Magnetism and electromagnetism

• What are the two poles of a magnet called?

  North and South
• Where are magnetic forces strongest on a magnet?

  At the North and South Poles
• What happens when unlike poles of two magnets are brought together?

  They attract each other
• What occurs when like poles of two magnets are brought together?

  They repel each other
• What materials are always attracted to magnets?

  Magnetic materials
• Which elements are commonly found in magnetic materials?

  Iron, nickel, or cobalt
• What are hard magnetic materials?

  Materials that are difficult to magnetize
• What are soft magnetic materials?

  Materials that are easy to magnetize
• Why are soft magnetic materials used in electromagnets?

  They can easily switch magnetism on and off
• What is the process of determining if a material is magnetic?

  Bring it close to a known magnet
• What indicates that a material is a magnet when tested with another magnet?

  If it can repel the known magnet
• What does it mean if a material is only attracted to a magnet?

  It is a magnetic material
• What does it mean if a material is not affected by a magnet?

  It is a non-magnetic material
• What happens when a North Pole is brought near the end of a magnetic bar that attracts?

  It indicates the bar is a magnetic material
• What does it indicate if two magnets repel each other?

  One is a magnet and the other is a North Pole
• What is magnetization?

  The process of inducing magnetism in materials
• How can iron and steel be magnetized?

  By placing them near a strong magnet
• What happens to iron when it is brought near a strong magnet?

  It becomes magnetized but loses magnetism quickly
• What is the effect of stroking a steel bar with a magnet?

  It magnetizes the steel bar more strongly
• What is the result of stroking a steel bar with the North Pole of a magnet?

  One end becomes a South Pole
• What happens when a steel bar is stroked with a South Pole?

  One end becomes a North Pole
• How can a magnetic material be magnetized using direct current?

  By passing current through a coil around it
• What is demagnetization?

  The process that destroys magnetism
• How can a magnet be demagnetized by heating?

  By heating it until it loses magnetism
• What is the effect of hitting a magnet with a hammer?

  It can demagnetize the magnet
• How does alternating current demagnetize a magnet?

  By generating a changing magnetic field
• What defines a magnetic field?

  The region where magnetic materials experience force
• What do magnetic field lines represent?

  The direction and strength of a magnetic field
• How do magnetic field lines run around a magnet?

  From North Pole to South Pole
• What does it indicate when magnetic field lines are close together?

  Strong magnetic field strength
• What does it indicate when magnetic field lines are far apart?

  Weak magnetic field strength
• What is the magnetic field pattern around two magnets with opposite poles?

  Field lines connect between the two poles
• What is the magnetic field pattern around two magnets with the same poles?

  Field lines repel each other
• What is a uniform magnetic field?

  Field lines are parallel and evenly spaced
• What causes the Earth to act as a magnet?

  The iron and nickel in its core
• What direction do Earth's magnetic field lines run?

  From South to North Pole
• Why does a compass needle point to the North Pole?

  It is a magnet attracted to Earth's South Pole
• How can magnetic field lines be plotted using iron filings?

  By sprinkling filings on paper over a magnet
• What happens to the magnetic field lines as the distance from a wire increases?

  They get further apart
• What does the right-hand grip rule help determine?

  The direction of the magnetic field around a wire