A current-carrying conductor produces its own magnetic field
When interacting with an external magnetic field, it therefore will experience a force
A current-carrying conductor will only experience a force if the current through it is perpendicular to the direction of the magnetic field lines
A simple situation would be a copper rod placed within a uniform magnetic field
When current is passed through the copper rod, it experiences a force which makes it move
This phenomenon is sometimes referred to as 'the motor effect'
The direction of the force is determined by Fleming's left-hand rule
A current-carrying conductor will only experience a force if the current through it is perpendicular to the direction of the magnetic field lines
A) uniform
B) electrons
C) copper
D) current
E) copper
F) force
G) current
H) on
Two ways to reverse the direction of the force (and therefore, the copper rod) are by reversing:
The direction of the current
The direction of the magnetic field
The direction of the force (aka the thrust) on a current carrying wire depends on the direction of the current and the direction of the magnetic field
All three will be perpendicular to each other
This means that sometimes the force could appear to be acting either into or out of the page
The direction of the force (or thrust) can be worked out by using Fleming's left-hand rule:
A) thrust
B) field
C) current
How to find things using the Fleming LH
Step 1: Determine the direction of the magnetic field
Start by pointing your First Finger in the direction of the (magnetic) Field.
Step 2: Determine the direction of the current
Now rotate your hand around the first finger so that the seCond finger points in the direction of the Current
Step 3: Determine the direction of the force
The THumb will now be pointing in the direction of the THrust (the force)Therefore, this will be the direction in which the wire will move
Remember that the magnetic field is always in the direction from North to South and current is always in the direction of a positive terminal to a negative terminal.
Feel free to use Fleming's left hand rule in your exam, just don't make it too distracting for other students!
When a current-carrying wire is placed in a magnetic field, it will experience a force if the wire is perpendicular
This is because the magnetic field exerts a force on each individual electron flowing through the wire
When a charged particle passes through a magnetic field, the field can exert a force on the particle, causing it to deflect
The force is always at 90 degrees to both the direction of travel and the magnetic field lines
The direction can be worked out by using Fleming's left-hand rule
In the case of a electron in a magneticfield the second finger points in the opposite direction to the direction of motion
Conventionalcurrent is said to flow opposite to the direction of flow of electrons
The finger represents current
An alternative is to use the right hand to work out directions for charged particles
In the case of a electron in a magnetic field the second finger points in the opposite direction to the direction of motion
A) electron
If the electron particle is travelling parallel to the field lines:
It will experience no force
If the electron particle is travelling perpendicular to the field lines:
It will experience the maximum force
If the electron particle is travelling at an angle to the field lines:
It will experience a small force
Remember that the direction of current is the direction of positive charged. Therefore, if a particle has a negative charge (such as an electron), then the second finger (current) must point in the opposite direction to its direction of travel.
The left-hand rule can be applied to any charged particles, but in the IGCSE exam questions are likely to stick to electrons.
If 2 parallel wires have opposite travelling currents, magnetic field generated between the two is the same decision
wires repel eachother - magnets with like poles repel
Wire moves because magnetic field of permanent magnet reacts with magnetic field aka motor effect
Current-carrying conductor - conducts anything with current
If 2 parallel wires have opposite travelling currents, magnetic field generated between the 2 is the same direction
wires repel eachother - magnets with like poles repel
Wires move because magnetic field of the permanent magnet reacts aka motor effect
Current-carrying conductor - conducts anything with current
3-way switch - one way for one circuit, other war for another circuit
middle = open
Circuit in series:
same → repelling
Circuit in parallel
opposing → attractionn
Motor effect - LH rule
middle → current
thumb → movement
index → magnetic field
Force factors - magnitude of the force depends on the current, strength of magnetic field, length of the wire, angle between the lines of the force of the field and current direction
Force is:
greatest when wire is at 90 degrees to the magnetic field
0 when wire is parallel to the magnetic field
If a beam of charged particles pass through a magnetic field, there is a force on it, just like current in the wire
What will happen to the turning force of a coil if you decrease the current passing through?
Decreasing the current passing through a coil immersed in a magnetic field will decrease the turning force (torque) on the coil
The force experienced by current-carrying wires in magnetic fields is caused by