What is the difference between bar magnets and electromagnets?
Electromagnets are made from current-carrying wire coiled into a solenoid. Their magnetic field can be turned 'on' and 'off'.
Bar magnets are made of materials like iron that stay magnetised. Their magnetic field is always 'on'.
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What are the three main ways to increase the strength of an electromagnet?
1. More current - Increasing the electrical current produces a stronger magnetic field.
2. More turns - Adding more wire loops amplifies the magnetic field.
3. Soft iron core - Inserting an iron core concentrates and enhances the magnetic field.
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Why must the core of an electromagnet be made of soft iron?
The core must be made of soft iron which magnetises and demagnetises easily. This allows the electromagnet to be turned on and off.
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How does a simple electric motor work?
1. A loop of wire is placed in a magnetic field.
2. When current flows through the wire loop, it creates its own magnetic field.
3. The interaction between magnetic fields produces forces causing the wire loop to spin.
4. This demonstrates the motor effect converting electric energy into movement.
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