Magnetism and electromagnetism

• What is an alternator?


  A device that generates alternating current using the generator effect
• What happens when opposite poles of magnets are brought together?


  They experience a force of attraction towards each other
• What is generated around a current-carrying wire?


  A magnetic field
• What factors affect the strength of the magnetic field around a wire?


  The magnitude of the current and the distance from the wire
• What is a dynamo?


  A device that generates direct current using the generator effect
• How does an electric motor operate?


  A current-carrying coil in a magnetic field experiences forces causing rotation
• What is an electromagnet?


  A solenoid with an iron core
• What does Fleming’s Left-Hand Rule help determine?


  The orientation of force, current, and magnetic field in a current-carrying wire
• What is the generator effect?


  Induction of potential difference due to relative motion between a conductor and a magnetic field
• What is an induced magnet?


  A material that becomes a magnet in an existing magnetic field but loses magnetism quickly
• What does a magnetic compass contain?


  A small bar magnet
• What do magnetic field lines represent?


  The strength and direction of a magnetic field
• What are magnetic materials?


  Iron, steel, cobalt, and nickel
• Where are the magnetic poles located on a magnet?


  At the regions where the magnetic forces are strongest
• What is the function of a microphone?


  To convert sound wave pressure variations into electrical current variations
• What is the motor effect?


  A force experienced by a current-carrying wire in a magnetic field
• What is a permanent magnet?


  A magnet that produces its own magnetic field
• What happens when like poles of magnets are brought together?


  They experience a force of repulsion
• What is a solenoid?


  A wire wrapped into the shape of a coil
• How can the magnetic field strength of a solenoid be increased?


  By adding an iron core
• What is a step-down transformer?


  A transformer with a smaller potential difference in the secondary coil than in the primary coil
• What is a step-up transformer?


  A transformer with a larger potential difference in the secondary coil than in the primary coil
• What is the unit of magnetic flux density?

  Tesla
• What is the purpose of a transformer?


  To change the potential difference in electrical circuits
• What are the key components of a transformer?


  • An iron core
  • A primary coil of wire
  • A secondary coil of wire
• What are the differences between step-up and step-down transformers?


  • Step-up transformer: larger potential difference in secondary coil
  • Step-down transformer: smaller potential difference in secondary coil
• What are the two types of poles in a magnet?


  North and South Poles
• What happens when two same poles of magnets are brought close together?


  They repel each other
• What occurs when opposite poles of magnets are brought together?

  They attract each other
• What are permanent magnets?

  Magnets that are always magnetic and always have poles
• What are induced magnets?

  Materials that are magnetic but do not have fixed poles
• How can induced magnets be made into temporary magnets?


  By stroking them with a permanent magnet
• What happens to the domains in a material when it is stroked with a permanent magnet?

  They align in the same direction, creating a temporary magnet
• Which materials can become induced magnets?


  Iron, Nickel, and Cobalt
• In a magnetic field, where do the field lines point?


  From North to South
• How does the strength of a magnetic field change with distance from the magnet?


  It decreases with distance from the magnet
• What direction do magnetic field lines point at any point in the field?


  They point to the south pole and away from the north pole
• How can plotting compasses be used in relation to magnetic fields?


  They show the direction of the magnetic field at a certain point
• What is the Earth's core's role in magnetism?

  The core is magnetic and creates a large magnetic field around the Earth
• How does a freely suspended magnetic compass behave in relation to Earth's magnetic field?

  It aligns itself with the Earth's field lines and points North