Magnetism and Electromagnetism Flashcards
Definition of magnetism
Study of the behaviour of magnets
Properties of magnets
Like pole repel
Attract magnetic materials such as - iron, nickel, cobalt and their alloys
Poles where force is concentrated
Freely suspended magent rests in North-South direction
Electrical method for demagnetisation
A.C. supply connected to solenoid. Magnet is placed inside the solenoid then slowly withdrawn away in the east-west direction
Stroking method for demagnetisation
Induction method for demagnetisation
Magnetic Field
Moves from North to South
Field lines never overlap
Strong where lines are close together
Electromagnet
Temporary magent that only works when supplied with a current
Solenoid
A cylindrical coild made by winding several turns of copper wire
How to increase electromagnetic strength
Increase current
Increase turns of coil
Change shape of core to a horse shoe
Fleming’s left hand rule
Predict direction of the force
Left first finger - North South (direction of magnetic field)
Left thumb - direction of force/motion
Left middle finger - Direction of current
Factors affecting force
Current changes, force changes
Poles change, current changes
