Magnetic Fields
Give 2 ways a magnetic field can be created
- Permanent magnet
- Current carrying conductor
Give features of a magnetic field
- Closer field lines, stronger magnetic field
- Equally spaced & parallel lined show a uniform field
- Arrows show the direction the north pole wolud move
Define a 'solenoid'
A coil of wire
What happens when a current carrying wire is placed into a magnetic field?
It experiences a force perpendicular to the magnetic field lines & current
Define 'Magnetic Flux Density'
The force per unit length per unit current on a current carrying wire in a magnetic field
Give a formula linking force & magnetic flux density
F = BILSinθ
F = Force
B = Magnetic flux density
I = Current
L = Length of wire in the field
Give factors affecting magnetic field strength of a solenoid
- Adding an iron core (or a more iron-rich core)
- Adding more coils to the solenoid
Why does a charged particle move in a circular motion in a magnetic field
The force acting on the charged particle is always perpendicular to the motion & velocity of the particle
What does a charged particle moving in a circular motion in a magnetic field tell you about the magnetic force.
That the magnetic force is a centripetal force
What does sinθ represent in the F = BILSinθ equation
The angle between the current carrying conductor and the magnetic field lines
Give the formula linking Force, Magnetic Flux Density & Charge
F = BQvSinθ
F = Force
B = Magnetic Flux density
Q = Charge
v = Velocity
What is a velocity selector?
A device consisting of perpendicular electric and magnetic field lines used to separate out charged particles of a certain velocity from a stream of accelerated particles moving at a range of speeds
Give the equated eqution for electric and magnetic force
EQ = BQv
E = Electric Field Strength
Q = charge
B = Magnetic Flux Density
v = Velocity
What happens if EQ > BQv in a velocity selector
The charged particle slows down & will travel in the direction of the Electric force acting on the particle
What happens if EQ < BQv in a velocity selector
The charged particle will travel faster and travel in the direction the magnetic force acts on it
Where do charged particles go if the pass throuh the velocity selectors gap
Into a collimator
What assumption can you make about a magnetic field inside a solenoid
That is a uniform field