Physics - Topic 13 - Electromagnetic Induction

• What happens when like poles of magnets are brought together?

  They repel each other.
• What happens when like poles of magnets are brought together?

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

  They attract each other.
• What happens when opposite poles of magnets are brought together?

  They attract each other.
• Which materials are typically magnetic?

  Cobalt, Steel, Iron, and Nickel.
• Which materials are typically magnetic?

  Cobalt, Steel, Iron, and Nickel.
• What are the characteristics of permanent magnets?

  • Always magnetic
  • Always have poles
  • Used in speakers, compasses, and electric generators
• What are induced magnets?

  Materials that become magnetic when magnetism is induced.
• What are the characteristics of permanent magnets?

  • Always magnetic
  • Always have poles
  • Used in speakers, compasses, and electric generators
• How can you create a temporary magnet from an induced magnet?

  By stroking it with a permanent magnet.
• What defines induced magnets?

  They are materials that become magnetic only when magnetism is induced.
• How can you create a temporary magnet from an induced magnet?

  By stroking it 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.

  
• What is the behavior of induced magnets after some time or a knock?

  They lose magnetism as the domains move into random positions.

  
• 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.

  
• In which direction do magnetic field lines point?

  From North to South.
• What is the behavior of induced magnets after some time or a knock?

  The domains move into random positions, causing the magnetism to be lost.

  
• How does the strength of a magnetic field change with distance from the magnet?

  It decreases with distance from the magnet.
• In which direction do magnetic field lines point?

  From North to South.
• What do plotting compasses show?

  The direction and shape of a magnetic field at a given point.
• How does magnetic field strength change with distance from the magnet?

  It decreases with distance from the magnet.
• Why does a freely suspended magnetic compass point North?

  Because it aligns itself with the Earth's magnetic field lines.
• What do plotting compasses show?

  The direction and shape of a magnetic field at a given point.
• What is the relationship between Earth's magnetic pole in the north and its geographic pole?

  Earth's magnetic pole in the north is actually a magnetic South Pole.
• What is the nature of Earth's core in relation to magnetism?

  The core is magnetic and creates a large magnetic field around the Earth.
• What does current produce around a wire?

  A magnetic field.
• 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.
• What dictates the direction of the magnetic field produced by a current?

  The "right hand rule."

  
• Why is Earth's magnetic pole in the north actually a magnetic South Pole?

  Because like poles repel, so the compass's north pole aligns with it.
• How can you visualize the direction of the magnetic field around a wire?

  By using plotting compasses on a piece of paper through which the wire is pierced.
• What does current produce around a wire?

  A magnetic field.
• What dictates the direction of the magnetic field produced by a current?

  The "right hand rule."

  
• How does the strength of a magnetic field depend on current size?

  Greater current produces a stronger magnetic field.
• How does the strength of a magnetic field vary with distance from the conductor?

  It becomes weaker with greater distance from the wire.
• How does the direction of current relate to the magnetic field direction?

  Current direction is perpendicular to the magnetic field direction.
• What is the shape of the magnetic field around a solenoid?

  It is similar to that of a bar magnet.
• What are the characteristics of solenoids?

  • Magnetic field shape similar to a bar magnet
  • Coiling wire aligns the field
  • Iron core increases strength
  • Individual coil fields cancel inside
  • Factors affecting strength: current size, length, cross-sectional area, number of turns, soft iron core
• What happens when a wire with current is placed near a magnet?

  The current's magnetic field interacts with the magnet's field.
• What effect does coiling the wire in a solenoid have on the magnetic field?

  It aligns the field and forms a giant single, almost uniform field along the center.
• What is the nature of the force experienced by a wire near a magnet?

  It is equal and opposite to the force felt on the magnet.