P7 - Magnetism Flashcards
Which direction do field lines always point?
North - South
True or false: induced magnets always repel
False - they always attract
What is a solenoid?
A coil of wire
What happens to a current-carrying wire when placed in a magnetic field?
It moves
What does the movement of a current carrying wire in a magnetic field lead to?
The motor effect
What does a split ring commutator do?
Keep the rotation of the motor going in the same direction.
What is the equation for the force on a wire exposed to a magnetic field?
F=BIL
What does the right hand thumb rule tell you?
- Which way the magnetic field is going around the wire (clockwise or anticlockwise) - Which way the current is moving through the wire.
What does the left hand rule tell you?
- The motion of the wire in a magnetic field,
- The direction of the field lines (which side is North/South)
- The current
What do transformers do?
Change the potential difference in alternating current.
What is the generator effect?
The induction of a PD in a wire in a magnetic field.
How does the wire induce PD in the generator effect?
Movement f the wire causing cutting of the field lines.
How can you increase the size of the PD induced by the wire?
- Increase the speed at which you move the wire through the magnetic field
- Increase the strength of the magnetic field
