Electromagnets

• What is the difference between a magnet and a magnetic material

  A magnetic material is attracted to a magnet and a magnet produces a magnetic field
• Electromagnetism: When a current is passed through a wire, and a magnetic field is created around the wire.
• Describe the magnetic field around a current carrying wire


  A series of concentric circles centred on the wire
• How does the right hand grip rule show the direction of a magnetic field around the wire


  You make a thumbs up fist with your right and and point it in the direction of the current, whichever way your fingers bend round shows the direction of the magnetic field.
• A solenoid: a coil of wire that produces a magnetic field around it.
• How can you use the right hand grip rule to find where north is on a solenoid?

  You curl your fist in the direction of the current and your thumb points to north
• How is the electromagnetism of a solenoid affected when you put something magnetic in the core?

  The electromagnetism increases
• Making an electromagnet practical:

  1. Set the power pack to 4V
  2. Construct a circuit to flow through the nail, wrap 5 turns of wire around the iron nail
  3. See how many paperclips it can pick up when the power pack is turned on and record in a suitable table
  4. Add another 5 turns of wire around the nail and repeat until the nail is full of wire
• What three things can increase the strength of an electromagnet?

  -Increase current

  -Increase number of coils of wire

  -Use a magnetic core
• Why does using a magnetic core increase the strength of an electromagnet?

  Because in a magnetic material the domains all point in different directions which cancel each other out. When a magnetic material is in the presence of a solenoid the domains can be made to point in the same direction which creates a magnetic field. This adds to the magnetic field of the solenoid and makes it stronger.