6.2 Magnetic Flux Density Flashcards
When is a force exerted in a magnetic field?
When magnetic fields interact.
Why do lines that are closer mean the force that will be exerted will be greater?
As the magnetic field strength would be greater due to lines being closer, meaning the force will also be greater.
What is the magnetic flux density?
the force on 1m of wire carrying current of 1A at right angles to magnetic field.
What happens if current supplied is parallel to magnetic field lines?
No force is exerted.
What happens if current supplied is perpendicular to magnetic field lines?
Max force is exerted/
What do we have to do when current supplied is e.g. at an angle of 30 to horizontal?
We have to use trigonometry to work out the force acting in the perpendicular component to magnetic field.
What do we use to work out force/motion , direction of current , direction of field of interacting magnetic components?
Flemings Left Hand Rule
What does the thumb represent in the flemings left hand rule?
The motion/direction of force
What does the first finger represent in flemings left hand rule?
Direction of the magnetic field.
What does the second finger represent in flemings left hand rule?
The direction of conventional current?
What is the direction of current when electrons are the charge carriers?
Opposite to the direction shown by the second finger in fleming’s left hand rule.
Is magnetic flux density a vector or a scalar?
vector
what is the unit of magnetic flux density
T - tesla
or
NA^-1m^-1
What happens when a current carrying wire is placed within another magnetic field. How do we work out the directions?
It will experience a force. Using flemings left hand rule.
What does the force exerted on magnetic materials when their magnetic fields interact is proportional to?
force is proportional to current x length of wire
What is the equation for force? bil
What does each letter represent?
F = bil F = force (N) b = magnetic flux density I = current(A) L = length (m)
In the F = BIL there is usually a suffix under the B , what does it represent?
That the wire carrying the current must be perpendicular to the direction of the magnetic field.
When taking angles into account, what does the f = bil equation become?
F = BIL sinx
Except straight conductors what else can experiance a force in the magnetic field?
Charged particles that are moving
What is the equation for force of a charged moving particle in magnetic field? What does each symbol represent?
F = BQV f = force b = magnetic flux density Q = charge v = velocity
When taking angles into consideration what does f = bqv become?
F = BQVsinx
Since the magnetic field is always perpendicular to direction of travel for a charged particle what condition do we get from this?
Circular motion
Why does circular motion happen?
The velocity of the particle keeps changing (accelerating) as it is attracted to the centre where magnetic field is. So the force will also act towards the centre.
What equation can we use to work out the distance from centre that a charged particle is orbiting.
mv/BQsinx = r
