Magnetic field

The field created by an electromagnetic coil

In the visual on the left, you can see a circuit with a coil or solenoid near a compass. When you close the circuit the coil behaves like an electromagnet and it attracts the magnet in the compass towards one of its poles.

How can we tell which of the poles is north and which is south in the electromagnet that has just been created?

How can you make the magnetic

field more intense? You will be able to answer all these questions after you have studied the following visual: .

Through some "experiments", you have studied the elecromagnetic field created by straight cables and coils. In both cases we could have used Ampère's law, which is also applicable to many other cases. You can study Ampère's law in , and try to deduce the value of B theoretically.

	Natural magnets
	Lines of force
	Magnets and currents
	Conclusions

	on a charged particle
	on a straight cable
	on a loop
	Conclusions

	by a charged particle
	by a rectilinear current
	by a coil
	An explanation of natural magnetism
	Conclusions

	Magnetic flux
	The laws of Faraday and Lenz
	Self-induction
	Conclusions

	The generation of alternating currents
	A circuit of alternating current
	Conclusions