Richard Clark wrote:
"Again, what is the vector of direction for the light bulb?"
Electromagnetic waves include light and heat whicjh have extremely short
wavelengths. The light bulb may not be a perfect point source but the
waves travel away from the source with the velocity of light and consist
of electric and magnetic fields that are at right angles to each other
and also at right angles to the direction of travel. Wave energy is
divided 50-50 between the electric and magnetic fields.
Many frequencies (colors) make up the radiation from a light bulb. Much
more heat is radiated than visible light.
In a radio wave the essential properties are frequency, intensity,
direction of travel, and plane of polarization, For the constituents of
light bulb radiation, it is the same.
300 million m/sec is the velocity and this equals the product of
frequency X wavelength. Emissions of a light bulb are of extremely high
frequency but of extremely short wavelenggth too.
All points on a wavefront are equidistant from the source and emerged
simultaneouslly so they share the same phase.. From a point source light
bulb we would be in the far field.
The field is transverse. The power flow (J.D. Kraus` words), or Poynting
vector, is entirely radial.
Best regards, Richard Harrison, KB5WZI
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