Page 7 - 10-phy-15 Electromagnetism

15. Electromagnetism eLearn.Punjab

The direction of the field produced by Fig 15.5 Right hand grip rule for a coil
a coil due to the flow of conventional
current can be found with the help of
right hand grip rule (Fig.15.5) stated as

If we grip the coil with our
right hand by curling our
fingers in the direction of the
conventional current, our
thumb will indicate the north

pole of the coil.

15.2 FORCE ON A CURRENT-CARRYING
CONDUCTOR PLACED IN A MAGNETIC FIELD

We know that electric current produces a magnetic field similar to that of a permanent magnet.
Since a magnetic field exerts force on a permanent magnet, it implies that current-carrying wire
should also experience a force when placed in a magnetic field.
The force on a wire in a magnetic field can be demonstrated using the arrangement shown in
Fig.15.6. A battery produces current in a wire placed inside the magnetic field of a permanent
magnet. Current-carrying wire produces its own magnetic field which interacts with the field of the
magnet As a result, a force is exerted on the wire. Depending on the direction of the current, the
force on the wire either pushes or pulls it towards right (Fig.15.6-a) or towards left (Fig.15.6-b).

Fig 15.6 Force on a current carrying wire in magnetic field V: 1.1

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