1. AQA Physics Magnetic Fields Section 1 Introduction to Magnetic Fields, Flux and Flux Density

2. Magnetic Fields A magnetic field is a region of space where magnets, magnetic materials and moving charged particles experience forces. A magnetic field can be illustrated using magnetic field lines. Magnetic Field lines: are continuous do not overlap are more dense in number where the magnetic field is stronger move in a direction from North Pole to South Pole It is necessary to sketch both magnetic fields and currents into and out of the plane you are working. In these cases the following symbols are used. It should be trivial to determine whether the symbol refers to a magnetic field or a current by examining the context of the illustration. into the plane out of the plane

3. N S The Magnetic Field due to a Permanent Bar Magnet

4. The Magnetic Field due to an Wire

5. The Magnetic Field due to a Single Coil

6. The Magnetic Field due to a Long Solenoid A solenoid is a coil of wire with many turns. The nature of the flow of current through a solenoid is more easily examined by considering its cross section.

7. The Magnetic Field due to a Long Solenoid A solenoid is a coil of wire with many turns. The nature of the flow of current through a solenoid is more easily examined by considering its cross section.

8. Magnetic Flux Magnetic flux can be loosely considered to be related to the number of magnetic field lines that occupy a certain space. Magnetic flux is given the symbol  and is measured in webers (Wb). As the proximity of magnetic field lines determines the strength of the magnetic field it is useful to define the amount of flux per unit area, the flux density (B): Flux density (B) is measured in webers per square metre (Wbm -2 ). 1 tesla (T) = 1 Wbm -2