magnets and electromagnets

• What are the two poles of a magnet?

  North (N) and South (S)
• What happens when two magnets with the same poles are brought together?

  They repel each other
• What occurs when magnets with different poles are brought close?

  They attract each other
• What materials are attracted to magnets?

  Iron, steel, cobalt, or nickel
• What is a magnetic field?

  Region around a magnet affecting other magnets
• How can a magnetic field be represented?

  By magnetic field lines
• What do magnetic field lines indicate?

  Direction of force on a north pole
• Where do magnetic field lines point?

  From north pole to south pole
• Where is the magnetic field strength greatest?

  At the poles of the magnet
• What does it mean if magnetic field lines are closer together?

  The magnetic field is stronger
• What happens when an electric current flows through a wire?

  It produces a magnetic field around the wire
• How does field strength change with current?

  It increases with greater current
• What shape does the magnetic field around a straight wire take?

  Concentric circles at right angles
• What happens if the direction of the current is reversed?

  The direction of the magnetic field reverses
• What is a permanent magnet?

  A magnet that produces its own magnetic field
• What is an induced magnet?

  An object that becomes magnetic in a field
• What happens to an induced magnet when removed from a magnetic field?

  It loses most or all of its magnetism
• What does a magnetic compass contain?

  A small bar magnet
• How does a compass behave when not near a magnet?

  It aligns with Earth's magnetic field
• What does a compass indicate about the Earth's core?

  That the Earth's core is magnetic
• What is the formula for force on a current-carrying wire?

  Force = magnetic flux density x current x length
• What is the equation for force in a magnetic field?

  $F =$$B l I$
• What is a solenoid?

  A cylindrical coil of wire
• How does sending a current through a solenoid affect its magnetic field?

  It increases the strength of the magnetic field
• What is the shape of the magnetic field around a solenoid?

  Similar to a magnetic field around a bar magnet
• What is true about the magnetic field inside a solenoid?

  It is strong and uniform
• How can the strength of a solenoid's magnetic field be increased?

  By putting an iron core inside it
• How can you determine the north pole of a solenoid?

  Using your right hand with fingers curling current
• What are the advantages of electromagnets?

  Can be turned on/off and adjustable strength
• What is the motor effect?

  Force on a wire in a magnetic field
• What causes the force on a current-carrying wire?

  Interaction between current field and magnetic field
• What happens to the magnet producing the field?

  It experiences an equal-sized force in opposite direction
• How does the direction of the force change?

  If the current or magnetic field direction is reversed
• What does Fleming's left-hand rule help determine?

  The direction of force/motion of the wire
• What are the key terms related to magnets and electromagnets?

  • Attraction
  • Magnetic field
  • Repulsion
  • Electromagnet
  • Permanent
  • Solenoid
  • Induced
• What are the factors affecting the speed of an electric motor?

  • Increase current in the coil
  • Increase strength of the magnetic field
  • Reverse direction of current or magnetic field
• How does Fleming's left-hand rule work?

  • Thumb = Motion
  • First finger = Field
  • Second finger = Current
• What is the relationship between current, magnetic field, and force?

  • Current creates a magnetic field
  • Force is produced when wire is in a magnetic field
  • Direction of force depends on current and field direction