Magnetism From Electricity:
1. Describe Oersted's experiment on currents and magnetic fields and state the principle he discovered.
2. Define electromagnetism.
3. Explain the structure and use of electromagnets.
4. Describe the structure and use of electric motors.
5. Distinguish between direct and alternating current.
As we stated earlier, the source of magnetism ultimately lies in the electrons of the magnetic material. Therefore, it makes perfect sense that the current flowing through wires also creates magnetic fields. Oersted discovered this while placing a compass near a wire with current. He noticed that the current in the wire caused the compass to orient itself 90 degrees from the moving current. When he switched the the compass also switched.
electric current flows over a compass it changes the direction of the needle by
current is reversed the needle changes by 180o.
an electric current flows through a wire it gives rise to a magnetic field.
direction of the field depends on the direction of the current
strength depends on the amount of current
discovery of the electrons magnetic field led to the production of
electromagnets. Remember that electromagnetism
is the relationship between electricity and magnetism.
are made by wrapping wire around a soft iron core.
Are very strong magnets
is increased by increasing the number of loops or the amount of current
magnetic properties are only present when there is current present
electric energy into mechanical energy.
an electromagnet that rotates on a shaft
direction of the current is continually switched causing the magnetic poles to
using AC or DC and a reversing switch called a commutator
alternating repulsion and attraction causes the electromagnet to spin on its
is an instrument used to detect very small currents.
of a coil and a magnet
used to detect the direction of the current