When a current flows through a
conductor, it produces
a magnetic
field. The shape of the magnetic
field
depends on the shape
of
the conductor.
You need to know the shape of the
magnetic field
for a straight wire (shown below) and a coil.
What is the Shape
of a Magnetic Field
around a Straight Wire?
Iron filings on a
piece of paper will line up with the
magnetic field. The magnetic
field around a
straight
wire is circular, at right angles to the wire.
You can work out the direction of the field using your
right
clenched fist. Point your thumb upwards in the
same
direction as the current. The direction of the field
is the same
direction in which your fingers
curl.
Reversing the direction of the current
will reverse the magnetic field direction.
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