A+ + + - + + ++ + - - + + ++ + + - - + +

B+ - + - + - + -- + - + - + - ++ - + - + - + -

C- - - + + - - - - - + + + - - - + - - - - + -

ELECTRICAL PRINCIPLES AND TECHNOLOGIES REVIEW QUESTIONSFORMULAS :

R = V P = E P = V x I I t

Use this diagram to answer the next question.

1. Within the casing, electricity is produced as a result of

A. a coil of wire spinning around an insulatorB. a coil of wire spinning within a magnetic fieldC. an insulator spinning around a coil of wireD. magnets spinning within an electric field

2. A furnace switch works using a bi-metallic strip connected to a circuit. The metal on one side expands more than the metal on the other side when it is heated. When it reaches a certain temperature, it has bent enough to break the circuit and the furnace shuts off. This type of switch is called a

A. thermocoupleB. thermopileC. thermometerD. thermostat

Use this diagram to answer the next question.

3. Which of these objects would be attracted to “A”?

A. BB. CC. B and CD. Neither B or C

Use this diagram to answer the next question.

4. The diagram above is a schematic drawing of a circuit consisting of four switches and three bulbs. If switches A and C are closed, and switches B and D are open, then

A. none of the bulbs will light upB. bulbs 1 and 3 will light upC. bulbs 2 and 3 will light upD. only bulb 2 will light up

5. The current running through a coffee maker connected to a 120 V source is 8 A. What is the power rating of the coffee maker?

A. 15 WB. 128 WC. 0.07 WD. 960 W

The following are possible sources of energy to convert to electrical energy. If the source is renewable, write a “1” in the space. If the source is non renewable, write a “2” in the space.

_____ burning biomass _____ burning coal _____ nuclear _____ ocean tides

Numerical Response

1

6. The schematic diagram that shows the circuit that would work best to power an electric drill would be

7. Sarah wanted to make sure that her new hair dryer was efficient since she was concerned about wasting electricity. 500 kJ of energy was required to operate the hair dryer for 5 minutes. During that time,

it would produce 370 kJ of useful output energy. If efficiency = output/input x 100, the efficiency of the hair dryer is

A. 85%B. 74%C. 55%D. 14%

Use this information to answer the next question.

A builder wanted to be able to turn on and off lights from two different locations in the cabin he was building. He drew a circuit diagram using these symbols.

8. Which of the following circuit diagrams would work?

9. An energy conversion from gravitational to mechanical to electrical energy takes place in a/an

A. steam powered turbineB. nuclear power plantC. thermoelectric plantD. hydroelectric dam

Use this information to answer the next numerical response question.

\

An electric motor depends on several different components to convert electrical energy into mechanical energy. Given below are four components found in an electric motor.

Term number Term1 Armature2 Brush3 Commutator4 Coil

Numerical Response

Match each term number with its proper function in the electric motor.

_____ a split ring that breaks the flow of electricity and then reverses the connection to the power source _____ bars, usually made of carbon, that connect the energy source to the moving parts of the electric motor _____ a solid rotating shaft found inside the motor

_____ wire found inside the electric motor that acts as an electromagnet when electricity is passed through the wire

2

Use this diagram to answer the following question.

10. What will be the result if bulb F is removed from its socket?

A. All other devices will stop working.B. All other devices will continue to work.C. Only devices F, G and H will stop working.D. Only devices F, G, and H will continue working.

Use this information to answer the following questions.

11. Based on this data, the most pure distilled water would be

A. Sample 1B. Sample 2C. Sample 3D. Sample 4

A technician has four samples of distilled water and wants to determine which sample is the purest by measuring the conductivity of each (knowing that pure distilled water is a very poor conductor). The table below shows her data.

Sample Resistance (Ω)1 0.52 3.73 1.24 2.6

12. While checking all the fuses and circuit breakers, you notice that in the electrical panel, a 20 A fuse has been placed in the circuit designed for a 15 A fuse. This is a dangerous situation because

A. the fuse does not fit properlyB. the fuse may cause an electrical shockC. an increase in electrical current may cause the fuse to tripD. an increase in electrical current may cause the wires to overheat

Use this information to answer the following question.

13. The correct analogy would be

14. In the circuit shown here, the load would be the

A. batteryB. lampC. motorD. wire

Use this information to answer the next numerical response question.

Some Forms of Energy

1. Electrical2. Mechanical3. Light

Tim needed to pass a box of tennis balls through two pipes to his partner as quickly as possible in order to win a race. One pipe was much thinner than the other. Tim pushed the balls through both pipes as fast as he could but it was much easier through the larger pipe.

4. Gravitational

The potential energy in a river can be used to provide electricity. List the energy forms, as numbered above, in the sequence in which they would occur as they change from one form to another to become usable energy.

__________ to __________ to __________ to __________ river water usable energy

15.While servicing an ATV, a mechanic checks to see if the headlights provide sufficient light. Which of the following diagrams illustrates a circuit that would provide the brightest lights for an ATV?

Use this information to answer the following question.

The following table shows the voltage from a number of combinations of electrodes and electrolytes tested in a wet cell experiment.

Numerical Response

3

16. The best materials to use would be

Electrolyte ElectrodesA.

HCl Zinc, Aluminum

B.

Lemon juice Zinc, Lead

C.

Water Copper, Copper

D.

