magnetism and electromagnetism

• What are the two poles of a magnet?

  North pole and south pole
• Where is the magnetic force strongest on a magnet?

  Near the magnet's poles
• What are the rules of magnetism regarding attraction and repulsion?

  • Like poles (N-N or S-S) repel
  • Unlike poles (N-S or S-N) attract
• What type of forces do magnets exert on each other?

  Non-contact forces
• Which materials are considered magnetic?

  Iron, steel, nickel, and cobalt
• What is a permanent magnet?

  A magnet that produces its own magnetic field
• What are key features of a permanent magnet?

  Produces a constant magnetic field
• How does an induced magnet differ from a permanent magnet?

  It only becomes a magnet in a magnetic field
• What happens to induced magnetism when the magnet is removed from the field?

  It is quickly lost
• What happens to iron filings near a bar magnet?

  They become induced magnets
• What can a permanent magnet do?

  • Attract or repel another permanent magnet
  • Attract a magnetic material (not repel)
• How can you show that an object is a permanent magnet?

  By checking if it repels another magnet
• What is a magnetic field?

  The region around a magnet where force acts
• How can a magnetic field be detected?

  Using a magnetic compass
• What does a compass needle point to?

  The direction of the Earth's magnetic field
• How can you map out a magnetic field using plotting compasses?

  1. Place the compass near the magnet on paper
  2. Mark the direction of the needle
  3. Move the compass to different positions
  4. Join the points to show field lines
• Which pole does the needle of a plotting compass point to?

  The south pole of the magnet
• What do magnetic field lines never do?

  Cross each other
• What does the proximity of magnetic field lines indicate?

  The strength of the magnetic field
• What do the arrowheads on magnetic field lines indicate?

  The direction of the force
• From which pole to which pole do the arrowheads point?

  From north pole to south pole
• What happens when a current flows in a wire?

  It creates a circular magnetic field
• How does the magnetic field affect a magnetic compass?

  It can deflect the needle
• Where is the magnetic field stronger in relation to the wire?

  Closer to the wire
• What happens to the magnetic field strength if the current is increased?

  It becomes stronger
• What is the direction of the magnetic field when current flows bottom to top?

  Rotates anticlockwise
• What is the direction of the magnetic field when current flows top to bottom?

  Rotates clockwise
• What is a solenoid and its magnetic field characteristics?

  • A solenoid is a coiled wire.
  • It creates a magnetic field similar to a bar magnet.
  • The field inside is strong and uniform.
  • Small fields from each coil combine for a stronger field.
• What is an electromagnet?

  A solenoid with an iron core
• How does an iron core affect a solenoid's magnetic field?

  It increases the magnetic field strength
• What is a simple way to create an electromagnet?

  Coil wire around an iron nail
• Where are electromagnets commonly used?

  In electric bells and remote door locks
• What does a wire carrying a current create?

  A magnetic field
• What is the motor effect?

  Force pushing wire at right angles
• What is the equation to calculate the force on a wire?

  Force = magnetic flux density × current × length
• What does F represent in the force equation?

  Force in newtons (N)
• What does B represent in the force equation?

  Magnetic flux density in tesla (T)
• What does I represent in the force equation?

  Current in amperes (A)
• What does L represent in the force equation?

  Length in metres (m)
• When does the force on a wire increase?

  When current or magnetic field strength increases