What direction do Magentic Field lines follow
North to South
When is a Magnetic Field induced
When current passes through a wire
What is Magnetix Flux Density
The force per unit charge and length of a magnetic field, it is a measure of the strength of the field
What is the Definiton of a Tesla
One Tesla is defined as a force of 1 N on 1 metre of wire carrying 1 A of current perpendicular to a magnetic field
What is the equation of the force of a wire when it is placed into a magnetic field
F = B x I x L x Sin (θ)
Force (N) = Magnetic Fluex Density (T) x Current (A) x Sin( the angle from the field)
When is the force of a wire placed in a magnetic field at it’s strongest
When the field is perpendicular to the current
How do you find the direction of a force excerted on a wire
Flemming’s Left Hand Rule
- F - Force
- B - Magnetic Flux Density
- I - Conventional Current (opposite direction to electron flow)
Describe the Magnetic Field Lines of different Bar Magnets
Why is a force exerted on a current-carrying wire
- A force acts on charged particles moving in a magnetic field
- Therefore because the wire contains moving electrons, which are negatively charged, a force is excerted on the wire
What is the Equation of the Force excerted on a particle when it is moving in a Magentic Field
F = B x Q x V
Force (N) = Magnetic Flux Density(T) x Charge (C) x Velocity (m/s)
Which direction is the force excerted on a particle when it is moving in a magnetic field
- The force exerted is always perpendicular to the motion of travel
- This causes the charged particles to follow a circular path when in the magnetic field
- Because the force induced by the magnetic field acts as a centripetal force
How would you find the radius of a particle’s circular path when it is inside a magentic field
- Combine the formulas of Centripetal Force and Magnetic Force on a charged particle
- F = BQV (Magnetic Force)
- F = mv2 / r (Centripetal Force)
- QVB = mv2 / r
- r = MV / BQ
What is an application of the circular deflection of charged particles in a magnetic field
- A cyclotron (a particle accelerator)
- Cyclotrons produce ion beams for radiotherapy, and radioactive tracers
Describe how a Cyclotron works
- A cyclotron is formed of two semi-circular electrodes called “Dees”
- The “Dees” have a uniform magnetic field acting perpendicular to the plane of the electrodes, and a high frequency alternating voltage applied between the electrodes
- The charged particles move from the centre of one of the electrodes, and are deflected in a circular path by the magnetic field
- Once the particles reach the edge of the electrode they begin to move across the gap between the electrodes, where they are accelerated by the electric field, meaning the radius of their circular path will increase as they move through the second electrode
- When the particles reach the gap again, the alternating electric field changes direction allowing the particles to be accelerated again
- This process repeats several times until the required speed is reached by the particles and they exit the cyclotron
What is Magnetic Flux
The magnetic field passing through a given area, when the field is perpendicular to the area
What is the Magnetic flux linkage
The magnetic flux multiplied by the number of turns of a coil
What is the Equation for the Magnetic Flux Linkage
Nϕ = B x A x N x Cos(θ)
Magetic Flux Linkage (Wb) = Magnetix Flux Density (T) x Area (M2) x Number of Turns x Cos (The angle from the normal)
