywhere flip directions, so that after a full
10^8 seconds, they are again back where the started. So the frequency (100
million inverse seconds) is the number of times a second the fields do one
full cycle. The same (much faster and smaller) is true of light.
Arthur Smith
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Update: June 2012

