| A | B |
|---|
| heat | not a method of magnetization |
| ferromagnetic | material that is strongly attracted to magnets and that has several unpaired electrons per atom |
| paramagnetic | a material that is weakly attracted to magnets and that has only one unpaired electron per atom |
| magnetic equator | an imaginary circle around the earth halfway between teh two magnetic poles |
| kilowatt-hour | unit used by electric companies to charge for electricity |
| ohm | unit used for measuring resistance |
| watt | SI unit of power |
| ampere | unit of electron current |
| volt | unit is used to measure the force with which an electric current flows |
| coulomb | unit of electric charge |
| superconductor | material that allows electric surrent to flow through it with no resistance |
| open circuit | a circuit that contains a gap which electrons cannot cross |
| series circuit | a circuit with loads arranged so that the electric current flows through each load one after the other |
| closed circuit | a circuit that contains a complete path for electrons to flow from the source of current, through the load, and back to the source |
| parallel circuit | a circuit with loads arranged in separate branches of the circuit so that the current is divided among them |
| capacitor | a modern device used to store electrical charges, such as in some camera flashes and other electronc deivces |
| fluorescent lamp | an electric discharge lamp which produces light by passing an electric current through a long tube filled with mercury vapor at low pressure, causing a coating on the inside of the tube to glow |
| electrostatics | study of the nature, behavior, and uses of static electricity and related phenomena |
| negative | electron |
| electric field | region surrounding a charged object in which other objects are attracted or repelled by an electric force |
| grounding | process of diverting unwanted electrical charge directly into the earth |
| induction | electric charge can be imparted at a distance, without direct contact between the charged object and the uncharged object |
| outside | electric charge always moves to the __ of the charged object |
| battery | a group of electrochemical cells connected together as a single source of current |
| lodestone | Vikings were guided in their journeys across the North Atlantic by unusual magnetic rocks |
| S-pole | the north magnetic pole of the earth is magnetically an___ |
| Van Allen | twovast, doughnut-shaped belts of high-speed particles trapped in the earth's magnetic field ___ radiation belts |
| neutral | atom with no overal electrical charge |
| conductors | materials through which current flows easily |
| semiconductors | materials that are neither good conductors nor good insulators |
| resistance | the amount a certain object or material hinders electron flow |
| storage cells | devices that produce electric current and are designed to be recharged when they run dry |
| circuit breaker | automatic switch that opens the circuit when current flowing through it exceeds a predetermined amount |
| dipping needle | compass that swings vertically to reveal the angle at chich lines of force enter the earth |
| telegraph | device for communicating over long distances by means of electromagnets |
| lightning rod | device for protecting buildings and other structures from lightning strikes |
| electric motor | device that converts electricity into motion |
| loudspeaker | device that converts pulses of electricity into sound waves |
| transformer | device that increases or decreases the voltage of alternating current by emans of electromagnetic induction |
| electromagnet | device that produces a strong magnetic field when electricity passes through it |
| Van de Graff generator | device used to produce static electricity |
| generator | device that uses electromagnetic induction to produce electric current |
| switch | device used to manually open or close a circuit |
| Leyden jar | early device used to store an electric charge |
| ammeter | instrument used to measure amperage |
| magnetic compass | navigational device consisting of a magnet free to swing horizontally |
| magnet | object capable of attracting objects such as iron or steel |
| electroscope | simple device that uses the laws of electrostatics to detect small electric charges |
| Ohm's law | current(amperage) in a conductor is directly proportional to voltage and inversely proportional to resistance |
| law of electric charges | opposite charges attract, but like charges repel |
| law of magnetic force | the force between two magnetic poles is directly related to the product of the pole strengths and inversely related to the square of the distance between the poles |
| law of magnetic poles | unlike poles attract, but liek poles repel |
| domain theory | the magnetic field of a magnet is the sum of thousands of smaller fields, each produced by billions of atoms containign unpaired, spinning electrons |
