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Question

Has the speed of propagation of a magnetic force field been measured? If so what is it?
Asked by: Colin Coulton

Answer

The term magnetic force field implies the application of a force on a distant object, say a piece of iron, by a magnetic field.

In order to generate a magnetic field that can be said to propagate, it is necessary to produce a changing field by turning on an electromagnet or removing a magnet from a magnetic shield such as a superconducting box. Changing magnetic fields are also produced around all radio transmitter antennas due to the changing current flowing in them.

When a magnetic field is changing, it is always accompanied by a transverse electric field, i.e., it is an electromagnetic wave. The relationships between changing magnetic and electric fields are summarized in the well-known Maxwell's equations.

Click here for a more detailed mathematical derivation and description.

The speed of electromagnetic waves is certainly known and is defined to be exactly 299,792,458 m/s in vacuum (same as the speed of light).
Answered by: Scott Wilber, President, ComScire - Quantum World Corporation


Science Quote

'There is no inductive method which could lead to the fundamental concepts of physics. Failure to understand this fact constituted the basic philosophical error of so many investigators of the nineteenth century.'

Albert Einstein
(1879-1955)


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