Electromagnetism

• What phenomenon does electromagnetism describe?

  Electric currents produce magnetic fields
• How do electric currents affect magnetic fields in wires?

  They produce concentric circles around the wire
• What happens to the magnetic field strength near a wire?

  It is strongest closest to the wire
• What does the direction of the magnetic field depend on?

  The direction of the electric current
• What rule helps determine the direction of the magnetic field?

  The right hand rule
• How do you use the right hand rule?

  Thumb points current direction, fingers curl field
• What is the direction of the magnetic field for upward current?

  Anti-clockwise around the wire
• What happens to the magnetic field if the current direction reverses?

  The magnetic field direction also reverses
• How does a flat circular coil affect magnetic fields compared to straight wires?

  It combines fields into a single magnetic field
• What is a solenoid?

  A coil of wire with many turns
• How does the magnetic field inside a solenoid compare to outside?

  It is strong and uniform inside
• What is an electromagnet?

  A magnet created by electric current
• What happens to an electromagnet when the current is turned off?

  The magnetic field disappears
• How can you reverse the direction of an electromagnet's magnetic field?

  By reversing the current direction
• Why does adding an iron core increase an electromagnet's strength?

  Iron becomes an induced magnet when current flows
• What are the advantages of using electromagnets over permanent magnets?

  • Can be turned on and off
  • Direction of magnetic field can be reversed
  • Strength can be adjusted by current
  • Can be made stronger with iron core