Electromagnetism And Electrodynamics Flashcards
How do you apply the right hand wire rule?
Physically do it: thumb pointing in the direction of conventional current and your fingers curling in the direction of the magnetic field around the wire.
Superposition principle (applied to a loop)?
The net magnetic field at any point inside the loop is the sum of the individual magnetic fields caused by all the individual parts of the loop.
Solenoid?
A series of turns wound next to each other. On the outside, the field represents that of a bar magnet and inside, the field lines are all parallel.
Electromagnets?
Magnetic material that has wire around it for the purpose of their magnetism being switched on and off as needed. They can be much stronger magnets.
List at least three types of electromagnets.
Electric motors, loudspeakers, telephones, relay switches, microphones, lifting device of cranes, bells and CAT - scans.
Electromagnetic Induction?
Occurs when a solenoid and a magnet move relative to each other, inducing a current. The presence of the current means the solenoid is a voltage source.
Magnetic Flux Linkage? What are its two acceptable S.I. units?
The product of the number of turns on the coil and the flux through the coil. T.m² and Wb.
Magnetic Flux Density?
A representation of the magnitude and direction of the magnetic field.
Faraday’s Law of Electromagnetic Induction?
The emf induced is directly proportional to the rate of change of magnetic flux.
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.
Generator?
An electrical machine that converts mechanical energy into electrical energy by changing the magnetic flux through a coil.
What are the parts of a AC generator?
The coil, the magnet, the slip rings, the carbon brushes, the terminals and the rotating mechanism.
What are the parts of a DC generator?
The coil, the magnet, the split ring commutator, the carbon brushes, the terminals and the rotating mechanism.
What do your 3 fingers represent when utilizing the right hand generator rule?
Thumb: Motion.
First finger: Magnetic field (North to South).
Second finger: Current direction.
How can the emf and current be increased?
By increasing the number of turns in the coil (N). By using a stronger magnet (increasing B). By increasing the area (A) enclosed by the coil. Lastly, by turning the generator coil faster.
