Thechargeofeach(Positive,Negative,Orneutral)

Review1

1.Listthethreebasicelementsofanatomandstate

thechargeofeach(positive,negative,orneutral).

ElementCharge

2.Anelectronforced out of orbitbyanexternalforce is

called a ______.

3.Conductorsallow______freeelectronstoflow

when an external electric force is applied.

4.Whichofthefollowingmaterialsaregood

conductors?

a.coppere.aluminum

b.plasticf.glass

c.silverg.iron

d.rubberh.mica

5.Semiconductor devices can bemanufactured to

allow______electronstoflowinonedirection

and______electrons toflowintheopposite

direction

177

Review2

1.Elementsareidentifiedbythenumberof

______in orbitaround the nucleus.

2.Amaterial that has anexcessofelectronsissaidto

have a ______charge.

3.A material that has a deficiency of electrons is said

tohave a______charge.

4.Likecharges ______and unlike charges

______.

5.The forcethat is appliedtoaconductor tocause

currentflow is ______.

6.Electronsmovefrom______.

a.positivetonegative

b.negativetopositive

7.With anincreaseof length or a decreaseofcross-

sectionofaconductor,resistancewill______.

a.increase

b.decrease

178

Review3

1.ThebasicOhm’sLawformulais______.

2.Whensolvingcircuitproblems;

current must alwaysbeexpressedin______,

voltagemust always be expressedin ______,

andresistancemustalwaysbeexpressedin______.

3.Thetotalcurrentofasimplecircuitwithavoltage

supply of12voltsand a resistanceof24 Wis______amps.

4.Whatisthetotalresistanceofaseriescircuitwith

followingvalues:R1=10W, R2=15W,andR3=20W?

______W.

5.What is total current of a series circuit that has a 120

volt supply and60Wresistance?

6.Inthefollowingcircuit,thevoltagedroppedacross

R1is______voltsandR2is______volts.

1.5Ω1.5Ω

R1R2

+

_

12 Volts

7.Inthefollowingcircuit,voltagedroppedacrossR1is

______voltsandacrossR2is______.

5Ω2Ω

R1R2

+

_

100 Volts

179

Review4

1.Thetotal resistanceofaparallelcircuitthathasfour

20W resistors is ______Ω.

2.Rtforthefollowingcircuitis______Ω.

R2R2R3

10Ω20Ω30Ω

3.Rtforthefollowingcircuitis______Ω.

R1R2

5Ω10 Ω

4.VoltageavailableatR2 inthe followingcircuitis

______volts.

12 Volts

R1R2

5Ω10 Ω

5.In a parallel circuit with two resistors of equal value and

atotalcurrentflowof12amps,thevalueofcurrent

througheachresistoris______amps.

6.Inthefollowingcircuit,currentflowthroughR1is_____

______amps,andthroughR2is______amps.

24Volts

R1R2

10 Ω15 Ω

180

Review5

1.Calculate equivalent resistance forR1 and R2 and total

resistancefortheentirecircuit.

R120Ω

R310Ω

+

_R230Ω

R1,R2equivalentresistance=______Ω

Totalresistance=Ω

2.Calculate equivalent resistance forR1 and R2 and total

resistancefortheentirecircuit.

R130Ω

+

_R320Ω

R210Ω

R1,R2equivalentresistance=______Ω

Totalresistance=______Ω

181

Review6

1.The rate at whichwork is done is called

______.

2.The basicformulas forpowerinaDCcircuitare:

P=Ix__,P=I2x__,andP= _

R

3.In a circuit with a 12 volt supply and 4Wresistance,the

powerconsumedis______watts.

4.The two characteristics of all magnets are: they attract

andhold______,and,iffreetomove,theywill

assumeroughlya______position.

5.Linesoffluxalwaysleavethe______poleand

enterthe______pole.

6.The left-hand rule for conductors states that, when

the______handisplacedonacurrent-carrying

conductorwiththe______pointinginthe

directionofelectronflow,thefingerswillpointinthe

direction of ______.

182

Review7

1.A______isthe graphicrepresentationofAC

voltageor currentvaluesovertime.

2.Each phaseofthreephaseACpower isoffset by

______degrees.

3.AnACgeneratorproduces______cycle(s)per

revolution foreachpairofpoles.

