Electromagnetism

• Electromagnetism

  When an electrical current flows through a wire, a magnetic field is produced
• How can you work out the direction of the magnetic field using a diagram

  Point thumb along direction of current and the direction your fingers curl is the direction of the magnetic field lines
• For a current carrying wire, how could you increase the strength of the magnetic field

  Increase the current (or voltage)
• For a current carrying wire, how could change the direction of the magnetic field

  Change the direction of the current (or voltage)
• Solenoid

  A coil of wire with a strong uniform magnetic field inside it
• Electromagnet

  A solenoid with an iron core inside

  The magnetic field can be turned on or off by turning the circuit on or off
• Why do we add a soft iron core to solenoids

  The iron core increases the strength of the solenoid‘s magnetic field
• 4 ways to increase the strength of a solenoid

  Increase the current

  Increase the number of turns in the solenoid, while keeping the length the same

  Reduce the length of the solenoid while keeping the number of turns the same

  Add a soft iron core