electricity fundamentals

7/27/2019 Electricity Fundamentals

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Electricity Fundamentals

1. What composes all matter whether aliquid, solid, or gas? Atoms

2. Which of the following is not abasic part of an atom? Coulomb

3. What is the smallest element of amatter?Atom

4. To determine whether a material cansupport the flow of electricity ornot, we need to examine its atomicstructure.

5. Approximate diameter of an atom. 10-10 m

6. The lightest kind of atom orelement. Hydrogen7. Known as the simplest type of atom.

Hydrogen

8. Approximate diameter of a Hydrogenatom. 1.1 x 10-10 m

9. A commonly used model in predictingthe atomic structure of a material.Bohr model

10.Is at the center of an atomicstructure in a Bohr model.Nucleus

11.The nucleus of an atom is normallyneutral

12.What particles that revolve aroundthe positive nucleus? Electrons

13. In electricity, positive electriccharge refers toprotons.

14.What is the charge of an electron?1.6022 x 10

-19C

15.The mass of a proton isapproximately 1.6726 x 10-27 Kg

16.Protons are about 1,800 timesheavier than electrons.

17. Approximately, how many electronsthat could equal to the mass of asingle proton or neutron? 1,836electrons

18.The maximum number of electrons (Ne)that can occupy a given shell (n) isdetermined by the formulaNe = 2n

2

19.The discrete amount of energyrequired to move an electron from a

lower shell to a higher shell.A. negative energyB. positive energyC. quantumD. quanta

20.Maximum number of orbiting electronsat the first or K shellA. 2B. 4C. 6D. 8

21.Electron is derived from the Greekname electron which meansA. hugeB. tinyC. particleD. amber

22.Electric charge of neutron is thesame asA. protonB. electronC. currentD. atom

23.In an atomic structure, whatparticle that has no charge and

therefore has no effect on itsatomic chargeA. electronsB. protonsC. neutronsD. nucleons

24.The atomic number of an element isdetermined by the number ofA. ElectronsB. valence electronsC. protonsD. protons or neutrons

25.The atomic weight of an element isdetermined by the number ofA. electronsB. valence electronsC. protonsD. protons and neutrons

26.If an element has an atomic numberof 12, there are how many protonsand electrons?A. 6 protons and 12 electronsB. 12 protons and 6 electronsC. 12 protons and 12 electronsD. 12 protons and 24 electrons

27.Suppose there is an atom containingeight protons and eight neutrons in

the nucleus, and two neutron areadded to the nucleus, the resultingatomic weight is aboutA.8B.10C.16D.18

28.It is composed of a series of energylevels containing the valenceelectrons.A.conduction bandB.forbidden bandC.

side bandD.valence band


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29.Electrons at the conduction band are

calledA.free electronsB.valence electronsC.deep state electronsD.shallow state electrons

30._____________ are electrons at theouter shellA. Inside shell electronsB. Conductor electronsC. Outside shell electronsD. Valence electrons

31.Electrons at the outermost shell arecalledA. free electronsB. valence electronsC. deep state electronsD. shallow state electrons

32.Which material has more freeelectrons?A. ConductorB. insulatorsC. micaD. dielectric

33.Which material has the least numberof valence electrons?A. conductorB. semiconductorC. insulatorD. semi-insulator

34.What elements possess four valenceelectrons?A. InsulatorsB. Semi-insulatorsC. SemiconductorsD. Conductors

35.A good conductor has how manyvalence electrons?A. 1B. 2C. 4D. 8

36.Materials that might have eightvalence electrons

A. conductorB. insulatorC. semiconductorD. semi-insulator

37.An insulating element or materialhas capability of _________.A. conducting large currentB. storing voltageC. storing high currentD. preventing short circuit between

two conducting wires

38.A law of nature makes certainmaterials tend to form combinationsthat will make them stable. How manyelectrons in the valence orbit areneeded to give stability?A. 1B. 2C. 4D. 8

39.Determine which statement is true?A. The current carriers inconductors are protons.