4.What is the instantaneousvoltage at 240degrees fora

sinewave with a peak voltageof 150volts?

5.Whatistheeffectivevoltageforasinewavewitha

peak voltageof150volts?

183

Review8

1.The total inductance for this circuit is ______mh.

4mh2mh3mh

L1L2L3

2.Thetotalinductanceforthiscircuitis______mh.

L1L2

5mh10 mh

3.Thetotalcapacitanceforthiscircuitis______mF

5µF10 µF10 µF

C1C2C3

4.Thetotalcapacitanceforthiscircuitis______mF

C1C2C3

5µF10 µF10 µF

Review9

1.OppositiontocurrentflowinanACcircuit causedby

inductorsandcapacitorsiscalled______.

2.TotaloppositiontocurrentflowinanACcircuitwith

both resistance andreactanceiscalled ______.

3.In a50 hertz circuit,containinga 10mhinductor, the

inductivereactanceis______ohms.

4.Inapurelyinductivecircuit,______

a.currentandvoltageareinphase

b.current leads voltage by90degrees

c.current lagsvoltageby90degrees

5.Inapurelycapacitive circuit, ______

a.currentandvoltageareinphase

b.current leads voltage by90degrees

c.current lagsvoltageby90degrees

6.In a50hertz circuit,containinga10microfarad

capacitor,thecapacitivereactanceis______

ohms.

7.Inacircuitwith5W resistance,and10Winductive

reactance,impedanceis______ohms.

8.Inacircuitwith5Wresistance,and4Wcapacitive

reactance,impedanceis______ohms.

185

Review 10

1.AnACcircuitis______ifinductivereactanceand

capacitivereactanceareequal.

2.AseriesACcircuitis______ifthereismore

inductivereactancethancapacitivereactance.

3.AseriesACcircuitis______ifthereismore

capacitivereactancethaninductivereactance.

4.In a120VAC,60hertzseriescircuit, with1000W

of resistance, 10 mhof inductance and4 mF of

capacitance,impedanceis______Wandcurrent

is______amps.

5.For the followingcircuit,calculateimpedanceand

current.

R=1000 ΩXL=200ΩXC=1200Ω

120V

60Hz

Impedance is______W,andItis______amps.

6.Foracircuitwitha120voltACsourceandacurrentof

10amps,theapparentpoweris______VA.

7.For a circuitwithanapparentpowerof3000VAanda

power factor of0.8,thetruepoweris______watts.

186

Review11

1.Iftheprimaryof atransformer hasmoreturnsthanthe

secondary,itisa______transformer.

2.If theprimaryofatransformer hasfewerturnsthanthe

secondary,itisa______transformer.

3.The secondary voltageofaniron-coretransformerwith

240 volts on theprimary,40 ampsontheprimary,and

20 ampsonthesecondaryis______volts.

4.A transformer witha 480volt,10 ampprimary,anda

240 volt, 20 amp secondary will be rated for

______kVA.

5.A wyeconnected,three-phasetransformersecondary,

with240 voltsline-to-linewillhave______volts

line-to-neutral.

187

189Review1

1. Listthethreebasicelementsofanatomandstate

thechargeofeach(positive,negative,orneutral).

ElementCharge

1. Anelectronforced out of orbitbyanexternalforce is

called a ______.

1. Conductorsallow______freeelectronstoflow

when an external electric force is applied.

1. Whichofthefollowingmaterialsaregood

conductors?

a.coppere.aluminum

b.plasticf.glass

c.silverg.iron

d.rubberh.mica

1. Semiconductor devices can bemanufactured to

allow______electronstoflowinonedirection

and______electrons toflowintheopposite

direction

1. What are three good electrical conductors?

1. Copper, gold, mica
2. Gold, silver, wood
3. Gold, silver, aluminum
4. Copper, aluminum, paper

1. What are four good electrical insulators?

1. Glass, air, plastic, porcelain
2. Glass, wood, copper, porcelain
3. Paper, glass, air, aluminum
4. Plastic, rubber, wood, carbon

1. What does an electrical insulator do?

1. It lets electricity flow through it in one direction
2. It does not let electricity flow through it
3. It lets electricity flow through it when light shines on it
4. It lets electricity flow through it

