Electromagnets (Edexcel IGCSE Physics)
Revision Note
Electromagnets
When an electric current flows in a wire it creates a magnetic field around the wire
By winding the wire into a coil we can strengthen the magnetic field by concentrating the field lines
If this wire is wound around a soft magnet, such as an iron, then an electromagnet is made (see the electromagnet diagram below)
The electromagnet is magnetic only when current flows through the wire
Electromagnet diagram
Electromagnets are made up of a coil of wire wrapped around an iron core
The strength of an electromagnet’s magnetic field may be increased by:
Increasing the current in the coil
Adding more turns to the coil
The magnetic field around an electromagnet has the same shape as the one around a bar magnet
The field can be reversed by reversing the direction of the current
However, bar magnets are always magnetic, unlike electromagnets
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