E&M
> Magnetic Fields and Forces > Force on Current-Carrying Wires
DCS#
5H40.10
FORCE BETWEEN
PARALLEL
WIRES
APPARATUS
parallel wires hanging from
ceiling over
lecture bench
201
30 A DC power supply or 12 V
marine battery
202-08-F
dpdt switch
214-01-E
DESCRIPTION
Turn on the power supply and flip
the switch
to show
attraction between wires carrying parallel currents and repulsion
between antiparallel currents.
Note that the forces are not the same size in the two cases - the
current through the parallel wires is smaller because of the additional
resistance of the third wire leading to the overhead grid.
NOTES
Set the power supply to about 6 V so
that 20 A
flows through wires. The wires are intended to carry only 10 A,
so
switch
should not be closed for more than a few seconds.