1. The particles that orbit around the center of an atom are

1. Electrons.
2. Molecules.
3. Nucleus.
4. Protons.

1. An atom which loses or gains one electron is called:

1. Balanced.
2. An element.
3. A molecule.
4. A charged particle or ion.

1. The proton carries a single unit positive charge equal in magnitude to the electron charge.

1. True
2. False

1. The electrons attraction to the nucleus is called______.

1. electrostatic field
2. electrostatic attraction
3. electrostatic force
4. potential difference

1. Atoms with only one valence electron make good______.

1. Insulators
2. Semiconductors
3. Conductors
4. Resistors

1. The electrons in the outermost shell are called valence electrons.

1. True
2. False

1. An electron has a ______charge.
2. Positive
3. Negative
4. Neutral

1. In a stable atom, the number of positively charged particles is ______to the number of negatively charged particles.

a.Equal to

b.Greater than

c.Less than.

1. The positively charged particle of an element is a ______

1. Atom
2. Electron
3. Proton
4. Neutron

1. The center of the atom, the nucleus, is made up of the following

1. Electrons
2. Protons
3. Neutrons
4. All of the answers provided

1. Materials that easily move electrons are:

1. Atoms
2. Conductors
3. insulators resistors
4. all of the answers provided

1. If positive and negative bodies are joined together by a copper wire, the following would happen.

1. An atomic explosion
2. Nothing
3. Electrons would move in the wire from the negative charged body to positive charged body
4. Electrons would move in a wire from the lower charged body to the higher charged body

1. As the number of electrons in the outer orbit increases, the atoms change in behavior from a ______to a ______.

1. Conductor / insulator
2. Insulator/ conductor
3. No change either case

1. Which of the following is NOT an insulator?

1. Electrical tape
2. Copper wire
3. Plastic
4. Glass

1. Like charges ______.

1. Repel
2. Attract
3. have no effect on each other
4. none of the answers provided

1. In which ways can electricity be produced?

1. Chemical - batteries
2. Thermal
3. Photo-electric
4. Magnetically – mechanically generated
5. All of the answers provided

Review2

1. Elementsareidentifiedbythenumberof

______in orbitaround the nucleus.

1. Amaterial that has anexcessofelectronsissaidto

have a ______charge.

1. A material that has a deficiency of electrons is said

tohave a______charge.

1. Likecharges ______and unlike charges

______.

1. The forcethat is appliedtoaconductor tocause

currentflow is ______.

1. Electronsmovefrom______.
2. positivetonegative

1. negativetopositive

1. With anincreaseof length or a decreaseofcross-

sectionofaconductor,resistancewill______.

a.increase

b.decrease

1. What is electricity?
2. Charged matter.
3. Moving electrons.
4. Positive charge.
5. Negative charge.

1. What is static electricity?

1. Ionized atoms.
2. Electricity at rest.
3. Charged particles.
4. Attraction and repulsion.

1. Which of the following materials makes the best electromagnet?
2. Copper.
3. Stainless steel.
4. Soft iron.
5. Silver.

1. What is the symbol for alternating current?
2. DC.

1. Hz.
2. F.
3. AC.

1. How did alternating current get its name?
2. From the person who developed it.
3. From the electrons move in one direction and then move back in the other direction.
4. From the constant current.
5. From the constant voltage.

1. Which of the following statements best describes the current Characteristics of an AC system?

1. The electrons move through a circuit in one direction for a period of time, and then move back in the other direction for a like period of time.
2. The electrons move from a point of low potential to a point of high potential.
3. The voltage in an AC circuit never changes polarity.
4. The electrons move through a circuit in one direction for a period of time, and then move back in the other direction for a period of time twice as long.

1. What is the name for the flow of electrons in an electric circuit?

1. Voltage
2. Resistance
3. Capacitance
4. Current

1. What is the basic unit of electric current?

1. The volt
2. The watt
3. The ampere
4. The ohm

1. Which instrument would you use to measure electric current?

1. An ohmmeter
2. A wave meter
3. A voltmeter
4. An ammeter

1. What is the name of the pressure that forces electrons to flow through a circuit?

1. Magneto motive force, or inductance
2. Electromotive force, or voltage
3. Farad force, or capacitance
4. Thermal force, or heat

