 Faraday's
First Electric Motor
A copper wire is suspended from a point
along the axis of the magnetic field so that its
lower end dips into mercury. On passing current
through the wire, it rotates. This happens due to
the fact that whenever a current carrying conductor
lies in a magnetic field, magnetic forces are exerted
on the moving charges within the conductor. These
forces are transmitted to the material of the conductor,
and the conductor as a whole experiences a force
distributed along its length. |
 Jacob's
ladder
When a current is passed through the 'V' shaped
electrodes, a small spark starts at the bottom of
the electrodes and travels up and gets larger as
the space between the electrodes widens. The spark
pops off at the top and the cycle repeats. When
a high voltage is applied between the rods (by stepping
up an input of 220 V), it ionises the air in that
region and it carries the current between the rods.
As the hot air rises, the spark climbs. When the
gap is too wide for the voltage supplied, the spark
can be maintained and it snaps.
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Chaotic Pendulum
When a set of ceramic magnets is placed
right under a pendulum, it exhibits a chaotic motion
instead of its usual linear motion. This happens
because of the mutual repulsion among the magnets
and the attraction between the iron bob (pendulum),
giving rise to net-forces in different directions.
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Magnetic
Levitation
 A
magnetic field will be created around a current
carrying conductor and when a non-magnetic conductor
is placed in such a field, current is induced in
it. This is Eddy Current. Eddy current creates a
magnetic field of its own. A force of repulsion
(as predicted by Lenz's Law) results due to the
two magnetic fields. Hence, the non-magnetic conductor,
here the aluminium disc, rises or levitates. Iron
filings sprinkled on the plate reveals the direction
of the magnetic lines of force.
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AC
induction 
A primary coil of 2000 turns of enamelled copper
is wound on a PVC pipe that has iron rods stuffed
in it to act as core. Another secondary coil of
60 turns wound on a larger diameter PVC pipe is
placed on it. When a 6 V bulb connected to the secondary
coil is made to slide over the primary coil (supplied
with 220V AC current), the bulb glows with increasing
intensity as it is lowered into the core of the
first coil. This happens because of the induction
of electromotive force from one coil to the other.
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Thermoelectricity
Wires of two dissimilar materials joined at the
ends to create a junction. The free ends are connected
to the galvanometer and the junction is heated.
The needle in the galvanometer deflects indicating
the production of electric current. This is thermoelectricity,
a method of producing electric current by heating.
This happens because of the difference in the temperatures
at the two ends of the wires, causing an electric
current to flow. Here the experiment is demonstrated
with different pairs of metals.
Charan
C S
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6:35:01 PM 
