# Magnetic fields & electromagnetic induction

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#1
Hi, im just wondering are there 2/theoretically infinite no. of magnetic fields, for say a current carrying wire, place in between 2 bar magnets?

For example, if a current carrying wire is place in a magnetic field, between 2 bar magnets, it will experience a magnet force (from flemings left hand rule).

However, am I right in saying there will be a magnetic field surrounding the current carrying wire anyway, due to it carrying a current? (So there will be a "double" magnetic field effectively?).

Also, same with generators. If there is relative motion a wire (not carrying current) in a magnetic field, between 2 bar magnets, then a current will be induced across it?
But then since it is now carrying a current, it will also prodce a magnetic field of its own? (So you almost get an endless loop of magnetic fields?)

Is my understanding here correct? And how do these 2 magnetic fields "interact"?

Thanks

Note: im doing aqa spec, physics a
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5 years ago
#2
(Original post by JohnnyDavidson)
Hi, im just wondering are there 2/theoretically infinite no. of magnetic fields, for say a current carrying wire, place in between 2 bar magnets?

For example, if a current carrying wire is place in a magnetic field, between 2 bar magnets, it will experience a magnet force (from flemings left hand rule).

However, am I right in saying there will be a magnetic field surrounding the current carrying wire anyway, due to it carrying a current? (So there will be a "double" magnetic field effectively?).

Also, same with generators. If there is relative motion a wire (not carrying current) in a magnetic field, between 2 bar magnets, then a current will be induced across it?
But then since it is now carrying a current, it will also prodce a magnetic field of its own? (So you almost get an endless loop of magnetic fields?)

Is my understanding here correct? And how do these 2 magnetic fields "interact"?

Thanks

Note: im doing aqa spec, physics a
Look up 'back emf' and Lenz's law.

It's essentially conservation of energy/momentum.

The e.m.f. set up in the conductor by moving the through a magnetic field, will generate a magnetic field (induced field) which will oppose any change in the motion/field.

The same is true for a changing current - an e.m.f. will be set up in the conductor in opposition to the changing current.
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