electromagnets

• 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 shape do the magnetic field lines take around a wire with current?

  Concentric circles
• Where is the magnetic field strongest around a wire?

  Closest to the wire
• What determines the direction of the magnetic field around a wire?

  The direction of the electric current
• How can you remember the direction of the magnetic field using your hand?

  Use the right hand rule
• What does the right hand rule involve?

  Thumb points current direction, fingers curl field direction
• What direction does the magnetic field go for current flowing upwards?

  Anti-clockwise
• What happens to the magnetic field when current flows in the opposite direction?

  The magnetic field direction reverses
• What occurs when two wires are joined to form a coil?

  Magnetic fields stretch and combine
• What is a solenoid?

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

  Strong and uniform inside, weaker outside
• What is an electromagnet?

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

  The magnetic field disappears
• How can the direction of the magnetic field be reversed in an electromagnet?

  By reversing the current direction
• What are the four ways to increase an electromagnet's strength?

  Increase current, turns, decrease length, add iron core
• What effect does adding an iron core have on a solenoid?

  It increases the strength of the magnetic field
• What type of material is iron in the context of electromagnets?

  A soft magnetic material
• What happens to the iron core when the solenoid is switched on?

  It becomes an induced magnet
• What happens to the iron core's magnetism when the current is turned off?

  It loses its magnetic field
• What are the key characteristics of electromagnetism?

  • Electric currents produce magnetic fields
  • Magnetic field direction depends on current direction
  • Electromagnets can be turned on/off
  • Strength can be increased by various methods
• What are the steps to apply the right hand rule?

  1. Curl your right hand into a fist
  2. Point your thumb in the current direction
  3. Fingers curl in the direction of the magnetic field
• How can you increase the strength of an electromagnet?

  • Increase the current
  • Increase the number of turns in the coil
  • Decrease the length of the coil
  • Add an iron core