Science Chapter 9
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
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What do Magnets attract?
Magnets attract object made of magnetic materials
What are some examples of magnetic materials?
Iron, Nickel and Cobalt, alloys, stainless steel
What object are made of stainless steels
Spoons,Fork and Knife
What are Permanent magnets made of
Magnetically Hard materials such as steel
What function does Permanent magnets have
They retain their magnetisation once magnetised
What are an example of Magnetically soft material
Iron
What are the disadvantage of Magnetically soft material
they lose their magnetisation easily.
What is the advantage for magnetically soft materials
They are suitable for temporary magnets such as electromagnets
What are Magnetic Poles
Magnetic Poles are the parts of a magnet that exert the greatest force.
What do Magnetic poles occur in
pairs called North(N) and South(S)
Why poles are called north and south
A magnet suspended so that it can rotate freely and horizontally will eventually settle down with one pole facing north and the other facing south The pole is therefore called the ‘north seeking pole’
What colour is north
blue
What colour is south
red
What does alike poles react
They repel
What does unlike poles react
They attract
What is the direction of North Poles
Out
What is the direction of South Poles
In
What is Magnetic Field
Magnetic field is a volume of space where magnetic force is exerted
All magnets are surrounded by magnetic fields. True or Flase
True
How can the shape of a magnetic field be shown
iron fillings or plotting compases
State all the uses of electromagnets
-Scrap yard crane
Explain how electromagnets work
The iron core of the electromagnet is a soft magnetic material. When current flows the iron becomes strongly magnetised and so picks up the scrap iron and steel. When the current is turned off, iron loses its magnetisation and so releases the scrap.
What are Earth’s magnetic field caused by
electric currents flowing through the molten outer core of the Earth
What shape is similiar to the magnetic field
around a bar magnet