Experiment Setup - 3B SCIENTIFIC PHYSICS U10371 Mode D'emploi

should be held parallel to the cross bar. If neces-
sary the copper strands can be carefully pulled
between two fingers until they are smoothed out.
In the region of the soldering points the copper
strands should not be bent (danger of breakage).
• The glass and aluminum rod are each suspended
on a thin thread, which might get somewhat
twisted. Before starting an experiment the rods
should hung individually on the stand until they
are no longer twisted.
• Maintenance: the electromagnetic experiment
apparatus is basically maintenance-free. To clean
simply wipe over it with soap and water. Solvents
like aceton, petroleum ether or ethanol (white
spirit or alcohol) can be used except in the area of
the label.
• If the cord of the glass or aluminium rod have be-
come knotted or shredded, thin sewing silk can be
used as a substitute. The sewing silk thread is first
wrapped around the respective rod approx. 3 times
and then tied in a knot. Then the rod is suspended
and balanced out horizontally by moving the sew-
ing silk thread along the rod. Finally the sewing
silk thread is permanently attached to the rod us-
ing fast-acting adhesive (observe the safety instruc-
tions of the glue manufacturer).
4. Experiment procedure and evaluation
4.1 Current-carrying conductor in a magnetic field

4.1.1 Experiment setup

• The two possible experiment set-ups can be seen
in Fig. 2.
1
2
3
5
Fig. 2: Experiment setup "current carrying conductor in a magnetic field".
1 2
Knurled screw, Cross bar,
1) If necessary, measure the horizontal distance between the copper wire and the knurled screw (5) with a non-magnetic ruler
4
3 4
Conductor swing, Pole piece,
• The experiment setup as specified in Fig. 2 (right)
is used to verify that the Lorentz force acts neither
in the direction of the magnetic field nor in the
direction of current flow. In the first case the con-
ductor swing would swing to the right or to the
left, in the second case it would be forced to swing
into or out of the plane of the drawing.
• Using the experiment setup specified in Fig. 2 (left)
the Lorentz force can be demonstrated qualitatively
and quantitatively. For the qualitative verification
the conductor swing is suspended vertically above
the poles of the magnet. When the current is
switched on, we then observe deflection which
gains in magnitude the more the current increases.
• For the quantitative determination of the Lorentz
force the 3 threaded bore holes are used which
are shifted at distances of 15, 30 and 45 to the left
of the perpendicular holes. If, for example – as
shown in the figure, the conductor swing is
mounted shifted to the left by 45 mm and the cur-
rent flowing through the conductor swing is set so
that the copper wire is right in the middle of the
magnetic field, then the swing's deflection from
the vertical also amounts to precisely 45 mm and
the Lorentz force corresponds to the returning force,
which the conductor swing experiences due to the
earth's gravity (see also experiment evaluation).
4.1.2 Experiment procedure
•
During the measurements it is expedient to note
down the following variables:
– the experiment number,
– the pole piece separation a,
– the pole piece width in the conductor direction b,
– the deflection c and
– the current Ι , which flows when the copper
wire is positioned in the middle
5
Flat headed knurled screw
6
1)
.
2
1
3