S + P- Magnetism

If two magnets are placed close to each other

• Like poles will repel, unlike poles will force themselves apart 

• Like poles will attract, unlike poles will repel

• Like poles will repel, unlike poles will attract

• Like poles will force apart, unlike poles will repel

The flow of flux in a simple bar magnet is said to

• Start at the centre of the magnet and flow towards each end

• Flow from the north seeking end and enter at the south seeking end

• Flow from the south seeking end and enter at the north seeking end

• Only flow when the magnet has been polarised with a current

The unit and symbol for magnetic flux is

• Tesla B

• Theta Ɵ

• Sigma  Σ

• Weber ɸ

The unit and symbol for magnetic flux density is

• Tesla B

• Theta Ɵ

• Sigma   Σ

• Weber ɸ

Lines of magnetic flux are said to

• Never cross one another

• Form open loops

• Take the easiest path

• Only exist in the magnet

The formula for determining magnetic flux density is

What is a magnet?

• Any material capable of attracting metal objects

• A material that once heat treated will become magnetic

• A particular material found by mining near the earth’s magnetic core

• Any material that can attract ferrous metals

What happens when a magnet is cut in half?

• All magnetism is lost in both pieces

• Each new piece will have a north and south pole

• One half will have the stronger lines of flux

• Only one piece will be magnetic the other non-magnetic

Where in a bar magnet is the magnetic field strongest?

• In the centre of the magnet

• Towards the North Pole

• Towards the South Pole

• At the ends of the magnet

How are ‘eddy currents’ created?

• By installing line or neutral conductors in a metal enclosure

• By installing line and neutral conductors in a metal enclosure

• By installing line and earth conductors in a metal enclosure

• By not earthing the installation at suitable points