Why magnetic field from a current carrying conductor obey inverse-square law?

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SUMMARY

The discussion centers on the behavior of magnetic fields generated by current-carrying conductors, specifically addressing the misconception that they follow an inverse-square law (1/r²). It is established that the magnetic field from an infinite linear conductor actually decreases with distance as 1/r, not 1/r². The conversation also touches on the differences between static magnetic fields and those produced by alternating current (AC), clarifying that static fields do not exhibit the same decay as radiation fields.

PREREQUISITES
  • Understanding of electromagnetic theory
  • Familiarity with the Biot-Savart Law
  • Knowledge of static and dynamic magnetic fields
  • Concept of electric fields from point charges
NEXT STEPS
  • Research the Biot-Savart Law for calculating magnetic fields
  • Study the differences between static and dynamic magnetic fields
  • Explore the implications of electromagnetic radiation from AC currents
  • Investigate the geometric interpretations of magnetic fields around conductors
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Students of physics, electrical engineers, and anyone interested in the principles of electromagnetism and the behavior of magnetic fields in various configurations.

NANDHU001
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I have read that the electric field from a point charge fall off as 1/(r*r) since it is analogous to
variation of intensity of radation from source (whose geometric proof depends on solid-angle), similarily is there any geometric explanation why magnetic field in the stated case fall off as 1/(r*r).
 
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Bizarre "proof" that the static electric field is analoguous to a radiation... What about the gluon force? It increases over distance. What tells the previous reason in this case?

As for the static magnetic field... It cannot decrease as 1/R^2 because this would need a permanent current in an open wire. Either it's static, and then you need to close the circuit, and this loop creates a field as 1/R^3, or you have an antenna which accepts only AC current, and radiates an electromagnetic field, not a static magnetic one.

So 1/R^2 exists only as a computation intermediate of static magnetic fields.
 
NANDHU001 said:
similarily is there any geometric explanation why magnetic field in the stated case fall off as 1/(r*r).

It doesn't, does it?
The magnetic field of an infinite, linear conductor goes like 1/r where r is the distance from the wire (along the radius of a cylinder coaxial with the wire).
Maybe you mean a different geometry of the current carrying conductor?
 

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