Electrodynamics Flashcards
Faraday’s law:
The emf induced is directly proportional to the rate of change of magnetic flux (flux linkage).
AC
Alternating current. Current which reverses direction periodically.
Commutator:
A device which ensures that the direction of the current in a coil is reversed every half revolution.
Conventional current:
The rate of flow of positive charge from the positive terminal of the cell to the negative terminal.
DC
Direct current. Current flowing in one direction only.
Electromagnetic induction:
Occurs when a current is induced in a closed conducting loop when
there is a change in the magnetic flux passing through the surface
area of the conducting loop.
Induced emf:
The total amount of electrical energy supplied per unit positive charge.
Magnetic fields:
Produced by magnets or by moving electrical charges. Magnetic field lines
are drawn to represent the direction of the magnetic field at a point. The
symbol for magnetic field is B and its unit is the Tesla (T).
Magnetic flux density:
A representation of the magnitude and direction of the magnetic field.
Magnetic flux:
For a loop of area (A) in the presence of a uniform magnetic flux density (B), the
magnetic flux (Ф) passing through the loop is defined as Ф = BA cosθ, where θ is the
angle between the magnetic flux density (B) and the normal to the loop of the
area (A).
Magnetic flux linkage:
The product of the number of turns on a coil and the flux through a coil (NФ).
Lenz’s law:
The induced current flows in a direction so as to set up a magnetic field to oppose the change in magnetic flux.
Diode:
A component that only allows current to flow in one direction.
Generator:
A device which converts mechanical energy into electrical energy.
Motor:
A device which converts electrical energy into mechanical energy.
