Physics- magnetism and electromagnetism

• What are the two poles of a magnet?

  North and south poles
• What do magnets produce in their vicinity?

  A magnetic field
• What materials experience a non-contact force in a magnetic field?

  Iron, steel, nickel, and cobalt
• How can you visually represent a magnetic field?

  By drawing magnetic field lines
• In which direction do magnetic field lines go?

  From north to south
• What does the proximity of magnetic field lines indicate?

  The strength of the magnetic field
• Where is the magnetic field strongest on a magnet?

  At the poles of the magnet
• What type of force is always present between a magnet and a magnetic material?

  Attractive force
• What happens when two like poles of a magnet are brought close together?

  They repel each other
• What happens when two unlike poles of a magnet are brought close together?

  They attract each other
• What is inside a compass?

  A tiny bar magnet
• Why does a compass point north when not near a magnet?

  Because of Earth's magnetic field
• What are the two types of magnets?

  Permanent magnets and induced magnets
• What do permanent magnets do?

  Produce their own magnetic field
• What happens to induced magnets when the magnetic field is removed?

  They quickly lose their magnetism
• How can the strength of a magnetic field around a wire be increased?

  By wrapping the wire into a solenoid
• What shape does the magnetic field around a wire take?

  Concentric circles
• What does the right-hand thumb rule help determine?

  The direction of the magnetic field
• What happens to the magnetic field strength as the distance from the wire increases?

  The field becomes weaker
• What is a solenoid?

  A coil of wire
• What happens to the magnetic field inside a solenoid?

  It is strong and uniform
• How does the magnetic field outside a solenoid compare to that of a bar magnet?

  It resembles the field of a bar magnet
• What is an electromagnet?

  A solenoid with an iron core
• What happens to the magnetic field of an electromagnet when the current stops?

  The magnetic field disappears
• What is the motor effect?

  Force on a current-carrying wire in a magnetic field
• At what angle must a wire be positioned to experience the full force in a magnetic field?

  At 90° to the magnetic field
• What happens to the force on a wire running parallel to a magnetic field?

  It experiences no force
• How can the direction of the force on a current-carrying wire be determined?

  Using Fleming's left-hand rule
• What does Fleming's left-hand rule indicate?

  The direction of force, current, and field
• What happens to the coil in a basic DC motor?

  It rotates due to forces acting on it
• What is the purpose of the split-ring commutator in a motor?

  To keep the motor rotating in the same direction
• How can the direction of a motor be reversed?

  By reversing the current or magnetic poles
• What factors can increase the speed of a motor?

  Increasing current, turns, or magnetic flux density
• How can you determine the direction of rotation of a coil in a motor?

  Using Fleming's left-hand rule
• What does the right-hand rule help determine in electromagnetism?

  The direction of the magnetic field
• What are the key concepts of magnetism?

  • Magnets have north and south poles.
  • They produce magnetic fields affecting magnetic materials.
  • Magnetic field lines indicate strength and direction.
  • Forces between magnets can be attractive or repulsive.
  • Compasses indicate magnetic field direction.
  • Permanent and induced magnets have different properties.
  • Electromagnets can be turned on and off with current.
  • The motor effect involves forces on current-carrying wires.
• What are the factors affecting the force on a conductor in a magnetic field?

  • Magnetic flux density (strength of the field)
  • Size of the current through the conductor
  • Length of the conductor in the magnetic field
• What are the components of a basic DC motor?

  • Coil of wire carrying current
  • Magnetic field from magnets
  • Split-ring commutator for direction control
  • Forces acting on the coil causing rotation