Electromagnetism

• What phenomenon does electromagnetism describe?

  It describes how electric currents produce their own magnetic fields.
• How do electric currents affect magnetic fields in wires?

  Electric currents produce concentric circles of magnetic fields around the wire.
• What does the strength of the magnetic field around a wire depend on?

  The strength of the magnetic field depends on the proximity to the wire.
• What rule helps determine the direction of the magnetic field around a wire?

  The right hand rule.
• How do you use the right hand rule to find the direction of the magnetic field?

  Point your thumb in the direction of the current and curl your fingers.
• What is the direction of the magnetic field when the current flows upwards in a wire?

  The magnetic field would be anti-clockwise around the wire.
• What happens to the magnetic field when the current direction in a wire is reversed?

  The direction of the magnetic field also reverses.
• What occurs when two wires with currents in opposite directions are joined together?

  The magnetic fields combine and form a single magnetic field through the center of the coil.
• What is a solenoid?

  A solenoid is a coil of wire with many turns that produces a strong and uniform magnetic field.
• How does the magnetic field of a solenoid compare to that of a bar magnet?

  The magnetic field of a solenoid is similar to that of a bar magnet, with distinct north and south poles.
• What is an electromagnet?

  An electromagnet is a magnet created by electric current flowing through a coil of wire.
• What happens to an electromagnet when the current is turned off?

  The magnetic field disappears when the current is turned off.
• How can the direction of the magnetic field in an electromagnet be reversed?

  By reversing the direction of the current flowing through the wire.
• What are the four ways to increase the strength of an electromagnet?

  Increase current, increase number of turns, decrease length of coil, add an iron core.
• Why does adding an iron core to a solenoid increase its strength?

  Iron becomes an induced magnet when the solenoid is switched on, enhancing the magnetic field.
• What happens to the magnetic field of an iron core when the current is turned off?

  The iron core loses its magnetic field when the current is turned off.
• What are the key characteristics of the magnetic field produced by a solenoid?

  • Strong and uniform magnetic field
  • Similar to a bar magnet
  • Distinct north and south poles
• What are the advantages of using electromagnets over permanent magnets?

  • Electromagnets can be turned on and off.
  • The strength can be adjusted by changing the current.
  • The direction of the magnetic field can be reversed.