B. The current carriers inconductors are valenceelectrons.

C. Valence and inner electrons arethe carriers in conductors.

D. Valence electrons are not theones that become free electrons.

40.A material that contains anabundance of free carrier is calledA. insulatorB. semi-insulatorC. conductorD. semiconductor

41.From the combined energy-gapdiagram, which material has thewidest gap between valence band andthe conduction band?A. conductorB. semiconductorC. super conductorD. insulator

42.From the combined energy-gapdiagram, which material has the

smallest energy gap between valenceband and the conduction band?A. conductorB. semiconductorC. super conductorD. insulator

43.__________ has a unit ofelectronvolt(eV).A. ChargeB. Potential differenceC. EnergyD. Current

44.The difference in energy between thevalence and conduction bands of asemiconductor is calledA. band gapB. extrinsict photoeffectC. conductivityD. energy density

45.The energy gap between the valenceband and conduction band of aconductor is in the order ofA. zero electron volt (0 eV)B. one electron volt (1 eV)C. five electron volt (5 eV)D. ten electron volt (10 eV)

46.The energy gap of an insulator is inthe order ofA. zero electron volt (0 eV)B. one electron volt (1 eV)C. five electron volt (5 eV)D. one-tenth electron volt (0.1 eV)

47.In materials, what do you call theregion that separates the valenceand conduction bands?A. energy gapB. forbidden bandC. insulation bandD. energy gap or forbidden band

48.What do you call the potentialrequired to remove a valenceelectron?A. valence potentialB. threshold potentialC. critical potentialD. ionization potential


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49.A factor that does not affect the

resistance of the material.A. atomic structureB. massC. lengthD. cross-sectional area

50.Copper atom has how many protons?A. 1B. 4C. 8D. 29

51.Ion is __________.A. an atom with unbalanced chargesB. free electronC. protonD. nucleus without protons

52.What will happen to an atom if anelectron is either taken out ortaken into the same atom?A. Becomes negative ionB.

Becomes positive ionC. Becomes an ion

D. Nothing will happen53.When an atom gains an additional

_________, it results to a negativeion.A. neutronB. protonC. electronD. atom

54.An electrical insulator can be madea conductor by

A. ionizingB. electroplatingC. oxidizingD. metallization

55.Refers to the lowest voltage acrossany insulator that can cause currentflow.A. conduction voltageB. breakdown voltageC. voltage flowD. voltage drop

56.Dielectric is another name forA. conductor

B. semiconductorC. insulatorD. semi-insulator

57.When all atoms of a molecule are thesame, the substance is calledA. a crystalB. an elementC. a compoundD. an ion

58.An isotopeA. has a negative chargeB. has a positive chargeC. might have either positive or

negative chargeD. is neutral

59.Isotope means, the same element butwith different number ofA. electronsB. neutronsC. protonsD.

atoms

60.The particles that make up thelattice in ionic crystalA. moleculesB. ionsC. electronsD. neutrons

61.A structure for solids in which theposition of atoms are predeterminedA. CrystallineB. PolycrystallineC. LatticeD. Non-Crystalline

62.A solid, which has no definedcrystal structure.A. CrystallineB. Non-crystallineC. AmorphousD. Non-crystalline or Amorphous

63.States that each electron in an atommust have a different set of quantumnumbers.A. Quantum principleB. Fermi-Dirac principleC. Spin principle

D. Exclusion principle64.Given an atomic structure of a

certain material, what data can youdetermine out from it?A. atomic numberB. atomic massC. the number of protons and

electronsD. all of the above

65.Ideally, all atoms have the samenumber of positively charged protonsand negatively charged electrons,and is therefore considered asA. electrically neutralB. physically stableC. magnetically alignedD. technically rigid

66.When the charge of an atom becomesunbalanced, the atom is said tocarry

A.Electric chargeB. Magnetic charge

C. Electromagnetic chargeD. Electrical current

67.A charged atom is also known asA. ionB. anionC. cationD. domain

68.An atom or group of atoms thatcarries a net electric charge iscalled

A. ionB. anionC. cationD. domain

69.A negative ion results when an atomA. loss some of its inside

electronsB. loss some of its valence

electronsC. gains additional electronD. gains additional proton

70.A positive ion hasA. excess of electrons


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B. excess of neutronsC. lack of electronsD. lack of protons

71.What do you call a positivelycharged ion?A. cathodeB. anionC. cationD. domain

72.What do you call a negativelycharged ion?A. electronB. anionC. cationD. domain

73.__________ is the procedure by whichan atom is given a net charge byadding or taking away electron.A. PolarizationB. IrradiationC.

