Magnetic fields

• Magnetic fields can be visualized using magnetic field lines, which indicate the direction and strength of the field at different points.
• The size of the force acting on a current-carrying wire is given by the equation: F=BIl sinθ, where B is the magnetic field strength in Tesla, T.
• The force on a current-carrying wire will be greatest when the field and the current are perpendicular, i.e. sinθ=1, but when they are not perpendicular; θ, the angle between the direction of field and the current are used in the equation.
• The force on individual charged particles can be calculated using the equation: F=Bqv sinθ, where v is the velocity of the moving particle and q is its charge.
• Electrons are commonly the charges involved, therefore q=-1.6 × 10-19 C, but other charged particles will obey the same equation.
• The direction of the force on a charged particle can be determined using Flemings left-hand Rule, in the same way as the force on a current carrying wire.
• The direction of the current will be the same as the direction of movement of the positively charged particles.
• The direction of current will be in the opposite direction to the movement of electrons, as they are negatively charged.