Magnetic Flux Density

• What is a magnetic field?

  A region where a magnetic pole experiences force
• How is a magnetic field created?

  By moving electric charge or permanent magnets
• What are permanent magnets?

  Materials that produce a magnetic field
• What happens with a stationary charge in terms of magnetic fields?

  A stationary charge does not produce a magnetic field
• What is another term for a magnetic field?

  B-field
• How is a magnetic field created around a current-carrying wire?

  Due to the movement of electrons
• How can magnetic fields be observed?

  By the force acting on magnetic materials
• What describes the strength of a magnetic field?

  The density of its flux lines

  
• What is magnetic flux density B defined as?

  The number of flux lines per unit area

  
• In what unit is magnetic flux density measured?

  In teslas (T)
• What is one tesla defined as?

  Flux density causing 1 N on 1 m wire
• How does flux density relate to magnetic field strength?

  Higher density means a stronger magnetic field

  
• What does it indicate when flux lines are closer together?

  It indicates a stronger magnetic field

  
• What does it indicate when flux lines are further apart?

  It indicates a weaker magnetic field
• What is the direction of magnetic flux lines?

  From the north pole to the south pole

  
• What are the key aspects of drawing magnetic field lines?

  • Arrows point out of the north pole
  • Arrows point into the south pole
  • Closer lines indicate stronger fields
  • Further lines indicate weaker fields
  • Lines never cross

  
• Where is the flux density strongest around a bar magnet?

  At the two poles

  
• What is the simplest representation of magnetic flux lines?

  Seen around bar magnets

  
• What should you refer to for tips on magnetic fields in wires?

  The GCSE page on Magnetic Fields in Wires