Magnetic Fields

• Fleming's Left Hand Rule

  The force on a wire is always perpendicular to the magnetic field and conventional current
• Flux is the amount of field lines "flowing" through an area
• A Tesla is the field strength that causes 1m of wire carrying 1A of current to experience 1N of force
• Hall Voltage

  • When a magnetic field is applied across a conductor, the electrons will experience a force
  • The electrons are moved to one side, creating a potential difference
  • Placing a voltmeter on the edges of the conductor will detect a small voltage
• A solenoid is a long piece of wire wound into a coil
• Solenoids create a uniform magnetic field when a current is passed through the wire. Adding an iron core increases the field strength
• Moving Charges:

  • Particles of different masses but the same speed will have different radii in magnetic fields
  • Force is always perpendicular to a moving charge so it will travel in a circle
• Cyclotrons use a uniform magnetic field to accelerate particles into longer and longer paths
• Synchrotrons accelerate particles through a fixed loop using an alternating potential difference across gaps between the Ds. The magnetic field is increased for a particle to maintain the fixed loop