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Connie Unit dos
Electrical stuff
| Question | Answer |
|---|---|
| What is the phenomena associated w/ stationary and moving positive and negative charges? | Electricity |
| Two types of electricity: | 1. current electricity2. static electricity |
| Electricity in motion (dynamic charges) | current electricity |
| Electricity at rest (stationary charges) | Static electricity |
| What is the study of stationary electric charges? | Electrostatics |
| The unit used to measure a static charge is called the ? | Coloumb (C) named after Charles Coloumb. |
| The Coloumb (C) is a fixed (constant) number of positive or negative charges and is equal to ? | 1 C = 6.3 x 10^18 charges |
| the process of applying a positive or negative charge to a neutral object through the transfer of electrons. | Electrification |
| To make a neutral object become negative, are electrons added or removed from the object? | Added |
| To make a neutral object positive, are electrons added or removed from the object? | Removed |
| Surrounding every charged object is an ? | Electrostatic field |
| The electrostatic field has ?? as the charge on the object producing the field. | The same |
| What determines the area of the field? | The intensity (quantity) of the charge. |
| What will produce a large field, a small or big charge? | The greater the charge, the bigger the field. |
| The planet Earth is considered to be an infinite ? for electrons. | Resorvoir |
| An object is said to be grounded when it is ? connected to the ground using a material that will permit e- to easily move between the earth and the object | Physically |
| What is the primary goal for grounding throughout any facility? | Safety |
| What is the secondary goal for grounding? | Effective Lightning Protection |
| An object that is said to be positive has a ? of electrons. | Deficiency |
| What is the path flow of electrons if a positive object is electricall grounded to the earth? | Electrons will move FROM the earth into the positive object until it is neutralized. |
| An object that is negative has too few or too many electrons? | It is said to have too many.(an excess of e-) |
| What is the path flow of electrons if a negative egative object is electrically grounded to the earth? | Electrons will move from the negative object into the Earth until the object is neutralized. |
| Electrically connecting any charged object to the Earth(grounding) will ?? the object. | Instantly neutralize |
| Electrical symbol for ground | ( arrow pointing down) |
| Electrostatic Law #1 | Like charges repelunlike charges attract |
| Electrostatic law #2 states that electric charges reside where on a a charged object? | On the external surface |
| The force between two charges is ? ? to the product of their magnitudes and ?? to the square of the distance between them. | directly proportional/inversely proportional |
| Alternating current describes current that continuously ? direction as it moves through a substance. | changes |
| Direct current describes a current that moves through a substance in the ? direction. | Same |
| Which charges can move through all states of matter? (solids, gases, and liquids? | Negative |
| Which charges can only move through liquids, and gases? | Positive charges |
| As current electricity moves through matter, charges enounter ? w/ each other and atoms of matter itself. | Friction |
| Friction is also known as | Resistance |
| Electrical charges will always follow the path of ? resistance | Least |
| Any substance which permits electrical charges to move very easily through that substance. (very low resistance) | Conductor |
| gold, silver, copper, aluminum are examples of... | Conductors |
| Any substance that blocks the flow of charges through the substance. (very high resistance) describes: | Insulator |
| glass, rubber, plastic, wood are examples of: | Insulators |
| Substances that act as conductors under certain conditions and as an insulator under other conditions describes: | Semiconductors |
| germanium, silicon are known as: | semiconductors |
| Superconductors are substances that have blank resistance when operated at extremely low temp. | Superconductors |
| Nobium and Titanium are known as: | superconductors |
| Electricity that moves from positive to negative describes: | Concept of conventional flow |
| Electricity that moves from electric to positive describes: | Concept of electron flow |
| Electrician follow which concept of flow? | Conventional flow |
