Electromagnetism

• What phenomenon does electromagnetism describe?

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

  They produce their own magnetic fields around them
• What shape do the magnetic field lines take around a wire with current?

  Concentric circles around the wire
• 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 curling your fingers in the right hand rule indicate?

  The direction of the magnetic field
• 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 shape is formed when two wires are joined to create a coil?

  A flat circular coil
• How do the magnetic fields of a coil interact?

  They combine to form a single magnetic field
• What is a solenoid?

  A coil of wire with many turns
• What is the magnetic field like inside a solenoid?

  Strong and uniform
• How does the magnetic field outside a solenoid compare to that of a bar magnet?

  It resembles the field of a bar magnet
• What happens to an electromagnet when the current is turned off?

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

  By reversing the current direction
• What happens to the magnetic field lines when the current direction is flipped?

  The direction of the field lines flips
• What is one way to increase the strength of an electromagnet?

  Increase the current flowing through it
• How does increasing the number of turns in a coil affect its strength?

  It increases the strength of the electromagnet
• What happens if you decrease the length of the coil while keeping the number of turns the same?

  The strength of the electromagnet increases
• Why do densely packed coils produce stronger solenoids?

  They create a stronger magnetic field
• What material can be added to a solenoid to increase its strength?

  Iron core
• 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 four ways to increase the strength of an electromagnet?

  • Increase the current flowing through the solenoid
  • Increase the number of turns in the coil
  • Decrease the length of the coil
  • Add an iron core to the solenoid