1. What is the basic unit of electromotive force (EMF)?

1. The volt
2. The watt
3. The ampere
4. The ohm

1. How much voltage does an automobile battery usually supply?

1. About 12 volts
2. About 30 volts
3. About 120 volts
4. About 240 volts

1. How much voltage does a wall outlet usually supply (in the Kuwait)?

1. About 12 volts
2. About 30 volts
3. About 120 volts
4. About 240 volts

1. Which instrument would you use to measure electric potential or electromotive force?

1. An ammeter
2. A voltmeter
3. A wave meter
4. An ohmmeter

1. What limits the current that flows through a circuit for a particular applied DC voltage?

1. Reliance
2. Reactance
3. Saturation
4. Resistance

1. What is the basic unit of resistance?

1. The volt
2. The watt
3. The ampere
4. The ohm

1. Which instrument would you use to measure resistance?

1. An ammeter
2. A voltmeter
3. An ohmmeter
4. A wave meter

1. The unit of current is ______.

1. ampere

1. watt

1. volt

1. coulomb

1. The device used for measuring potential difference is known as ______.

1. potentiometer

1. ammeter

1. galvanometer

1. voltmeter

1. The current in a wire ______.

1. depends only on the potential difference applied

1. depends only on the resistance of the wire

1. depends on both resistance and potential difference

1. does not depend on resistance and potential difference

1. When there is an electric current passing through a wire, the particles moving are ______.

1. electrons

1. protons

1. atoms

1. ions

1. The resistivity of a wire depends on ____.

1. length

1. material

1. area of cross- section

1. all the above

1. Which effect of current is used in the following appliance?

1. Electric bulb
2. immersion rod
3. electric iron
4. galvanometer

Answer: For electric bulb, immersion rod and electric iron, heating effect of current is used. For galvanometer magnetic effect of current is used.

1. On what factors does the heating effect of current depend on?

Answer: The heating effect of current depends on

• The square of the amount of current flowing
• The resistance of the wire and
• The time of flow of current

1. Name the instrument that measures the potential difference across the ends of a current carrying conductor. How is the instrument connected to the circuit?

Answer: Voltmeter measures the potential difference across the ends of a conductor. It is connected in

Parallel across the element, through which current flows due to a certain potential difference.

1. The conventional theory of current flow says that current flows:

1. Randomly.
2. Positive to negative.
3. Negative to positive.
4. None of the above.

1. The force that causes electrons to flow through a conductor is known as:

1. The power.
2. The current.
3. The voltage.
4. The resistance.

1. A break or interruption in an electrical circuit is:

1. An open.
2. A short.
3. A ground.
4. None of the above.

1. The specified voltage output from an electrical device is 0.55 volts. Technician A says this is equivalent to 5.5 millivolts. Technician B says it is equivalent to 550 millivolts. Who is correct?

1. Technician A.
2. Technician B.
3. Both Technicians A & B.
4. Neither Technicians A nor B.

1. A material in which there are no free charge carriers is known as

1. conductor

1. insulator

1. Charges

1. The Electrostatic Field is force acting between charged objects that causes them to repel or attract.

1. True
2. False

1. To produce current, the electrons must be moved by a potential difference.

1. True
2. False

1. Conventional Current Flow is current flow from positive to negative potentials.

1. True
2. False

1. Electron current, or amperage, is described as the movement of free electrons through a conductor.

1. True
2. False

1. Resistance is defined as all opposition to current flow.

1. True
2. False

1. Which of the following is not a basic part of an electric circuit?

1. Fuse
2. Source of Power
3. Load
4. Switch
5. Conductors

1. The units used to measure resistance are ______.

1. Ohms
2. Volts
3. Amps

1. Electrical potential is measured in:

1. Ohms
2. Volts
3. Watts
4. Amps
5. none of the answers provided

1. Using a volt meter, you will get a voltage reading when taking a measurement across an electrical power source.

1. True
2. False

1. Using a volt meter, you will get a voltage reading when taking a measurement across an electrical load.

1. True
2. False

Review3

1. ThebasicOhm’sLawformulais______.

1. Whensolvingcircuitproblems;

current must alwaysbeexpressedin______,

voltagemust always be expressedin ______,

andresistancemustalwaysbeexpressedin______.

1. Thetotalcurrentofasimplecircuitwithavoltage

supply of12voltsand a resistanceof24 Ω is______amps.

