4.1.6

Electromagnets

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Permanent Magnets and Electromagnets

You can create a magnet using a permanent magnet or by passing an electric current through a coil of wire (electromagnet).

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Electromagnets

  • An electromagnet is made from a cylindrical coil of wire that has an electric current passing through it.
  • An electromagnet is only magnetic when there is an electrical current flowing through it.
  • When the electric current is switched off, the wire immediately loses its magnetism (is demagnetised).
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Permanent magnets

  • Permanent magnets are usually made from steel.
  • These materials have strong magnetic fields and it is hard to remove their magnetism.

Increasing the Strength of an Electromagnet

There are 3 ways to increase the strength of an electromagnet:

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Iron core

  • To increase the strength of an electromagnet you can place a soft iron core inside the solenoid (cylindrical coil of wire).
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More coils

  • To increase the strength of an electromagnet you can increase the number of coils of wire.
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Higher electric current

  • To increase the strength of an electromagnet you can increase the electric current flowing through the coils.

Jump to other topics

1Motion, Forces & Energy

1.1Physical Quantities & Measurement Techniques

1.2Motion

1.3Mass & Weight

1.4Density

1.5Forces: Effects of Forces

1.6Forces: Turning Effects of Forces

1.7Forces: Centre of Gravity

1.8Momentum

1.9Energy, Work, & Power: Energy

1.10Energy, Work & Power: Work

1.11Energy, Work & Power: Energy Resources

1.12Energy, Work & Power: Power

1.13Pressure

2Thermal Physics

3Waves

4Electricity & Magnetism

4.1Simple Phenomena of Magnetism

4.2Electrical Quantities: Electric Charge

4.3Electrical Quantities: Electric Current

4.4Electromotive Force & Potential Difference

4.5Electrical Quantities: Resistance

4.6Electrical Energy & Electrical Power

4.7Electric Circuits: Circuit Diagrams & Components

4.8Electric Circuits: Series & Parallel Circuits

4.9Electric Circuits: Action & Use

4.10Electrical Safety

4.11Electromagnetic Effects: Electromagnetic Induction

4.12Electromagnetic Effects: The A.C. Generator

4.13Magnetic Effect of a Current

4.14Force on a Current-Carrying Conductor

4.15Electromagnetic Effects: The D.C. Motor

4.16Electromagnetic Effects: The Transformer

5Nuclear Physics

6Space Physics

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