MAGNETIC FIELDS Flashcards
define magnetic field
the region around a permanent magnet or moving charge, in which another magnetic body will feel a force
what is the right hand rule
a way to determine the direction of the magnetic field lines. with thumb pointed in the direction of the flowing charges.
what is magnetic flux
ø=BaCosθ
where ø is the flux and B is the flux density and θ is the angle between the field lines and the normal to the surface
what is magnetic flux density
the measure of the strength of a magnetic field
defined through equation
F=BILsinθ
F is the force on the wire, B is the MFD, I is the current, L is the length of wire in the magnetic field and θ is the angle between the wire and the magnetic field lines
what is the motor effect
when an electric current flows through a wire, a magnetic field will be present. If the wire is placed in a uniform magnetic field perpendicularly then there will be a force, depending on the direction of the wire or the field. as the field around the wire is concentric circles then one side of the wire will be going the same direction as the field of the magnets and the other will go the opposite way, and since fields are vectors, one side will cancel out and the other will add together to create a force.
what four properties does a force on a current carrying wire depend on
-current
-length
-flux
-θ
F=bilsinθ
what is the equation F=BQv used for?
force on a charged particle in a uniform magnetic field.
t=Q/i, t=L/v
Q/i=L/v
i=Qv/L
f=BIL so F=BQV
how can we link centripetal force with force on a charged particle in a uniform magnetic field
f=mv^2/r
f=BQv
BQv=mv^2/r
r=MV/BQ
how do we calculate the force acting on charged particles in an electric field
F=QE
E is the electric field strength.
what equation can we use to link charged particles moving in electric and magnetic fields.
think about previous equations
F=BQv F=QE
BQv=QE
v=E/B
what is electro magnetic induction
the process of inducing an emf in a conductor when there is a change in magnetic flux across a conductor
what is magnetic flux linkage
the product of the magnetic flux through the coil and the number of turns on the coil. =Nø- weber turns
what is a transformer
a device that can either increase or decrease the size of an alternating voltage with little loss of power.
efficiency is the ratio of