IonizationD. Doping

74.Is a process by which an atom isconstantly losing and then regainingelectrons?A. oxidationB. passivationC. metallizationD. ionization

75.The process in which atoms arechanged into ions.A. oxidationB. passivationC. metallizationD. ionization

76.Gases with charged particles.A. inertB. plasmaC. conductiveD. reactive

77.One Coulomb of charge has how manyelectrons?A. 6.24 x 1018 electronsB. 6.24 x 1019 electronsC. 62.4 x 1018 electrons

D. 62.4 x 1019 electrons78.Coulomb is the SI unit of charge,

how about in cgs?A. StatcoulombB. electron voltC. electron unitD. static unit

79.Statcoulomb is also known asA. electrostatic unit (esu)B. electron voltC. electron unitD. static unit

80.An isolated body under normalcondition is alwaysA. neutralB. positively chargedC. negatively chargedD. ionized

81.What is the charge magnitude, Q of abody if it lacks 5 electrons?A. 5 x 10-19 CoulombB. 5 CoulombC. 8 x 10-19 CoulombD. 19 x 10-19 Coulomb

82.The net movement of chargedparticles in one direction oranother.A. flowB. currentC. drift currentD. diffusion current

83.The rate at which electrons pass agiven point in the circuit gives themagnitude ofA. electron currentB. magnetic currentC. drift currentD. diffusion current

84.The unit of current.A. AmpereB. Ampere/sec.C. Ampere-sec.D. Ampere-hr.

85.The unit Ampere is equivalent toA. one Coulomb/secondB. one Coulomb/minC. one Joule/secD. one Joule/min

86.When one coulomb of electric chargecontinuously passes a given pointevery second, the electric currentis said toA. 1 AB. 1 mAC. 1 AD. 10 A

87.One ampere is equal to how manyelectrons per second?A. 1 x 1018 electrons/sec.B. 1 x 1019 electrons/sec.C. 6.25 x 1018 electrons/sec.D. 6.25 x 1019 electrons/sec.

88.The bigger the diameter of a wire,A.

more current can passB. less current can pass

C. more heat is generated whencurrent flow

D. the higher is the electricalresistance

89.If in a material, current can hardlypass, it meansA. the material is very hardB. the material is very softC. the material has high resistanceD. the material has less resistance

90.The greater the diameter of a wire,the _______ is the resistance.A. greaterB. lesserC. harderD. bigger

91.The longer the wire the ________ isthe resistanceA. higherB. lesserC. harderD. smaller


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92.If a conductors cross-sectionalarea is doubled and its length ishalved, the value of its resistancewillA. doubleB. quadrupleC. decrease by a factor of twoD. decrease by a factor of four

93.The amount of resistance that a wirehas with regards to the flow ofelectric currentA. is less for a conductor than for

an insulatorB. is less for an insulator than

for a semiconductorC. is less for a semiconductor than

for a conductorD. is high for a semiconductor than

for an insulator

94.The area of a conductor whosediameter is 0.001 inch is equal to

A.one angstromB. one circular mil

C. one micronD. one steradian

95.A 100m long wire with a cross-sectional area A=10-3 m2 has aresistance of 10. Determine the

resistivity of the wire.A. 10-2-mB. 10-3-mC. 10-4-mD. 10-5-m

96.the reciprocal of resistanceA. permeanceB. elastanceC. inductanceD. conductance

97.The science of physical phenomena atvery low temperature, approachingabsolute zero is called ________.A. crytanalysisB. cyberneticsC. temperature inversionD. cryogenics

98.What happens in the resistance ofcopper wire when its temperature israised?A. decreasedB. steadyC. increasedD. zero

99.A wire has a resistance of 5 atroom temperature and a temperaturecoefficient =4x10-3/C, calculatethe wire resistance at 75C.A. 8.925 B. 7.925 C. 6.925 D. 6.050

100. The temperature coefficient ofresistance of a certain wire isknown to be 0.004/C at zero degreesCelsius. What would be thetemperature coefficient at roomtemperature?

