7.3 - 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 does the right hand rule help determine?

  The direction of the magnetic field
• If the current flows upwards in a wire, what is the direction of the magnetic field?

  Anti-clockwise around the wire
• What happens to the magnetic field when the current direction is reversed?

  The magnetic field direction also reverses
• How does a flat circular coil differ from two separate wires in terms of magnetic fields?

  It forms a single magnetic field through the center
• What is a solenoid?

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

  It is strong and uniform like a bar magnet
• 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 an electromagnet's magnetic field be reversed?

  By reversing the current direction
• What is the first way to increase an electromagnet's strength?

  Increase the current flowing through it
• What is the second way to increase an electromagnet's strength?

  Increase the number of turns in the coil
• How does the length of the coil affect its strength?

  Shorter coils with more turns are stronger
• What role does an iron core play in an electromagnet?

  It increases the strength of the magnetic field
• What happens to the iron core when the current is turned off?

  It loses its magnetic field
• What are the four ways to increase an electromagnet's strength?

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