transward (imported) wrote: Sun Nov 17, 2013 3:55 am
A minor point. If my memory serves me, that is referring to a point source of radiation. On power lines where there is a line source of radiation the power is proportional to the inverse of the distance (1/r) rather than the inverse of the squared distance. At least until the distance from the power line is great in relation to the length of the line.
Transward
Yes, that is for the point source.
I've done a bit of calculation,
basically said, that a line source is a collection of point sources. Then, by the principle of superposition, I summed all fields of those points:
for one point: p/(r²+x²), where x is a distance from the point, p is source intensity, and r is radius.
Then I integrated this by x from -∞ to ∞, to calculate sum of field strengths for infinitely long wire. Ok, I cheated and used maxima, a symbolic mathematics software, and got:
πp/r
So, yes, you remember right.