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In physics, the conventional units of magnetic field are H (magnetic flux strength) and B (magnetic induction). However they seems not to be abbreviated symbols. I'd like to know what is the terminological roots of these two symbols.

2007-04-16 23:12:07 · 6 answers · asked by spak 1 in Science & Mathematics Physics

6 answers

These are symbols for the total and free magnetic field itself, not the units. They may have just started running out of capital letters. In electromagnetism alone, C, D, E, F, I, J, L, M, P, Q, V, and Z are taken. The best candidate, M, is magnetization, for example.

Oh yes, and A and R are taken too. (vector potential and resistance)

2007-04-17 03:17:52 · answer #1 · answered by Dr. R 7 · 0 0

A magnetic field exists in three dimensions of space. We can describe a three dimensional volume as a certain area times a certain length.
Magnemotive force (mmf) = total force that produces
magnetic flux. B is expressed as the magnetic
induction, or flux density. If we know the total flux,
the density must be that value divided by the interior
area or A. Thus this first method gives the magnetic
interaction with those first two dimensions to
determine the density. The English unit of mmf is the
Ampere-turn, the equivalent cgs (centimeter/gram
second) unit is named the Gilbert, where the
conversion ratio is shown by 1 Gilbert=.796 Amp turns,
and conversely 1 amp turn= 1.25 Gilbert.
The field intensity or H is the force per unit length
of flux path. We are simply now applying the
definition of B for 3 dimensional space, where in the
English system this is made as amp-turns/inch. The cgs
equivalent is the Gilbert/cm, named the Oersted. 1
Oersted= 2.02 amp-turns/inch.

Around the early 80's I also attended Akron State Univ
after dropping out, but the different text from that
same Elementary Classical Physics course does not seem
to deal with H at all, as the other text did. In the
early 90's I purchased another Physics text,(Physics
for Scientists and Engineers) in which the following
is noted on pg 654;

We have named B the magnetic field and H the magnetic
intensity. These names are not universal. Sometimes B
is called the magnetic flux density and H is called
the magnetic field. Admittedly, the terminology is
confusing, and universal adoption of a single set of
terminology is unlikely in the near future.
Fortunately, the usage of the symbols B and H as we
have defined them is nearly universal. Thus the
calculation of a magnetic force on a moving charge or
a current nearly always involves B; similarly H is the
appropriate field in Ampere's Law.

It has cost me a bit of time to try and understand
that thing with Amperes law, as I did not pay
attention then, and integrals need that concept of
summation. I think it can be summed up by guessing
that a linear relationship is made between the amount
of magnetic field B obtained at a certain distance r
away from a conductor of i current. This becomes a
ratio, where a constant is derived. That constant is
known as the permeability of free space,mu(0) or k
determined by the equation (B)(2*pi*r)=k*i

What it seems to be is that B/H= the permeability
constant k, which of course also changes with core
material. To end this long post this is from pg 491
concerning ferromagnetics;
Iron,nickel,cobalt and gadolinium are the only
ferromagnetic materials at room temperature. Because
of the complicated relation between the flux density B
and the magnetic intensity H in a ferromagnetic
material, it is not possible to express B as an
analytical function of H.{Note; I assume the
analytical equation with k=1 then does always apply
with a non saturable air core inductor} Instead the
relation between these quantites is represented by a
graph of B vs H, called the magnetization curve of a
material. The permeability, equal to the B/H ratio {is
not constant for that material.}

2007-04-17 09:36:06 · answer #2 · answered by harvich 3 · 1 1

Units Of B Field

2016-10-14 10:54:17 · answer #3 · answered by ? 4 · 0 0

B is the magnetic flux passing through the in a unit ares of magnet H is the magnetic force of lines passinng from norht to south in any medium

2016-05-17 07:10:53 · answer #4 · answered by ? 3 · 0 0

H and B aren't the units, they're the symbols for magnetic flux strength and magnetic field. Same way F is the symbol for force but its units are newtons (N).

2007-04-17 00:40:41 · answer #5 · answered by murnip 6 · 0 0

Unit of B is TESLA.

2007-04-16 23:21:27 · answer #6 · answered by Anonymous · 0 0

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