Magnets And Electromagnets Flashcards
(22 cards)
What is the magnet used in a magnetic compass?
A needle
What causes the rotational forces?
The rotational forces withing the earths liquid.
Why dies a compass have lightweight magnet wnd a fraction less bearing?
To make it easier to turn.
Whats one way to change a needle into a magnet.
Stroke against a magnet
How does an electromagnet work?
It works with the electrical current flowing through the coiled wires to make a magnetic field.
What advantage does an electromagnet have over a permanent magnete?
That it isn’t permanent and it can be switched on and off.
How dies an electric bell work?
Te switch is pressed which completes the circuit. A current flows through the coiled wires. This activates the electromagnet. The electromagnet attracts the iron armature which then hits the gong. The contacts are parted, disconnecting the circuit. The electromagnet is therefore de-activated. The metal springs back and reconnects the circuit, so the electromagnet is re-activated again. The cycle repeats itself.
Name 3 materials that can be sorted out by magnets?
Iron fillings
Paperclips
A compass
Question on paper abt magnets and electromagnets on fijle.
Because the forces were equal at that point in the graph.
How can we make an electromagnet stronger?
Increasing the current
Changing the material used as the core
Increasing the number of coils
What will happen when two north poles of two magnets are joined?
They will repel
How can you test for a permanent magnet?
By putting a normal permanent magnet’s north pole side to one end of the other metals side it should either attract or repel. Also you have to put the north pole of the permanent magnet to the other end of the magnet if it repels that means that it is a magnet.
Can magnetism be stopped? If so, what is the experiment for this question.
Yes. The experiment would be by putting different materials between the magnet and the paperclip to see whether the paperclip will fall or not. If it does fall then that means that material has stopped magnetism. If it doesn’t then it has no effect
What are the properties of a magnet?
Those that are magnetized and stay magnetized are called permanent magnet.
And those that don’t stay magnetized are called temporary magnets.
What is the domain theory of magnetism?
It explains where there is a limit to how strongly a particular material can be magnetized. If none of the domains of the magnetic material are lined up then it is an unmagnetized magnet if they are lined up then its known as a magnetized material.
What is the magnetic field?
It is the area around the magnet that experiences foce.
How can you see a magnetic field?
By using iron fillings and sprinkling them.
Which four materials are magnetic?
Steel, cobalt, nickel and iron
How can you destroy a magnet?
By banging it with a hammer or dropping it, heating it.
Two uses for electromagnets
A bell, motor
What is a compass and what does it do?
It is a device that helps you find directions north, south, east and west.
What is an electromagnet?
An electromagnet is something that is not a permanent magnet and can be switched on and off in current rather than it just being a normal magnet which can only tay magnetized, and never demagnetized .
