2,903
edits
Changes
no edit summary
: A [[Bar Magnet|bar magnet]] is a '''permanent magnet'''.
: '''Permanent magnets''' are used in a electrical [[D.C. Motor|motor]]s.
: A [[magnet]] is made of several small [[Magnetic Domain|magnetic domains]] which are regions in the [[magnet]] which act as smaller [[magnet]]s. In a '''permanent magnet''' these [[Magnetic Domain|magnetic domains]] are fixed in place and need [[energy]] to change their [[magnet]]ic direction.
: A '''permanent magnet''' can only lose its [[Magnetic Field|magnetic field]] under certain conditions:
*When it is struck with a sudden [[force]].
*When it is [[heated]].
*When an extremely strong external [[Magnetic Field|magnetic field]] is applied.
{| class="wikitable"
|-
|[[File:MagneticDomainsAligned.png|center|300px]]
|[[File:MagneticDomainsUnaligned.png|center|300px]]
|-
| style="height:20px; width:200px; text-align:center;" |When [[Magnetic Domain|magnetic domains]] are aligned the [[object]] has its own [[Magnetic Field|magnetic field]] so it acts like a [[magnet]].
| style="height:20px; width:200px; text-align:center;" |When the [[Magnetic Domain|magnetic domains]] are not aligned it does not have a [[Magnetic Field|magnetic field]] because the effect of the [[Magnetic Domain|magnetic domains]] cancels out.
|}
===References===
====AQA====
:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Permanent magnet, pages 242, 245, GCSE Physics; Student Book, Collins, AQA '']
:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Permanent magnets, page 223, GCSE Physics, Hodder, AQA '']
:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe10153 ''Permanent magnets, page 229, GCSE Combined Science; The Revision Guide, CGP, AQA '']
:[https://www.amazon.co.uk/gp/product/178294558X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=178294558X&linkCode=as2&tag=nrjc-21&linkId=f0dfb66dafcb0c6e9449e7b1a4ae1ac357 ''Permanent magnets, page 92, GCSE Physics; The Revision Guide, CGP, AQA '']
:[https://www.amazon.co.uk/gp/product/1471851362/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851362&linkCode=as2&tag=nrjc-21&linkId=7d78d70a2044ee9982dae010c94af92a ''Permanent magnets, pages 277, GCSE Combined Science Trilogy 2, Hodder, AQA '']
====Edexcel====
:[https://www.amazon.co.uk/gp/product/1292120223/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120223&linkCode=as2&tag=nrjc-21&linkId=068ecf40278c32406a7f1c6e66751417 ''Permanent magnets, page 168, GCSE Physics, Pearson Edexcel '']
:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Permanent magnets, page 267, GCSE Physics, CGP, Edexcel '']
====OCR====
:[https://www.amazon.co.uk/gp/product/1782945695/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945695&linkCode=as2&tag=nrjc-21&linkId=ceafcc80bcad6b6754ee97a0c7ceea53 ''Permanent magnets, page 183, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR '']
:[https://www.amazon.co.uk/gp/product/0198359837/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359837&linkCode=as2&tag=nrjc-21&linkId=3c4229e8b023b2b60768e7ea2307cc6f ''Permanent magnets, pages 120, 122, Gateway GCSE Physics, Oxford, OCR '']