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science Ch. 15-16
science 9th grade
answers | questons |
---|---|
open circuit | a circuit that containsa gap which electrons cannot cross |
electrosc | simple device that uses the laws of electrostatics to detet small electric charges |
domain theory | the magnetic field of a magnet is the sum of thousands of smaller fields, each produced by billions of atoms containing unpaired, spinning electrons |
law of magnetic poles | unlike poles attract, but like poles repel |
switch | device used to anally open or close a circuit |
transformer | device tht increases or decreases the voltage or alternating current by means of electromagnetic induction |
speaker | device that converts pulses of electricity into sound waves |
paramagnetic | a material that is weakly attacted to magnets and that has only one unpaired electron per atom |
amere | the unit of elecn current |
semi conductors | materials that are neither good conductors nor good insulators |
dipping needle | compass that swings vertically to reveal the angle at which lines of force enter the earth |
equator | an imaginary circle around the earth halfway between the two magnetic poles |
genorator | device that uses electromagnetic induction to produce electric current |
electro statics | the study of the nature, behavior, and uses of static electricity and relate phenomena |
Van Alen Belt | the two vast, doughnut-shaped belts of high-speeds particles trapped in the earth's magnetic field |
kilawatt hour | the unit used by electric companies to charge for electricity |
Leyden Jar | early device used to store an electric charge |
curcuit breaker | automatic switch that opens the circuit when current flowing through it exeeds a predetermined amount |
magnet | object capable of attracting objects such as iron or steel |
electric motor | device that converts electricity into motion |
nuetral | an atom or other object that has no overall electrical charge |
telagraph | device for communicating over long distances by means of elecroagnets |
grounding | the pocess of diverting unwanted electrical chage drectlyinto the earth |
condctors | materials through which current flows easlily |
coulomb | the unit of electical charge |
series | a circuit with loads arranged so that the electric current flows through each load one after another |
Ohms Law | current (amerage) in a conductor is directly proportional to the voltage and inversely proportional to resisance |
north magnetic pole | it is magnetically an s-pole |
parrallel | a circuit with loads arranged in separte branches of the cirguit so that the current is divided among them |
electromagne | device that produces a strong magneti field when electricity passes throug it |
Vande Graph | device used to produce static electricity |
watt | the SI unit of power |
storage cell | devices that produce electric current and are designed to be recharged when the "run dry' |
ampmeter | instrument used to measure amerage |
electric field | the region surrounding a charged object in which other objects are attracted or repelled by an electric foce |
resistance | the amound a certain object or material hinders electron flow |
battery | a group of electrochemical cells connected together as a single source of current |
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 |
electron | possesses a negative charge |
ohm | the unit used for measureing resistance |
electric charge | always moves to the outside of the charged object |
faramagnetic | a material t is strongly attracted to magnets and that has several unpaired electrons per atom |
capasitator | a modern device used to store electrical charges such as in some camera flashes and other elctronic devices |
magnetic compass | navgational device consisting of a magnet free to swing horizontally |
lightning rod | device for protecting buildings and other structures from lightning strikes |
closed curcuit | a circuit that contains a complete pathe for electrons to flow from the source of current through the load, and back to the source |
volt | the unit used to measure the force with which an electric current flows |
induction | electric charge can be imparted at a distance without direct contact between the charged object and the uncharged object |
ball of electric charges | opposite charges attract, but like charges repel |
loadstone | the Vikings were guided in their journeys across the North Atlantic by these unusual magnetic rocks |
furesent lamp | an electric discharge lamp which produces light by passng and electric current through long tube filled ith mercury vapor at low pressure, causing coating on the inside of the tube glow |
super conductors | a matrial that allows electric current to flow through it with no resistance at all |
contact, electricity, induction | magnetization methods |
in current electricity, the electrons "flow" from one place to anoter n static electricity, the electrons reain in one place. Tey are stationary | how does current electricity differ from static electicity? |
the angle of declination | whatis the angle that a compass needle deviates from the true north called? |
when an object is electricly charged, its electrons tend to "sty put" on the surgac of the charged object. Static means Stationary | why are electic charges commonly called static electricity? |
a stream of protons and electrons tat emanates from the sun | what is solar wind? |
direct current (DC) alternating current (AC) | what are the two types of electric current |
source of current, cnductors, load | lis the three main components of a simple electric ciruit |
when electricity is given the opportunity to take a "short cut" through a circuit, avoiding the load | when does a short circuit occor? |
Both mgnetism and electricity are manifestations of the electromagnetic force/ when an electic current flows through a wire, it generates a magnetic field around the wire, forming an electromagnet. | Explain the close relationship betwen magnetism and electricity. |
When a conductor "cuts" the lines of force in a magnetic field, it generates an electric current | how can electricity produce magnetism, and magnetism produce electricity? |