Electromagnets (Oxford AQA IGCSE Combined Science Double Award)
Revision Note
Written by: Ann Howell
Reviewed by: Caroline Carroll
Electromagnets
A solenoid can be used as an electromagnet by adding a soft iron core
The iron core will become an induced magnet when current is flowing through the coils
The magnetic field produced by the solenoid and the iron core will create a much stronger magnet overall
The magnetic field produced by the electromagnet can be switched on and off
When the current is flowing there will be a magnetic field produced around the electromagnet
When the current is switched off there will be no magnetic field produced around the electromagnet
Electromagnet diagram
Changing the direction of the current also changes the direction of the magnetic field produced by the iron core
Factors affecting magnetic field strength
The strength of the magnetic field produced around a solenoid can be increased by:
Increasing the size of the current which is flowing through the wire
Increasing the number of coils
Adding an iron core through the centre of the coils
The strength of an electromagnet can be changed by:
Increasing the current to increase the magnetic field produced around the electromagnet
Decreasing the current to decrease the magnetic field produced around the electromagnet
Examiner Tips and Tricks
When trying to figure out how an electromagnetic device works:
Look for a coil or solenoid - this is going to act as an electromagnet
Look for a piece of iron - this will be attracted to the solenoid
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