Chapter 23 - Magnetic Fields Flashcards
what do magnetic field lines do
give the shape of a field
indicate strength
indicate direction
uniform magnetic field
equal separation between field lines from north to south
what must field lines always have
direction arrows
right hand rule
thumb points towards north pole
fingers curl in direction of conventional current
magnetic flux density
number of magnetic field lines per unit area of a section, perpendicular to the direction of field
what do closer flux lines represent
greater flux density
magnetic flux measurement
webers
flemings left hand rule
THUMB - direction of force
FIRST FINGER - direction of magnetic field
SECOND FINGER - direction of current
what is a magnetic field
a region where moving charged particles are subject to a magnetic force
what direction do magnetic lines travel
north to south
magnetic flux density unit
Tesla
what is electromagnetic induction
when a current is induced due to a change in the magnetic flux linkage
what is Lenz’s law
that the induced e.m.f is generated in a direction so that it opposes the charge that produced it
what is Faraday’s law
magnitude of induced e.m.f in a conductor is directly proportional to the rate of change of magnetic flux linkage
what is the purpose of step-up transformers
to reduce power losses in the transmission of electrical energy across the national grid
