last electromagentism quix Flashcards
what was Ampres experiment
what happens when you put current carrying conductors next to each other
Right hand rule 1
thumb in direction of current. curl in finger show direction of mf
Right hand rule 2
thumb points towards north, fingers are direction of current
Right hand rule 3
4 fingers finger point towards the mf lines, thumb points to current and palm faces magnetic force direction
what is an electromagnetic field created from
created from a current passing through a wire
what is the problem with DC motors without split rings
they wont have a continous rotation in one direction without split rings because split rings keep one side positive by their function which keeps the downwards force of a mf on one side and the upwards on another creating rotation.
what keeps the wires rotation or whatever when no magnetic field or electricity
inertia
what are the factors that affect electromagnetic induction
1) a coil produces a greater current than a straight conductor
2) strength of the inducing current: the stronger the magnetic field the greater the current
3) Number of loops in the coil: more loops = goated
4) Rate of change on the magnetic field: faster the field changes the greater the current
what is lenz law
when a mf creates a current in a coil and the mf from the new current will oppose the charge that produced it.
(extra) but as the object moves away it attracts it
what is a solenoid
A solenoid is a device comprised of a coil of wire,
and has many uses because it operates like a bar magnet, but it can be switched on and off and is used in things like audiospeakers or electric bells
what is a galvanometer
A galvanometer is an electromechanical measuring instrument for electric current. similar to a ammeter ig
LAW OF ELECTROMAGNETIC INDUCTION and whos law was it
any change in a magnetic field near a conductor induces a voltage in the conductor causing a induced current
Faradays law
what is electromagnetic inductions?
the ability of a magnetic field to create current inside a conductor.
the number of loops in a electric current is ______ to the electric current induced in a conductor
proportional
WHAT IS CURRENT PROPORTIONAL TO?
WHAT IS # OF LOOPS PROPORTIONAL TOO?
PERMEBILITY OF CORE RELATED TO B
MF
MF
THE FACTORE BY WHICH A CORE MATERIAL INCREASES THE B (MF)
Emf
Electromotive force
what does the motor principle state
that a current carrying conductor that cuts across external magnetic field lines experiences a force perpendicular to both the magnetic field and the direction of the electric current
and
there is a mechanical force on any wire when it is conducting electricity while contained within a magnetic field. The force is described by the Lorentz force law and is perpendicular to both the wire and the magnetic field.
what does the split ring communtator do
The purpose of the split ring commutator is to reverse the current every 180o. This ensures that the torque continues in the same direction. The split ring commutator makes connection with the rotor coil (armature).
what do brushes do
- they allow rotation
- transfer electric current to the armature through contact with the split rings
what direction does a compass point when it is near a wire conducting electricity
directly away the wire
what is a benefit of a solenoid over a bar magnet
a solenoids magnetic field can be reversed because we can change the poles surrounding it unlike a bar magmet where the N-pole and S-pole is stationary.
also strength of mf can be increased by increasing loops in coil
