Electromagnetism

• What phenomenon do electric currents produce?

  Magnetic fields
• How do electric currents affect magnetic fields in wires?

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

  Concentric circles
• Where are the magnetic field lines closest together around a wire?

  Near the wire
• What does the direction of the magnetic field depend on?

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

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

  Thumb points current direction, fingers curl field direction
• What is the direction of the magnetic field for current flowing upwards in a wire?

  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 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
• How can the number of turns in a coil affect an electromagnet?

  More turns increase strength
• What happens if you decrease the length of the coil while keeping the number of turns the same?

  The strength of the electromagnet increases
• What material can be added to a solenoid to increase its magnetic field strength?

  An 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 an electromagnet's strength?

  • Increase the current
  • Increase the number of turns in the coil
  • Decrease the length of the coil
  • Add an iron core
• What is the relationship between solenoid turns and magnetic field strength?

  • More turns lead to stronger magnetic fields
  • Densely packed coils enhance strength