1. Whatisthetotalresistanceofaseriescircuitwith

followingvalues:R1=10Ω, R2=15Ω,andR3=20Ω?

______Ω.

1. What is total current of a series circuit that has a 120

volt supply and60Ω resistance?

1. Inthefollowingcircuit,thevoltagedroppedacross

R1is______voltsandR2is______volts.

1.5Ω1.5Ω

R1R2

+

_ 12 Volts

1. Inthefollowingcircuit,voltagedroppedacrossR1is

______voltsandacrossR2is______.

5Ω2Ω

R1R2

+

_ 100 Volts

1. Who discovered that current is directly proportional to the voltage and inversely proportional to the resistance?
2. Kirchhoff.
3. Ampere.
4. Voltaire.
5. Ohm.

1. What is the applied voltage in a series circuit composed of a battery, and three resistors whose voltage drops are ER1 = 10V, ER2 = 5V, ER3 = 15V. Use Kirchhoff's Voltage Law.

a.20 V.

b.25 V.

c.15 V.

d.30 V.

1. What is the formula for total current in a series circuit?
2. IT = E1/R1 + E2/R2 + E3/R3.
3. IT = I1 - I2 - I3.
4. IT = I1 + I2 + I3.
5. IT = I1 = I2 = I3.

1. Which of the following statements does not represent ohm's law?

1. current / potential difference = constant

1. potential difference / current = constant

1. potential difference = current x resistance

1. current = resistance x potential difference

1. The potential difference required to pass a current 0.2 A in a wire of resistance 20 Ω is ____.

1. 100 V

1. 4 V

1. .01 V

1. 40 V

1. The resistance of an electric bulb drawing 1.2 A current at 6.0 V is ______.

1. 0 .5Ω

1. 5Ω

1. 0.2Ω

1. 2Ω

1. Three equal resistances when combined in series are equivalent to 90Ω. Their equivalent resistance when combined in parallel will be ______.

1. 270Ω

1. 30Ω

1. 810Ω

1. 10Ω

1. Ohm's law relates current inversly with ______.

1. power

1. resistance

1. potential difference

1. time

1. State ohm's law.

Answer: When temperature and other physical parameters remain constant, the current flowing

through a conductor is directly proportional to the potential difference across its ends.

1. Which of the following graphs depict ohm's law?

Answer:Graph (a) represents ohm's law since a straight line which shows that 'I' is directly proportional to 'V'.

1. The sum of voltage drops in a series circuit equals the:

1. Voltage across the largest load.
2. Voltage across the smallest load.
3. Source voltage.
4. Shunt circuit voltage.

1. The relationship between voltage (V), current (I) and resistance (R) for a resistor is:

1. V = IR

1. V = R/I
2. V = IR * R

1. A potential difference of 7.5 V appears across a 15-ohm resistor. Which of the following is the current through the resistor?

1. 0.25 A
2. 0.5 A
3. 2 A

1. In 1827, George Simon Ohm discovered that there was a definite relationship between voltage, current, and resistance in an electrical circuit.

1. True
2. False

1. In the formula for Ohms law, what does the letter E stands for?

1. Volts
2. Ohms
3. Amps

1. In the formula for Ohms law, what does the letter I stands for?

1. Volts
2. Ohms
3. Amps

1. In the formula for Ohms law, what does the letter R stands for?

1. Volts
2. Ohms
3. Amps

1. Using the above formula for ohms law, write the equation for finding Volts

1. E = I x R
2. E = I / R
3. E = R / I
   

1. Using the above formula for ohms law, write the equation for finding Current

1. I = E / R
2. I = E x R
3. I = R/E

1. Using the above formula for ohms law, write the equation for finding Resistance

1. R = E / I
2. R = E x I
3. R= I/E

1. Given E = 208 volts, R = 121 ohms, I = ______

1. 1.7 amps
2. 0.58 amps
3. 25.2 amps
4. none of the answers provided

1. Given: R = 10 ohms, I= 48 amps, what is the voltage?

1. 480v
2. 208v
3. 240v
4. 120v

1. Given: Voltage = 120 volts, Amps = 15, R = ______

1. 80 ohms
2. 8 ohms
3. 1800 ohms
4. none of the answers provided

1. In a series circuit, how many paths are there for current to flow?

1. One Path
2. Two separate paths
3. 3 separate paths

Review4

1. Thetotal resistanceofaparallelcircuitthathasfour

20Ω resistors is ______Ω.

