Introduction to Magnetism Magnetism is a fundamental force of nature that arises from the motion of electric charges. There are two main types of magnets: perma...
Magnetism is a fundamental force of nature that arises from the motion of electric charges. There are two main types of magnets: permanent magnets and induced (electromagnets). Permanent magnets, like bar magnets, produce their own persistent magnetic fields. Induced magnets, such as those in motors and generators, produce magnetic fields through the flow of electric current.
A magnetic field is a region of space where a magnetic force acts. It can be visualized by plotting magnetic field lines, which show the direction of the magnetic force. The Earth itself acts as a giant bar magnet, with a magnetic field surrounding it.
Electromagnetism is the study of the interactions between electric currents and magnetic fields. When an electric current flows through a wire, it creates a magnetic field around the wire. This principle is known as the motor effect.
The strength of the magnetic field around a current-carrying wire can be determined using Fleming's Left-Hand Rule: F = BIL, where F is the force, B is the magnetic field strength, I is the current, and L is the length of the wire.
Electromagnetic induction is the process of generating an electric current in a conductor by changing the magnetic flux through the conductor. This is the principle behind generators and transformers.
In a generator, a coil of wire rotates within a magnetic field, inducing a current in the wire. In a transformer, changing magnetic fields in the primary coil induce a changing magnetic field in the secondary coil, inducing a different voltage.
For more details on these topics, refer to BBC Bitesize GCSE Physics: Magnetism and Electromagnetism and consult your exam board's specification.