Magnetism Flashcards
A magnetic field
Region of space in which magnetic forces can be felt
Magnetic flux density ( not in tables)
Force/( current X length)
Tesla
Unit of magnetic flux density (B). 1B= force of 1 N when 1A flows through a wire of 1m
Weber (Wb)
The unit of magnetic flux. The magnetic flux over an area of 1 m² is 1Wb if placed in a field of magnetic flux density of 1 T
An electromagnet
A solenoid and a soft iron core that becomes magnetised if the current passes through it
Electromagnetic induction
The inducing of an emf by changing the magnetic field in a closed loop
The laws of electromagnetic induction
Faraday’s law and lenz’s law
Faradays law
The size of the induced EMF is proportional to the rate of change of magnetic flux linking the circuit
Lenz’s law
The direction of an induced EMF opposes the change causing it
Mutual induction
Occurs in two adjacent coils when the magnetic field in one coil changes and an EMF is induced in the other
A transformer
A device which changes the value of an alternating voltage
Self induction
A changing magnetic field in a coil induces an emf in the coil itself
