chapter 11 Flashcards
regions where attractive and repulsive properties are concentrated
2.magnetic poles
object capable of attracting iron or steel objects by magnetic force
1.magnets
object or particle with magnetic properties
3.magnetic dipoles
region of influence surrounding a magnet
4.magnetic field
law stating that opposite magnetic poles attract and like magnetic poles repel
5.law of magnetism
phenomenon observed materials that are highly permeable to magnetic lines of force
6.ferromagnetism
exhibited by materials that are only slightly attracted to magnets
7.paramagnetism
microscopic region of a metal where most of the magnetic poles are oriented in a single direction
8.domain
ferromagnetic material containing enough magnetic domains to give it a permanent magnetic character
9.permanent magnet
form of magnetism that results from the net difference of a mixture of opposed magnetic dipole in a natural magnet
10.ferrimagetism
natural tendency of all matter to weaken a magnetic field
11.diamagnetism
temperature above which a permanent magnet loses its ferromagnetic properties
12.Curie temperature
point representing the intersection of the earth’s axis with its surface in the north hemisphere
13.geographic North pole
slowly drifting point on the earth’s surface in the northern hemisphere where the earth’s magnetic field lines are most concentrated and nearly vertical as they pass into the earth’s pole
14.magnetic North Pole
magnetic field of the earth
15.geomagnetic field
Rule stating that the direction of the magnetic field surrounding a current-carrying conductor is indicated by the direction the fingers wrap around the conductor if it is grasped with the right hand, the thumb pointing in the direction of the conventional current flow.
16.right - hand rule of magnetism
An electromagnetic device consisting of a cylinder formed by many wraps of wire. When carrying a current, a strong magnetic field forms within the cylinder of wire. If it contains an iron core, it is a ferromagnetic solenoid, or electromagnet.
17.solenoid
A solenoid with a ferromagnetic core.
18.electromagnet
Electricity generated from a changing magnetic field or a magnetic field generated by an electrical current.
19.electromagnetic induction
Part of an electrical motor or generator that rotates. Depending on the application, it may include permanent magnets or electromagnets.
20.rotor
The stationary part of an electrical motor or generator that contains the magnets or induction coils that surround the rotor
21.stator
An electrical current that periodically changes direction at a specific frequency. In the United States, that frequency is 60 Hz.
22.alternating current
The SI unit of frequency; 1 Hz = 1 cycle/s, sometimes represented by s–1.
23.hertz
Any mechanical device that converts fluid motion into rotary motion as the fluid passes through propeller-like blades.
24.turbine
A device that converts the alternating current inside a DC generator to a DC output or converts a DC supply to an alternating current inside a DC motor. It consists of segments of metal mounted on the rotor shaft and connected to the individual coils mounted on the rotor of the machine.
25.commutator
One of the many curved blocks of conductive material that ride on a rotor commutator to connect the rotor coils to the external electrical circuit
26.brush ( electrical )
A machine that converts electrical energy into rotational mechanical motion.
27.motor
An electrical device used in AC circuits consisting of two coils of wire wound on a single ferromagnetic core, usually shaped like a hollow square. A transformer can either raise or lower the voltage in an AC circuit compared to that supplied by another circuit or isolate one AC circuit from another.
28.transformer
An electromagnet made of a material that has zero resistance to current flow, usually at temperatures very close to absolute zero.
29.superconducting magnet