| Radiographers follow which concept of flow? | Electron flow |
| When one electron is inserted into one end of the conductor... | the electrons move forward until one electron is ejected on the other end. |
| The source for external electrons is... | Power Supply |
| the electron that is displaced from the conductor carries what type of energy? | Kinetic |
| What causes the electrons to move in the conductor? | A difference in poetential energy must exist between two locations to make current. |
| The force created between two locations (Potential energy difference) in the conductor is called the: | Electromotive force |
| Potential energy difference, electromotive force and ? are all synonymous. | Voltage |
| EMF causes the electrons to move from the area of ? concentration toward the area of ? concentration. | Higher to lower. (more negative to less negative) |
| The movement will continue until a ? is established throughout the substance. | Equilibrium of charge concentration |
| Unit of electromotive force is called the: | Volt |
| The number of electrons passing a given point per unit of time is a measure called: | Current Intensity |
| Current Intensity is called the: | Ampere |
| One ampere equals: | One coulomb of charge moving past a point per second. 6.3x10^18 charges |
| The inherent action which opposes the forward movement of current describes: | Resistance |
| The unit of electrical resistance is: | Ohm |
| Resistance due to the characteristic electrical conductor material itself: | Inherent resistance |
| Factors affecting inherent resistance | Length of conductor, Cross sectional area of the conductor, What the conductor is made of, Temp of conductor during current movement. |
| What is the relationship of the length of the conductor to its inherent resistance | Directly proportional (the longer the conductor, the more resistance) |
| What is the relationshiip of the cross sectional area to its' inherent resistance | They're inversely proportional (The bigger the cross sectional area, the less the resistance) |
| Elements with what type of valence and how many shells will have a lower resistance? | A valence of +1 and more shells Gold vs. silver vs. Copper |
| As the temperature increases the inherent resistance: | Increases |
| what is a fixed resistance? | Resistor |
| What is a variable resistance? | Rheostat |
| Resistor symbol | Fixed amount of resistance |
| Rheostat symbol | Variable amount of resistance |
| Added resistance in a conductor is called a ? | Load |
| The purpose for any electric circuit is ? | To create power to do work |
| Electric power is the product of ? | Current Intensity and electromotive force |
| The formula of power= | P = I x V |
| Unit of measurement for electric power is: | Watt |
| Electric circuit is a closed complete ? pathway through whhich current can move. | conductive |
| Minimum circuit requirements: | Closed conductive pathpower supplyloadon-off switch |
| What are the four types of circuits: | series, parallel, complex, short |
| Which three are functioning ciruits? | Series, parallel, complex |
| A series circuit provides only ? pathway to follow and where ? is constant at all locations throughout the circuit. | Pathway, amperage |
| Parallel Circuit provides more than one pathway for current to follow and where ? is constant across all pathways. | Voltage |
| If a circuit contains some loads that are in a series and others that are in a parallel the circuit is called ? | A complex circuit |
| If the total electrons that move through one load are the same amount of electrons that move through another load than the two loads are said to be | In series |
| If the total e- move through one load are not the same e- that move through another load than the two loads are said to be in | Parallel |
| A short circuit that contains ??? causes excessive heat to build within the circuit. | Insufficient added resistance |
| What has to be properly balanced for the circuit to operate correctly and safely? | Current Intensity (amp),electromotive force (volt), and resistance (ohm). |
| The balance is determined by what law? | Ohms law |
| Ohm's law states: | Current intensity is directly proportional to electromotive force and inversely proportional to resistance |
| what are the variations of ohms law? | I=V/R V=IR R=V/I |
| Ohm's law sates the relationship between? | Current and voltage and resistance |
| Watt's law states the relationships of: | Power, and current and voltage and resistance. |
| Watts formula: | P=IV I=P/V V=P/I (pivvir) |
