magnetism Flashcards Preview

Physics > magnetism > Flashcards

Flashcards in magnetism Deck (19):
1

ferrite

a magnetic material used on fridge magnets or to keep cupboards shut

2

neodynium

'rare-earth' magnets in the headphones used in MP3 players

3

ferrous materials

are magnetic materials that contain iron

4

electromagnet

a coil of wire with an iron core

5

hard magnetic material description

retains magnetism well, but difficult to magnetise in the first place

6

soft magnetic material description

easy to magnetise but easily loses magnetism

7

examples of hard magnetic material

hard steel

8

examples of soft magnetic material

soft iron

9

uses of hard magnetic material

compass needles, loudspeaker magnets

10

uses of soft magnetic material

transformers, radio aerials

11

two methods to magnetise

stroke material with permanent magnet in one direction

place material in strong magnetic field produced by an electromagnet

12

three methods to demagnetise

place magnet in the field of an electromagnet that is connected to an alternating current supply

heat the magnet

hammer the magnet. when a magnet is placed in a east-west direction and hammered it loses magnetism

13

permanent magnets

their magnetism is there all the time and cannot be turned off like electromagnets

14

induced magnetism

these metals will be attracted to a magnet if placed within a magnetic field. in this situation they act as a magnet but only whilst being in the magnetic field.

15

magnetically hard

substances that can be permanently magnetised.

16

magnetically soft

can only be temporarily magnetised

17

what metals can magnets be made from

iron, nickel, cobalt

18

difference between iron and steel

iron loses any induced magnetism quickly whilst steel can be permanently magnetised.

19

difference between permanent magnet and electromagnet

permanent made from 'hard' magnetic material. electromagnet is made by a current running through a coil of insulated wire so is 'soft' magnetic material

permanent provides constant magnetic strength which electromagnets don't

electromagnets control magnetic flux whilst permanent cannot.