1. Rtfor thefollowingcircuitis______Ω.

R2R2R3

10Ω20Ω30Ω

1. Rtforthefollowingcircuitis______Ω.

R1R2

5Ω10 Ω

1. VoltageavailableatR2 inthe followingcircuitis

______volts.

12 Volts

R1R2

5Ω10 Ω

1. In a parallel circuit with two resistors of equal value and

atotalcurrentflowof12amps,thevalueofcurrent

througheachresistoris______amps.

1. Inthefollowingcircuit,currentflowthroughR1is_____

______amps,andthroughR2is______amps.

24Volts

R1R2

10 Ω15 Ω

1. What is the formula for Kirchhoff's current for a circuit with three parallel resistors?
2. IT = I1 = I2 = I3.
3. IT = E/R.
4. IT = I1 + I2 + I3.

1. What is the formula for two or more unlike resistors in parallel?
2. RT = E/R1.
3. RT = R1/N.
4. 1/RT = 1/R1+1/R2+1/R3

1. Two coils have a combined resistance of 25 when connected in series and a resistance of 4 when connected in parallel. What is the resistance of each coil?

Answer: Let the resistance be R1and R2, and Rsrepresents resistances in series and Rprepresents

resistance in parallel.
According to the given data
R1+R2=RS=25______( 1)
+ = =
______( 2)
R1+ R2= 25
R1R2= 100
(R1- R2)2= (R1+ R2)2- 4 R1R2
= 252- 4 (100)
= 625 - 400
= 225
R1- R2= 15
R1+ R2= 25
Adding

2R1= 40
R1= 20

R2= 5

1. Four cells each of e.m.f = 'E' are joined in parallel to form a battery. The equivalent e.m.f of the battery will be ______.

1. 4 E
2. E
3. E / 4
4. E = 0

Answer: c

1. When are several resistors in a circuit said to be connected in parallel?

Answer: Several resistors are said to be connected in parallel when the potential difference across the resistors remain the same.

1. Two identical lamps are connected in parallel to a 12-volt source. The voltage across each lamp is:

1. 12 volts.
2. 6 volts.
3. 4 volts.
4. 2 volts.

1. In a parallel circuit which of the following is true:

1. Circuit resistance decreases as additional branches are added.
2. Current is equal in all parts of the circuit.
3. Only one current path to ground.
4. None of these

1. Several lamps are connected in parallel to a voltage source. If one light burns out, all the other lamps:

1. Will go out.
2. Will get brighter
3. Will not be affected.
4. Will get dimmer.

1. In a Parallel circuit, how many paths are there for current to flow?

1. One Path
2. Two or more separate paths

1. What is the formula for Kirchhoff's current for parallel circuits?

1. IT = I1 = I2 = I3.
2. IT = E/R.
3. IT = I1 + I2 + I3.
4. IT = I1 2 + I2.

Review5

1. Calculate equivalent resistance forR1 and R2 and total

resistancefortheentirecircuit.

R120Ω

R310Ω

+

_ R230Ω

R1,R2equivalentresistance=______Ω

Totalresistance=______Ω

1. Calculate equivalent resistance forR1 and R2 and total

resistancefortheentirecircuit.

R130Ω

+

_ R320Ω

R210Ω

R1,R2equivalentresistance=______Ω

Totalresistance=______Ω

1. Three resistors 2Ω, 3Ωand 4Ωare connected so that the equivalent resistance is 9Ω.

The resistors are connected ______.

1. all in series
2. all in parallel
3. 2Ω and 3Ω in parallel and the combination in series with 4Ω
4. 2Ω and 3Ω in series and the combination in parallel to 4Ω

1. In the figure,
   

1. 6Ω, 3Ω and 9Ω are in series
2. 9Ω and 6Ωare in parallel and the combination is in series with 3Ω
3. 3Ω, 6Ω and9 Ω are in parallel
4. 3Ω, 6Ω are in parallel and 9Ω is in series

1. The resistance across AB is
   

1. 4 Ω
2. 1 Ω
3. 2 Ω
4. 0.5 Ω

1. A series/parallel circuit is represented by illustration ______.

1. 1
2. 2
3. 3

1. A parallel circuit is represented by illustration ____.

1. 1
2. 2
3. 3

1. A series circuit is represented by illustration _____.

1. 1
2. 2
3. 3

1. A fuse is added to the circuit to protect the circuit and the other loads.

1. True
2. False

Review6

1. The rate at whichwork is done is called

______.

1. The basicformulas forpowerinaDCcircuitare:

P=Ix__

P=I2x__

P= _

R

1. In a circuit with a 12 volt supply and 4 Ω resistance,the

powerconsumedis______watts.

