MAGNETIC FLUX DENSITY
- The Magnetic Flux
Density of a magnetic field is defined as the force F acting
per unit current I in wire of unit length l at right angles to the
ü F=BIl (Your new
- The direction of the
Current, Field and Movement correspond to the seCond finger, First
finger and thuMb of one's left hand: Fleming's Left Hand Rule.
- Magnetic flux density,
instead of being "Newtons per Amp-metre", has its own units, the
- When the movement is
not perpendicular to the field, one must resolve the perpendicular
component of the field.
- If the angle, q, is the angle between
the direction of the field and that of the horizontal component of the
field, then the magnitudes of the horizontal and vertical components are B
cos q and B sin q, consecutively. The
equation therefore normally becomes
ü F=B Il cos q
- For a rectangular coil
with a central point of pivot in a magnetic field, the force experienced
would also be affected by the number of turns n, and distance
between the two sides of the coil that run perpendicular to the field d.
This makes our equation (the one you'll have to learn to love!) F =
B Il d n cos q, which, quite frankly,
looks horrible. If you're sharp, you will have noticed that d * n is equal
to A the area of the coil, so remember:
F = B I A n cos q (Your new very good
friend "Bianka" if you imagine the q as an "a"!
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Copyright © Simon van Leishout 2000