How Does Energy Disperse from a Finite Line Source?

[jlenard]

Inverse square law

Does anyone have an absolute basic understanding of
"first order principles of energy dispersion"

(A) Energy from a point source disperses spherically
at the inverse square law.
(B) Energy from an infinite line source disperses cylindrically
at ½ inverse square law.

Question?
What is the energy dispersion from a finite line source?

Measured 90deg from center of line source, at distance x, where transition from ½ inverse square law, back to, inverse square law, takes place.

Can anyone throw light on this question without diversions?
1 First order principles only.
2 In space, zero boundaries.
3 Line length magnitudes greater than any wavelength of energy dispersed.

Thank you.

 

[Valerie Park]

Answer: Energy from a finite line source disperses cylindrically at the inverse square law until it reaches the point where the distance from the source is equal to the length of the line source. At this point, the energy dispersion transitions from an inverse square law to a ½ inverse square law.