Lux et Veritas
Radiation, which is the motion of the electromagnetic field,
of which visible light is a small region, is due to the motion
of charges  Move a charge = radiate
C= λ f =
3x10^8 m/s
CMB@3K, not owl poop, everywhere in
space, this is exaggerated by a large
factor (of like 10,000K) = almost the big
bang…more later in the term
Energy/momentum
• E=hf
h = planck’s constant
= 6.63 X 10^(-34) (J*s)
• P = momentum = E/c c= speed of light
• E/B=c where E,B are field magnitudes
C (first method)
a microwave oven,a bag of marshmallows, and a ruler.
(The oven must be of the type that has no mechanical motion-no turntable or rotating
mirror. If there is a turn-table, remove it first.)
•cover dish with a layer one marshmallow thick.
•cook on low heat.
•Heat the marshmallows until they begin to melt in four or five different
spots.
•measure the distance between the melted spots. You will find that
one distance repeats over and over. This distance will correspond to
half the wavelength of the microwave, about 6 cm.
•Now turn the oven around and look for a small sign that gives you the
frequency of the microwave. Most commercial microwaves operate at
2450 MHz.
Velocity = Frequency X Wavelength
C (second method)