| What are the four effects of electric current? | Luminous effect thermal effectMagnetic effect Chemical |
| which effects always occur? | Magnetic and thermal effect. |
| When a current is passed through a resistance, friction occurs that produces heat | Thermal effect |
| Power loss (heat production) formula | P=I^2R |
| Chemical Effect: | Placing certain chemicals b/n two electrical points (electrodes) will cause a reaction producing emf and current flow |
| Types of batteries: | Dry cell and Wet cell |
| Dry cell battery has a moist chemical paste b/n two electrodes which creates chem. reaction and producing and emf of how many volts per cell? | 1.5 volts |
| Wet cell battery has a liquid between two electrodes creates chem reaction to produce an emf of how many volts per cell? | 2.0 volts |
| Devices used to measure electrical current characteristics: | Ciruit meters |
| Anmeter measures | amperage |
| Voltmeter | voltage |
| Battery symbol | 1 cell 2 cells 4 cells |
| The ability of certain materials to attract iron: | Magntism |
| Any material that can attract a piece of ? describes a magnet. | Iron |
| Process whereby a certain material becomes a magnet | Magnetization |
| How many years ago when the magnetic phenomena was first observed? | 3000 years ago |
| where was it first discovered? | Present day Turkey (then called Magnesia) |
| The ore that was discovered was named | Magnetite |
| Magnetite is now called: | Lodestone |
| What was the first true scientific device on record that operated under the principles of magnetism? | Compass |
| The compass was created during what time? | 1000 A.D |
| Who discovered that a magnet has polarity (Poles)North and south | Peter Peregrinus |
| Who discovered that the planet Earth is one giant magnet during the 16h century? | William Gilbert |
| Who discovered that an electric current will produce a magnetic effect in 1820? | Hans Oersted |
| Who discovered that a magnetic effect can ve used to produce an electric current in 1835? | Michael Faraday |
| What are the three types of magnets? | Natural, artificial, and electromagnets |
| Natural magnet is any material that naturally exhibits the property of magnetism (not manmade) whate are the two examples? | Lodestone and Earth |
| Artificial magnet is a manmade material that exhibits the property of magnetism. What is an example? | Alnico, a strong magnet made of aluminum, nickel, and cobalt. |
| Electromagnet is a material that exhibits the property of magnetism only during the application of what? | an electric current |
| What is a conductor wire shaped into a coil? | Helix |
| When the helix is connected into a circuit so electricity moves through the coil a ? is formed? | Solenoid |
| A solenoid is also known as an? | Inductor |
| When a rod of iron is placed through the center of the coil of the solenoid what is formed? | Electromagnet |
| Magnetism law #1 states that regardless of shape/size every magnet has two poles: | North pOle and south pole |
| Magnetism law#2 states that: | Like magnetic poles repel each other, unlike magnetic poles attract each other |
| Magnetism law #3 states that the force of attraction/repulsion between two magnetic poles are directly proportional | to the product of the strengths of the poles and inversely proportional to the square of the distance between the poles |
| Third magnetic law is sometimes called the: | Law of Gauss |
| Surrounding every magnetic is a field magnetic energy composed of lines of force called | maagnetic flux |
| the first flux property states that flux exits the | North pole and enters the south pole |
| If some flux travel too far from the magnet w/ insufficient energy to return to the magnet it results in a loss of magnetism | Flux leakage |
| the 2nd flux property states that flux form closed loops "magnetic circuits" and the flux lines from the same magnet never? | cross over each other |
| Flux property 3 states that flux that travel in the same direction... | Repel each other and flux that travel in opposite directions attract each other |
| flux propety 4 states: | flux can be distorted by inserting a magnetic material into the flux field. |
| Whenever a magnetic material moves into the field of a magnet material becomes magnetized while remaining in the field is | magnetic induction |
| Weber's observation #1 | if a mag is broken into 2 pieces each piece becomes a magnet |
| Weber's ob 2 | If a piece of iron is hammered while lying near a magnet will become a magnet |
| Weber's ob 3 | if a piece of iron is heated while near a mag it will become a magnet |