A.0.00018/CB. 0.00036/C

C. 0.00180/CD. 0.00360/C

101. Where does practically all ofthe RF current flow in a conductor?A. along the surfaceB. in the center of the conductorC. in the electromagnetic field in

the conductor centerD. in the magnetic field around the

conductor

102. ________ is one factor thatdoes not affect resistance.A. Cross sectional areaB. ResistivityC. MassD. Length

103. Why is the resistance of aconductor different for RF currentthan for DC?A. Because of skin effectB. Because conductors are non-

linear devices

C. Because the insulation conductscurrent at radio frequency

D. Because of the Heisenberg effect104. The ability of a material to

resist current flow is calledresistance. What is (are) thefactor(s) that affect its value?A. temperatureB. length & cross-sectional areaC. atomic structureD. all of these

105. Find the charge in coulombs ofdielectric that has a positivecharge of 14.5 x 10 to the 18th powerprotons.A. 29 x 10 to the 16th CoulombsB. 14.5 x 10 to the 16th CoulombsC. 14.5 x 10 to the 18th CoulombsD. 29 x 10 to the 18th Coulombs

106. Electron volt (eV) is a unit ofA.

powerB. energy

C. magnetic fieldD. magnetic force

107. One electron volt (eV) isequivalent toA. 1.0 watt-secB. 1.6 x 10-19 watt-secC. 1.0 JouleD. 1.6 x 10-19 Joules

108. What law that describes theforce of attraction or repulsion

between two charges is directlyproportional to their strengths andinversely proportional to the squareof the distance between them?A. Coulombs first lawB. Coulombs second lawC. Coulombs third lawD. Coulombs law or law of

electrostatics

109. What is the law whereby theforce of attraction and repulsionbetween poles is inverselyproportional to the square of thedistance between them?


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A. Newtons first lawB. Newtons second lawC. Nortons lawD. Coulombs second law

110. Is usually used to detect thepresence of electric charge.A. experimental chargeB. unit chargeC. dipoleD. test charge

111. Test charge has a charge ofA. 0 CoulombB. +1 CoulombC. -1 CoulombD. Infinity

112. Three charges of +5 C, -6 C and+7 C are placed inside a sphere,what is the total charge of thesphere?A. +5 CoulombB.

-6 CoulombC. -7 Coulomb

D. +6 Coulomb113. A combination of two charges,

with equal charge magnitude butopposite signs.A. magnetic dipoleB. static dipoleC. dynamic dipoleD. electric dipole

114. The space outside orsurrounding an electric charge where

it has a force of attraction orrepulsion.A. Electric fieldB. Magnetic fieldC. Electromagnetic fieldD. Electric flux

115. Refers to a force of field thatexists between ions where theyeither repel or attract each other.A. Resisting fieldB. Potential fieldC. DielectricD. Electromotive

116. The imaginary linesrepresenting the electric field.A. Electric fieldB. Electric fluxC. Electric flux densityD. Electric lines of force

117. What is true in visualizingelectric field lines of force from acharge body?A. Field lines are continuous curve

and they never intersect.B. The spacing between these lines

increases as they get far fromthe charged body.

C. The number of field lines isdirectly proportional to themagnitude of the electric field.

D. All of the above.118. What do you call the total

number of electric lines of force inan electric field?

A.Electric fieldB. Electric flux

C. Electric flux densityD. Electric lines of force

119. The number of lines per unitarea in a plane perpendicular to theelectric lines of force.A. Electric fieldB. Electric fluxC. Electric flux densityD. Electric lines of force

120. Electric lines of force leaveand enter the charge surface at whatangle?A. 15B. 30C. 45D. 90

121. Find the dielectric constant ofair.A. approximately 1B. approximately 0C. approximately 2D. approximately 4

122. Electric field intensity ismeasured in terms ofA. Volts/meterB. Newtons/meterC. Watts/meterD. Amperes/meter

123. Electric field intensity isA. a scalar quantityB. a vector quantityC. an absolute valueD. a relative value

124. Electric flux is a/an ________quantity.A. scalarB. vectorC. absoluteD. relative

125. Electric flux density is a/an________ quantity.A. scalarB.

vectorC. absolute

D. relative126. Three charges of +5 C, -6 C,

and +7 C are inside a sphere, whatis the total electric flux passingthrough the surface of the sphere?A. 5 CoulombsB. 6 CoulombsC. 7 CoulombsD. 8 Coulombs