1. The two characteristics of all magnets are: they attract

andhold______,and,iffreetomove,theywill

assumeroughlya______position.

1. Linesoffluxalwaysleavethe______poleand

enterthe______pole.

1. The left-hand rule for conductors states that, when

the______handisplacedonacurrent-carrying

conductorwiththe______pointinginthe

directionofelectronflow,thefingerswillpointinthe

direction of ______.

1. What is one important characteristic of magnetic lines of force?
2. Magnetic lines of force are conducted by all materials.
3. Magnetic lines of force are conducted by some materials.
4. Magnetic lines of force move perpendicular to each other.
5. Magnetic lines of force are attracted by air.

1. What is the unit of electrical power?
2. Watt.
3. Ampere.
4. Ohm.
5. Volt.

1. What current would flow through a 5,000 Ωresistor that is dissipating 50 W of power?

1. 100 mA.
2. 101 A.
3. 10 mA.
4. 100 A.

1. Aschematicshowsfive(5)identicalresistorsconnectedinparallelacrossa230Vacsourceasananti-condensationheaterforalargemotor.Theinstructionmanualstatesthattheentireanti-condensationheatercircuitrequires350watts.Whatshouldbethevalueofeachoftheresistors:
2. 30ohms
3. 151ohms
4. 327ohms
5. 755ohms

1. Which of the following is another name for the magnetic lines of force?

1. CEMF.
2. EMF.
3. Flux.
4. Conductor.

1. A passenger cabin has 110 passenger reading lamps each rated at 10W, 28V. What is the maximum load current imposed by these lamps?

1. 25.5 A
2. 39.3 A
3. 308 A

1. When a current 'I' flows through a resistance 'R' the electrical Power is given by ______.

1. I R
2. I2R
3. I R2
4. I2 / R

1. Kilowatt - hour is the unit of ______.

1. potential difference
2. electric power
3. electrical energy
4. charge

1. When a fuse is rated 8 A, it means ______.

1. it will not work if current is less than 8 A
2. it has a resistance of 8 W
3. it will work only if current is 8 A
4. it will melt if current exceeds 8 A

1. The work done in moving a unit positive charge across two points in an electric circuit is a measure of ______.

1. current
2. potential difference
3. resistance
4. Power

1. Joule / Coulomb is same as ______.

1. Watt

1. Volt

1. ampere

1. Ohm

1. The strength of the magnetic field that surrounds a single conductor with current flowing though it?

1. Is usually weak.
2. Varies directly with the amount of current flowing through the conductor.
3. Can be detected using a magnetic compass.
4. All of these.

1. When the lines of a magnetic force cut across a conductor:

1. A voltage is induced into the conductor.
2. The conductor is permanently induced.
3. The conductor is permanently magnetized.
4. Magnetism is induced into the conductor.

1. Which of the following factors does NOT affect the strength of an electromagnet?

1. The type of core.
2. The direction of the windings.
3. The amount of current flow.
4. The number of turns in the coil.

1. When electrical current is passed through a conductor that is forced into many loops, a magnetic field is created. The strength of the field may be increased by

1. Increasing the turns or coils of the conductor.
2. Increasing the amount of the current in the coils.
3. Both A and B.
4. Neither A nor B.

1. Magnets are surrounded with lines of force that are called flux.

1. True
2. False

1. Two positive magnetic poles attract each other.

1. True
2. False

1. As the current increases in a wire, the strength of the magnetic field

1. decreases
2. does not change
3. increases
4. is not influenced by current flow

1. If you reverse the current flow in a wire the magnetic lines of force will not rotate in the opposite direction.

1. True
2. False

1. When a wire is moved through a magnetic field, electricity flows in the wire.

1. True
2. False