HCl Copper, Zinc

17. A circuit diagram that represents the front and back door lights of a cabin wired in parallel is

18. The dimmest bulbs would be in circuit

19. In a light bulb, the tungsten filament functions as a

A. diodeB. resistorC. rheostatD. transistor

A circuit with one bulb and a 2-cell battery (produces 1.5 V for each cell) has a current of 20 amps running through it. What would be the resistance of the light bulb? (R = V/I)

_____ _____ _____ _____ ohms

4

Numerical Response

20. How much energy does a 100 w light bulb use in an hour? (E = P x t)

A. 100 JB. 360 kJC. 60 JD. 600 J

21. A diesel truck produces 47.5 kJ of useful output energy from 125 kJ of diesel fuel. What is the truck’s efficiency? (Ef = output/input x 100)

A. 17%B. 26%C. 38%D. 59%

22. A timing device for a race uses a laser unit that shines a beam of light across the finish line. As a competitor crosses the beam, the circuit is momentarily broken and the timing mechanism is activated. This timing device operates using a

A. gravitational electric processB. thermal electric processC. mechanical electric processD. photoelectric process

23. The device on an electric heater that controls how much electric current will flow through the electric heater, and therefore how much heat is produced, is called a

A. resistorB. switchC. variable resistorD. breaker switch

24. You have been given the task of creating the best possible “lightbulb” in the classroom by using different combination of materials. Your best choice of wire would be

A. as long and thin as possibleB. as long and thick as possibleC. as short and thin as possibleD. as short and thick as possible

Use this information to answer the next numerical response question.

Based on the information given, order the wires from lowest (1) to highest (4) resistance.

_______ _______ _______ _______ wire A wire B wire C wire D

25. To make a simple galvanometer to test low amperage, you would need

A. a compass and wireB. a magnet and wireC. a nail and wireD. a cell and wire

26. Fluorescent lights are to incandescent lights as wet cells are to __________.

A. electric circuitsB. rheostatsC. generatorsD. batteries

An engineer designed an electric circuit to test the heating effect of different thicknesses of the same type of wire. He kept the following variables the same: strength of current; length of wire; period of time. The table below shows the results.

Wire # Diameter (mm) Temperature (°C)ABCD

0.10.40.30.2

80506070

5

Numerical Response

27. Fuses and circuit breakers

A. increase the amount of current flow through a circuit B. shut off the current in an overloaded circuit C. control the direction of flow in a circuit D. turn on the current in an un-used circuit

28. Resistance within a conductor changes with temperature and the amount of the current running through the circuit. Which example given below would have the greatest resistance?

A. a light bulb filament with 10 A of current running through it at 5˚C B. a light bulb filament with 10 A of current running through it at 20˚C C. a light bulb filament with 20 A of current running through it at 5˚C D. a light bulb filament with 20 A of current running through it at 20˚C

Use this diagram to answer the next question.

29. The correct number of circuit subsystems would be

4

1

3

2

1 2 3 4A Conduct

orLoad Source Switch

B Switch Load Conductor

Source

C Source Switch Load Conductor

D Source Conductor

Switch Load

30. An electric heater draws 10 A from a 120 V source. What is the heater’s resistance?

A. 12.0 Ω B. 0.08 Ω C. 1200 Ω D. 130 Ω

Term # Term

1 Chemical Energy2 Electrical Energy3 Mechanical Energy4 Thermal Energy

There are many different forms of energy, and most can be converted from one form to another. For example, electrical

energy can be converted into thermal energy or mechanical energy, and chemical energy can be converted into electrical energy. Listed above are four different forms of energy.

Match the term number with the correct definition given below.

_____ the total kinetic energy of all particles in a substance _____ a form of potential energy released when reactants react _____ energy possessed by an object because of its motion _____ the energy of charged particles when electrons move

Use this diagram to answer the next question.

6

Numerical Response

Motor

Fuse

Bulb

fan

Garage door

31. Of the different loads on this circuit, which one would go out if the circuit overheated?

A. the light and fan B. the motorized garage door and fan C. only the light D. only the motorized garage door

Use this graph to answer the next question.

32. The conductivity of metals is affected by the temperature. The colder the metal, the better it conducts current. According to the graph shown above, the metal that would provide the most current in a circuit that would operate at 20°C would be

A. 1B. 2C. 3D. 4

Numerical Response

Electricity can be produced from a wide variety of sources. These include

1. thermal (heat) to electrical2. radiant (light) to electrical3. mechanical to electrical4. chemical to electrical

Match the number to the device that makes the energy conversion possible.

__________ __________ __________ __________ solar cell thermocouple battery generator

Use this information to answer the next question.

33. One type of electric drill is designed so that its motor speed can be changed. Which of the following diagrams represents the circuits of a drill of this type?

34. A science teacher asked the class to construct the best possible electromagnet using materials

7

found in the science lab. Of the combinations listed below, which would produce the strongest electromagnet?

A. a metal spike wrapped with 20 wraps of copper wire, with the wire connected to a 9-V battery

B. a metal spike wrapped with 20 wraps of nichrome wire, with the wire connected to a 9-V battery

C. a pencil wrapped with 20 wraps of copper wire, with the wire connected to a 9-V battery

D. a pencil wrapped with 20 wraps of nichrome wire, with the wire connected to a 9-V battery

35. Paul designs a new circuit for a light system for his private study chamber. Which diagram shows a circuit in which all three bulbs will light?

A.

B.

C.

D.