Cards (11)

  • Magnetic force is a non-contact force that is exerted around a magnet, in a magnetic field. It can be either push(repulsion) or pull(attraction).
  • Induced magnetism is a temporary magnetism acquired by a magnetic material when it is placed near a magnet
  • The strength of the induced magnetism depends on how close the object is to the permanent magnet.
  • Magnetic materials : Cobalt, Nickel, Iron and steel
  • When you draw a magnetic field, the arrows are always from north to south
  • How to draw a magnetic fields
    1. Place a bar magnet and draw around it.
    2. Place the plotting compass at the pole of the bar magnet and make a dot where the red tip indicates.
    3. Move the compass tail to the new dot and repeat it until you reach the other pole.
    4. Draw a line through the dots.
  • Magnetic field(force) is the strongest at the poles
  • Electromagnet is a coil of insulated wire(copper, also called a solenoid) wrapped around an iron core which becomes magnetic when there is a current(flow of electrons) in the wire.
  • Unlike permanent magnet, electromagnet can be switched on & off
  • What happens when you turn an electromagnet on?
    If you turn the electromagnet on, there is a current in the coil. A magnetic force is produced around the coil, and the iron core becomes magnetized due to induced magnetism. So, the magnetic materials are attracted to the electromagnet.
  • How to increase the strength of an electromagnet?
    1. Use a bigger current
    2. Use an iron core
    3. Make more turns of wire on your solenoid.