P3 - Magnetic Fields Flashcards
What is a magnetic field?
A region where magnetic materials and wires carrying currents experience a force acting on them.
How can magnetic fields be represented?
By field diagrams.
Which way do the arrows on the field lines of a field diagram go?
From the North Pole to the South Pole.
What rule is used for magnetic fields?
The right hand thumb rule.
What is the right hand thumb rule?
Make a thumbs up sign.
Your thumb is the current direction, your curved first finger is the magnetic field direction.
What is the magnetic field inside a coil of wire like? [2].
Strong and uniform.
What is the magnetic field outside a coil of wire like?
Like a bar magnet.
What’s another word for a coil of wire?
A solenoid.
How can you increase the strength of the magnetic field around a solenoid?
Add a magnetically ‘soft’ iron core through the middle to make an electromagnet.
What does a magnetically soft material do?
Magnetises and demagnetises easily.
What are magnetically soft materials used for?
Something that needs to switch it’s magnetism on and off.
Why are electromagnets useful?
They must be constantly supplied with current so they can be switched off when you want.
Name two materials that magnets can attract and pick up?
Iron and steel.
Where are electromagnetic used?
In cranes in scrap yards and steel works.
Why can’t ordinary magnets be used in cranes?
The crane wouldn’t be able to let go of the object.
