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

In summary, the electric field from a point charge falls off as 1/(r*r) due to its similarity to the variation of intensity of radiation from a source. However, there is no geometric explanation for why the magnetic field in this case also falls off as 1/(r*r). The static magnetic field cannot decrease as 1/R^2 and exists only as an intermediate computation. The magnetic field of an infinite, linear conductor follows a 1/r pattern, possibly in a different geometry of the current carrying conductor.
  • #1
NANDHU001
22
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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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  • #2
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.
 
  • #3
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?
 

1. How does a current carrying conductor create a magnetic field?

When an electric current flows through a conductor, it creates a circular magnetic field around the conductor. This is due to the movement of the electrons in the current, which creates a magnetic field perpendicular to the direction of the current.

2. Why does the magnetic field from a current carrying conductor obey inverse-square law?

This is because the strength of a magnetic field is proportional to the distance from the source squared. As the distance from the current carrying conductor increases, the magnetic field strength decreases in proportion to the square of the distance.

3. How is the strength of the magnetic field from a current carrying conductor calculated?

The strength of the magnetic field can be calculated using the formula B = (μ0 * I) / (2π * r), where B is the magnetic field strength, μ0 is the permeability of free space, I is the current, and r is the distance from the current carrying conductor.

4. Can the magnetic field from a current carrying conductor be shielded?

Yes, the magnetic field from a current carrying conductor can be shielded using materials with high magnetic permeability, such as iron or steel. These materials redirect the magnetic field lines, effectively shielding the area behind them from the magnetic field.

5. How does the magnetic field from a current carrying conductor affect nearby objects?

The magnetic field from a current carrying conductor can induce an electric current in nearby conductors, which can have various effects depending on the strength of the current and the material of the objects. It can also attract or repel other magnets, depending on their orientation and polarity.

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