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Biot&Savart vs Ampere



Perhaps some documentary examples of these two
experimental relations will help you decide?

Brian W

"Every linear conductor carrying a current is equivalent to a simple
magnetic shell, the bounding edge of which coincides with the
conductor, and the moment of which per unit of area, that is, the
strength of the shell, is proportional to the strength of the current."
Ampere, Theorie des phenomenes electro-dynamiques,
Memoires de l"Institut, IV 1823

dH = int(A i. dL/r^2 sin theta)
for dL is an element of the circuit in which current i flows,
r is the distance from that element to point at which the intensity
is found, theta the angle between the current carrier and the radius.
Integral is taken round the circuit. A arbitrary constant
dH the magnetic intensity.
(Ampere: defined in Physics, Starling & Woodall)

Integral B. dL = mu zero. I enclosed
(Ampere: defined in U Physics, Crummett & Western)


"The magnetic field due to current flowing in a long straight
conductor is directly proportional to the current and inversely
proportional to the distance of the point of of observation
from the conductor"
Biot & Savart - per Penguin Dictionary of Physics: V H Pitt

dB = mu zero/4pi * I dL sin theta / r^2
(Biot_Savart: defined in College Physics: Webber,White,Manning)


At 12:49 PM 4/12/02, Paul Giusti wrote:
hi all. is B=mu noughttimes current/2pi r not biot-savarts law. one of my
parents friends, a physics teacher, says it is ampere's law. who is correct?

Brian Whatcott
Altus OK Eureka!