What Are They? –
A permanent magnet is made from a substance that is magnetized and
that has its own permanent and persistent magnetic field. An
electromagnet, on the other hand, is temporary.
How to Make an Electromagnet –
Many appliances that we use every day contain
electromagnets, usually hidden inside the device.
An electronic door lock contains an
electromagnet that opens the lock mechanism.
A solenoid is a coil of wire that is used to create an electromagnet. The
diameter of a solenoid is much smaller than its length. When a solenoid is
wound around a central iron core (piston) and attached to a source of
electricity, the solenoid generates a magnetic field, so that it acts like a
permanent (bar) magnet.
Uses of Electromagnets –
An electromagnet is useful because the magnetic field can be controlled.
It can be made stronger or weaker by increasing or decreasing the
QUESTIONS: Uses of Electromagnets –
Name three things mentioned in the article in which you will find the
type of electromagnet which applies force and moves something.
History of Electromagnets –
Danish scientist Hans Christian Orsted was the first to
discover the relationship between electric current and magnetism. While
giving a lecture in April of 1820, he notices that the needle of a compass
moving away from magnetic north as an electric current from a battery
was switched on an off.
Joseph Henry's Eletromagnet –
Henry's electromagnet was the strongest that had ever been built. It also
demonstrated that the electromagnet is best built differently depending
on how many batteries will be attached to it.
Ohmic Losses and Inductive Voltage Spikes –
Ideally, all the energy in an electrical circuit would remain in the circuit,
but in reality, some energy in an electrical circuit is lost as heat. In physics,
resistance is measured in units called ohms.
Cyclotron Explained –
A cyclotron is a device used to accelerate charged particles to high
energy levels. The principle behind it is that a charged particle moving
normally near a magnetic field is acted on by a
magnetic Lorentz force which causes it to move
in a circular path.
Magnetic Levitation Trains –
A maglev train uses the force of
electromagnetism to both levitate
a train above its tracks and to
propel it forward. Here’s how it
Magnets and Motors –
Electric motors create magnetic fields with electric current flowing
through a coil. This magnetic field then causes a magnetic force that
generates physical movement (spinning).