Electrostatics Flashcards

9492915997	electrostatics	the science dealing with static electric charge	0
9492924665	charge	a special state of the body in which it is able to take part in electric interactions	1
9492934022	positive charge	the charge of a glass rod rubbed with silk	2
9492936017	negative charge	the charge which is attracted by the positive one	3
9492954555	basic electric phenomena	-attraction -repulsion -influence -charging up -neutralization -grouding	4
9492964534	attraction	unlike charges attract eachother	5
9492966804	repulsion	like charges repell eachother	6
9492968775	influence	positive and negative charges separate inside an originally neutral body as the effect of a charged body	7
9492978103	grounding	when connectin an electrically charged body and the Earth with a conductor the charge flows to the Earth	8
9492987958	neutralization	seperated positive and negative chrages equlize eachother inside a body or a system	9
9492993065	neutral body	the body has no charge OR it has both positive and negative charges of the same quantity	10
9493000080	electric conductor	material in which charge flows freely	11
9493005796	electric insulator	material in which charge does not flow freely	12
9493009667	electrolyte	a substance producing an electrically conducting solution when dissolved in a polar solvent such as water	13
9493024007	electroscope	a device for detecting the presence and determining the sign of electric charges by means of attraction and repulsion	14
9493034676	plazm state	a state of matter in which ions and electrons move freely (electrolized gas)	15
9493040617	source body	a body which generates an electric field	16
9493044707	test body	a body used to investigate an electric field	17
9493049422	electrically closed system	charge can not enter or leave the system	18
9493051878	electric force	a type a force exerted by a charged body on its surroundings	19
9493071108	Coulomb's law	the electric force depends on the 2 charges and the distance between them	20
9493084431	principle of the conservation of electric charge	in an electrically closed system the totl amount of charge is constant in time	21
9493090093	electric field	a special region of space in which electric effects can be observed	22
9493097344	homogeneous electric field	the field lines are parallel and the density of them is constant	23
9493103465	inhomogeneous field	the field lines aren't parallel and their density is not constant (e.g.: radial structure of a pointlike source body)	24
9493109673	electric field strength	it gives the value of the electric force on a unit positively craged test body	25
9493120012	the vector of electric field stregth	a vector which has always the same direction as that of the electric force exerting on a positively charged test body	26
9493128339	electric field lines	imaginery curves indicating the direction of the electric field strengt vectors. at any point of the field line the direction of the electric field vector is always tangential	27
9493142739	properties of electric field lines	-field lines always start from a positively charged source body -field lines always terminate at a negatively charged source body -field lines never intersect eachother	28
9493154115	electric flux	the number of field lines intersecting a unit imaginary surface parallelly (in rality there are infinite number of field linesí)	29
9493169982	linear density of electric charge	the electric charge of a unit length	30
9493173528	surface density of electric charge	the electric charge of a unit surface	31
9493175587	shielding	there is no electric charge inside a conductor	32
9493178972	stable equilibrium position	when removing the body from its equilibrium position it will return after the force exerting on it ceases	33
9493190414	unstable equilibrium position	when removing the body from its equilibrium position it will not return after the force exerting on it ceases	34
9493199192	work done by an electric field	the electric field does work when the test body moves along the field lines; the work only depends on the initial and final position of the object and not the path connecting the two positions	35
9493212347	level	the set of points in the electric field when moving a test body between these points there is no work done by the electric field on the test body	36
9493222876	conservative field	the amount of work done on the test body by the field is independent of the shape of the path	37
9493228357	voltage	voltage gives the work done on a unit positively charged test body by the electric field while carrying it from one level to another	38
9493237668	potential	the needed amount of work to carry a unit positively chraged test body from zero level to a certain point	39
9493247732	potential energy	the amount of energy gained by the test body while carrying it from the zero level to another one	40
9493258403	principle of energy conservation in an electric field	the total amount of energy of a test body in an electric field is constant in time	41
9493272578	conductors in an electric field	-the charges accumulate on the surface of the conductor as a result of the repulsion of like charges -field lines started from a conductor behaving as a source body are perpendicular to the surface -all the points of the surface of a conductor have the same potential->they form a level -when placing a conductor in an electric field a new electric field is generated in which the field lines are the opposite of the original ones. Because of this the resultant electric force inside a conductor is always 0, so no electric effects can be experienced inside the conductor. This is the phenomenom of shielding	42
9493318094	pinpoint effect	electric charge is accumulated on the surface of a metalic conductor at positions of biggest curvature	43
9493326648	electric wind	the wind blowing from a source body as a result of repulsoin of like charges	44
9493336518	electric capacitance	capacitance gives the needed amount of charge to generate a unit potential difference	45
9493366473	condensor	a special type of electric instrument consisting of two pieces of oppositely charged metal which can store a large amount of charge on the surface	46
9493377096	polarization	in an insulator bc of the rotation of the dipole molecules the resultant electric field stregth decreases when putting it between two condensor plates	47
9493401718	series combination of condensors	-all the charges are equal -the total amount of voltage is equal to the sum of the voltages -there is inverse propotion between the voltages dropping between the two plates of the condensors and the capacitances -the reciprocal of the equivalent capacinótance is equal to the sum of the reciprocals of the capacitances of the original condensors	48
9493473125	equivalent capacitance	the capacitance of the imaginery condensor substituting the original ones so that it has the same effects as them	49
9493481750	main branch	from the positive pole to the first junction and from the last junction to the negative pole	50
