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Re: Magnetic N and S poles



I suspect that no introductory textbook published before 1945
defined B in terms of Lorentz formula. But I may be wrong.
Ludwik Kowalski

From "Analytical Experimental Physics", Lemon & Ference, 1943 :
"We may thus state that a magnetic fluix density exists at a point
whenever a force acts on a moving charged particle [but not on a
stationary particle] . . .
If a charge of q coulombs is moving with a velocity of v m/sec at right
angles to a flux density of B webers/m^2, then the moving charge
experiences a force of f newtons at right angles to both B and v which is
experimentally given by f = Bvq. [This equation] is a defining equation
for the flux density B."

They go on to the general case f = qvBsin(theta). The fictitious poles of
magnets are introduced much later but they are not used to define B or H;
nor is the inverse square law for poles ever uttered.
This is an introductory "General Physics" text.

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor