Magnets Flashcards
Which way do magnetic field lines point?
North to south
What is magnetic flux density?
The force on 1m of wire carrying a current of 1A at right angles to the magnetic field
What is 1 Tesla?
Tue flux density that produces a force of 1N in a wire of length 1m with 1A at right angles to the magnetic field
What shape path do charged particles follow we they enter at right angles to the magnetic field?
Circle, because force is always directed towards Tue centre of rotation
What is faraday’s law?
The induced EMF is directly proportional to the rate of change of flux linkage
What is lenz’s law?
The induced EMF is in such a direction as to oppose the change that caused it
What does the gradient of a flux linkage against time graph represent?
Induced EMF
What does Vrms represent?
The root mean square of the peak voltage. Which tells you The equivalent dc voltage to deliver the same amount of power
what causes inefficiencies in transformers and how can this be improved?
Flux leakage- use iron core
Eddy currents- use laminated core
Resistance- use thick copper wire
Heating the wire- ventilate the wire
What’s the equation for peak power transferred?
Ppeak = Vo X Io
What’s the equation for mean power transferred?
Pmean = Vrms X Irms
What is a magnetic field?
An area where a magnet or magnetically susceptible material experiences a force of attraction or repulsion
What is magnetic flux?
The total amount of field lines you cut through with your conductor
What is the change in magnetic flux against time graph
Cos graph
What does the y-gain change?
The vertical division