| Weber ob 4 | If a piece of iron is rubbed w/ a mag repeatedly in the same direction it will become a mag |
| Web ob 5 | gently shaking a test tube of iron fillings while near a magnet will turn the fillings into a magnet |
| magnetic domain theory 1 | all magnetic materials are composed of atomic sized magnetics called dipoles |
| dipoles are the smallest unit of matter containing properties of a... | magnet |
| A dipole is a complete magnet w/ a north and south pole with a ? surrounding it? | Magnetic field |
| MDT 2 a magnet is formed when all dipoles are: | arranged in an orderly manner |
| the more dipoles that are arranged in the same direction: | the stronger the magnet |
| Dipoles with no orderly arrangement are not: | magnetized |
| When the dipoles are arranged in an orderly manner what is acquired? | Polarity |
| a type of dipole | an ion in motion |
| Two movements of an orbital electron: | 1. e- moves around nucleus in an orbital path2. e- spins on it's own axis as it moves toward the nucleus (orbital and axial spin) |
| a magnetic moment is formed when what is established around a moving ion? | Magnetic field |
| each type of movement creates an idividual magnetic movement: | Orbital magnetic momentSpin magnetic moment (axial) |
| Another dipole is: | A proton spinning on it's own axis within a hydrogen nucleus. |
| As a proton spins on it's own axis what is formed? | a nuclear dipole |
| Why are some elements magnetic while most are not magnetic? | Based on the spin structure of the atom within a given element resulting in magnetic moments |
| What determines the magnetic properties? | The number of electrons found in the valence shell of the atom |
| when the majority of valence e- travel in the same direction around the nucleus and spin in the same direction on their own axes | The greater is the magnetic potential for that atom |
| Atoms with a what valence electron number have more potential to become magnetic than those with a ? number of valence e-. | Odd/even |
| Atoms with even valence number will demonstrate what kind of magnetic properties? | Pretty much none since the spin motions cancel each other |
| Atoms with a 7 valence e- with seven orbiting clockwise and 0 cc | will display strong magnetic properties |
| But atoms with 7 e- with four orbiting clock and 3 orbiting cc will | demonstrate some magnetic properties but weak |
| Magnets of same substance can demonstrate varying degrees of | magnetic strength |
| Magnetic strength depends on: | Flux intensity andFlux density |
| Flux intensity is the ?? of flux in the magnetic field at a given point in time | total number |
| the greater the flux intensity | The stronger the magnet |
| Unit of flux intensity: | Weber (Wb) 1 Wb=10^8 flux lines (100,000,000) |
| Flux Density: The # of flux per unit of area of magnetic field. | the greater the flux density the stronger is the magnet |
| Unit of flux density: | Tesla (T) IT=1 Wb/m^2 |
| A smaller unit of flux density is called the | Gauss |
| 1T=10,000 G | 1G =1/10000 T |
| e.g. of flux density | Planet earth: 1.0 GRefrigerator magnet= 1000 GMRI magnet 40,000 Gauss |
| All elements can be classified according to the way they interact with an | external magnetic field |
| what are the four magnetic classification of matter? | Ferromagnetic DiamagneticParamagnetic Dimagnetic |
| Ferromagnetic Material is any material that is ? attracted to a magnet | Strongly |
| examples of ferromagnetic material are | iron, cobalt, nickel |
| Paramagnetic material is any material that is ? attracted to a magnet? | Gadolinium |
| Diamagnetic Material is any element which is ? repelled by a magnet | weakly |
| examples of diamagnetic material are: | Beryllium, bismuth, and lead |
| Dimagnetic material (non-magnetic is any element which is not affected in any way by a magnet) examples are: | Plastic, wood, glass |
| Permability also known as: | Susceptability |
| Permability: | The easew/ which a substance can be magnetized |
| Retentivity: | The ability of a magnet to retains it's magnetism. |
| Substances which are high in permeability are ? in retentivity | low |
| examples of high permeability: | soft iron |
| Substances which are low in permeability are ? in rentivity. | high |
| examples of low permeability substances are: | Hard steel |
| Formula for length of conductor and inherent resistance: | L1/L2= R1/R2 |
| The formula for cross sectional area and inherent resistance: | A1/A2=R2/R1 |
Created by:
Roentgen
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