127. An electric charge produces atotal electric field of 6 Coulombs,calculate the electric flux densityin an area of one square meter(1m2).A. 1 C/m2B. 2 C/m2C. 4C/m2D. 6C/m2

128. The measure of density of theelectric chargeA. Electric gradientB. Electric currentC. Electric chargeD. Electric potential


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129. The ability of the material to

store electrical potential energyunder the influence of an electricfield.A. capacityB. permeabilityC. permittivityD. conductivity

130. The absolute permittivity ofair or free space.A. 1/36 x 10-9 F/mB. 36 x 10-9 F/mC. 1/36 x 10-19 F/mD. 36 x 10-19 F/m

131. The relative permittivity ofair.A. 0B. 1C. 1/36 x 10-9 F/mD. 8.854 x 10-12 F/m

132. Calculate the permittivity of amaterial with relative permittivityof 5.A. 8.854 x 10-11 F/mB. 4.42 x 10-11 F/mC. 1/36 x 10-9 F/mD. 8.854 x 10-12 F/m

133. What is the term used toexpress the amount of electricalenergy stored in an electrostaticfield?A. VoltsB. WattsC. CoulombsD. Joules

134. How does permittivity affectelectric field intensity?A. It causes the field intensity to

increase.B. It causes the field intensity to

decrease.C. It causes the field intensity to

fluctuate up and down.D. It has no effect on field

intensity.

135. Relative permittivity is alsoknown asA. dielectric constantB. dielectric strengthC. isolation strengthD. permeability

136. Most materials relativepermittivity lies betweenA. 0.01 1B. 1 10C. 10 50D. 50 100

137. Charge body at rest is said toexhibit electric field, whichinteracts with other bodies. Thestudy of this phenomena is known asA. electricityB. electrostaticsC. electromagnetismD. field interactions

138.

The basic law for interactionof charged bodies at rest.A. Charged lawB. Gauss lawC. Faradays lawD. Coulombs law

139. The force between the twoelectrically charged body is calledA. electromotive forceB. electrostatic forceC. electromagnetic forceD. magnetic force

140. The force between twoelectrically charged body isA. directly proportional to the

chargeB. inversely proportional to the

chargeC. not affected by the chargeD. universally constant

141. In 1784, who demonstrated thatthe force between charges isinversely related to the square ofthe distance between them?A. MaxwellB. Gauss

C. TeslaD. Coulomb

142. Determine the force in Newtonbetween 4C charges separated by 0.1

meter in air.A. 1.44 NB. 14.4 NC. 144 ND. 1440 N

143. What will happen when twoopposite charges get closer?A. repels lessB. attracts lessC. repels moreD. attracts more

.144. The value of k in Coulombs

electrostatic force equation ( F =kQ1Q2/r

2 ) is oftentimes expressed as1/4. What is ?A. absolute permeabilityB.

absolute permittivityC. relative permeability

D. relative permittivity145. The measure of electric field

strength per unit length is known aselectric field intensity or simplyelectric intensity. What is itsunit?A. Volt/meter (V/m)B. Joules/Coulomb-meter (J/Cm)C. Newton/Coulomb (N/C)D. All of the above

146. Calculate the electric fieldintensity 10cm from a charge Q=5nC.A. 450 N/CB. 900 N/CC. 4.5 x 103 N/CD. 9.0 x 103 N/C

147. Determine the magnitude of theelectric field inside a sphere thatencloses a net charge of 2C.A. 0 (zero)B. 9 x 107 N/CC. 1.8 x 108 N/CD. infinite


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148. Calculate the total electricfield at the surface of a sphere ofradius r=1cm, and enclosing a netcharge of 2C.A. 0 (zero)B. 9 x 107 N/CC. 1.8 x 108 N/CD. infinite

149. A 2nC point charge will producewhat potential at 2m away?A. 4.0 VoltsB. 6.0 VoltsC. 7.5 VoltsD. 9.0 Volts

150. A charged body in free spaceproduces 10-V potential at adistance 25cn away. What will be thepotential at 50cm away?A. 5.0 VoltsB. 7.5 VoltsC. 10.0 VoltsD.

15.0 Volts

electricity fundamentals

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