9493489752	junction	where the brances meet	51
9493492177	parallel combination of condensors	- the total amount of charge is equal to the sum of the charges -all the voltages are equal -there is direct propotion between the charges and the capacitances -the equivalent capacitance is the sum of the capacitance of the original condensors	52
9493518421	electric energy	the amount of energy stored inside the electric field of the condensor	53
9493524165	electric current	the ordered flow of electric charge	54
9493528904	direct current	charge flows to the same direction	55
9493533689	alternating current	there is periodic change in the direction of the flow of the charge	56
9493539972	current intensity	the amount of charge flowing through a certain crossection of the wire in a unit time	57
9493548038	superconductors	special type of metals or coils of metals in which when starting an electric current the current intensity will be constant without applying an electric source	58
9493557860	heat effect of electric current	it is a direct and compulsory effect e.g.: oven, hairdryer, electric heat radiator...	59
9493569446	magnetic effect of electric current	it is a direct and compulsory effect e.g.: electromagnet (coil of wire+iron core; current->magnetization->good bc its strength can be easily changed)	60
9493576824	chemical effect of electric current	direct effect of direct current but not alternating current	61
9493595155	electrolysis	any type of process during which chemical reactions are started as the effect of the electric current driven into certain materials	62
9493618945	electrode	a piece of metal submerged into an electrolyte	63
9493623900	indifferent electrode	an electrode made of stable materilas so that it carries the current inside the water solution but it doesn't take part in chemical reactions	64
9494713863	biological effect of electric current	it is a consequence of the other effects (heat nad chemical): muscles contract, burn- the human body acts as a watersolution	65
9494724950	light effect of electric current	it is a consequence of the other effects	66
9494731613	conditions of the flow of the electric current between two points	-there is potential difference between the points -the points are connected with a conductor	67
9494739636	technical direction of current	by definition current cosists of positive charges	68
9494745732	real direction of current	in reality electrons (negative charges) flow	69
9494752867	electric source	an instrument carrying electric charge from the position of lower potential to the position of higher potential (work is done)	70
9494761785	types of electric sources	-galvanic cell -generator -solar cell	71
9494764016	galvanic cell	electric source producing electricity with the help of chemical reactions	72
9494769974	redoxi reaction	electron transport from a certain material to another	73
9494773641	generator	an instrument producing electricity with the help of electromagnetic induction (e.g.:dynamo)	74
9494780126	motional induction	current is induced inside a coil of wire surrounding a rotating magnet	75
9494789067	solar cell	an instrument made of semiconducting materials in which electron transportation is generated when exposed to light	76
9494794293	diod	any type of instrument which regulates the direction of the current	77
9494799304	consumer	any type of instrument which uses the energy of the current	78
9494803288	electric resistor	any type of instrument on which the current has heat effect	79
9494808526	electric resistance	it gives the value of the needed voltage generating unit current intensity between two points	80
9494815383	resistance depends on	-length of wire -cross section of wire -material of the wire -temperature of the wire	81
9494830377	series combination of resistors	-the current intensities are the same everywhere -the total amount of voltage is equal to the sum of the voltages of the original resistors -the equivalent resistance is equal to the sum of the original resistances -there is direct propotion between the voltages dropping on the resistors and the resistance values -advantage: many resistors of small resistance values have enough resistance together to work -disadvantage: if one of the resistors goes wrong none of them work -e.g.: christmas lights	82
9494849549	equivalent resistor	an imaginery resistor substituting the original ones so that it has the same effect as that of the original ones	83
9494886540	parallel combination of resistors	-the total current intensity is equal to the sum of the current intensities flowing through the original resistors -the voltage dropping on the resistors are equal everywhere -the reciprocal of the equivalent resistance is equal to the sum of the reciprocals of the resistances of the original resistors -there is inverse propotion between the current intensities and the resistance values -advantage: independent use -disadvantage: too many consumers can not work together -e.g.: electrical multi-outlet	84
9494922329	Wheatstone-bridge	a type of bridge combination in which the ratio of the resistances in the two brances are equal	85
9494929998	Kirchoff's first law	the algebraic sum of current intensities flowing towards or away from a junction is equal to 0	86
9494937356	Kirchoff's second law	the algebraic sum of the voltages dropping on the single resistors or generated by the sources is equal to 0 for a full cycle/loop in the circuit	87
9494947695	power of electric current	the amount of heat developed in unit time	88
9494952263	short circuit	two points in a circuit are connected with a wire of 0 resistance	89
9494956288	potentiometer	any type of instrument whose resistance can be changed easily	90
9494961056	internal resistance	the resistance inside the source which is always present	91
9494965331	internal voltage	the voltage dropping on the source itself	92
9494968251	full circuit	always contains the internal resistance of the source	93
9494972428	electromotoric force	the maximum voltage which can be generated by the source	94
9494978101	the special case of opened circuit	-the external resistance is infinite -the current intensity is 0 -the internal voltage is 0 -the electromotoric force is equal to the external voltage	95
9494991545	the special case of short circuit	-the external resistance is 0 -the equivalent resistance is equal to the internal resistance -maximum current intensity	96
9494998536	ammeter	an instrument measuring current intensity; it is always combined serially to get proper results	97
9495005046	ideal ammeter	its resistance is almost 0	98
9495007511	measurement limit	maximum current intensity/voltage which can be observed without the instrument going wrong	99
9495015482	shunt	a resistor combined parallelly with the ammeter to extend its measurement limit	100
9495021790	voltmeter	a type of instrument measuring voltage ; it is always combined parallelly to get the proper results; another serially combined resistor is neede to extend its measurement limit	101
9495033850	ideal voltmeter	its resistance is close to infinite	102