Science 9 Electricity Unit Test 2o11 KEY
Formulae:V = IR
E = Pt
P = IV
% Efficiency = output E / input E x 100
Section A: Multiple Choice - record answer on response sheet
1. After removing the laundry from the clothes dryer, you notice that two socks are sticking together. An explanation
for what has happened is
A.
protons have moved from one sock to the other, making one positively charged sock and one negatively
charged sock
*B.
one of the socks has gained electrons from the other sock, causing it to become negative while causing
the other sock to become positive
C.
both socks have gained protons and, as a result, are attracted to each other
D.
both socks have gained electrons and, as a result, are attracted to each other
2. Charge separation occurs when
*A.
charged objects are brought near neutral objects
B.
neutral objects gain static charges from charged objects
C.
objects with like charges are brought close to one another
D.
objects with opposite charges are brought close to one another
3. Your teacher explains to you that a glass of water is neutral. What does he mean by this?
A.
The water has no protons or electrons.
B.
The water is unaffected by static electricity.
*C.
The water has an equal number of protons and electrons.
D.
The water is not attracted to positively or negatively charged objects.
4. The unit used to measure how much electrical energy each charged particle carries in an electrical circuit is the
A.
ampere (A)
B.
watt (W)
C.
ohm (Ω)
*D.
volt (V)
5. In science class, you learned that a conductor is a material that passes electrons easily and that an insulator is a
material that does a poor job of conducting (or passing) electrons. How are the electrons in an insulator different
from the electrons in a conductor?
*A.
The electrons in an insulator are tightly bound to the positively charged nucleus.
B.
The electrons in an insulator are bound loosely to the positively charged nucleus.
C.
The electrons in an insulator flow toward the negative terminal.
D.
There are no electrons present in insulating materials.
Use the following information to answer the next 3 questions.
Hair dryers are a common household electrical device. Hair dryers draw their energy from a typical home electrical outlet.
This model has three different settings so that the fan can blow at different speeds and produce different levels of heat.
6. Using the hair dryer near water could result in a dangerous short circuit. This is because
A.
water will corrode and ruin the switch
*B.
water provides an alternative path for current to flow
C.
the fan is not meant to force water
D.
tap water cannot conduct electricity
7. What circuit component is likely responsible for the fan’s ability to turn at different speeds?
A.
switch
B.
cell
*C.
rheostat
D.
fuse
8. The blow dryer transforms electrical energy into what other forms of energy?
A.
chemical and mechanical
B.
chemical and thermal
*C.
thermal and mechanical
D.
mechanical and electrical
9. The rate at which charged particles flow is called
*A.
current
B.
voltage
C.
static
D.
potential difference
10. In an experiment you tested different aqueous solutions to determine which was the best conductor of electricity.
Of the solutions listed below, which one would be the worst conductor of electricity?
A. water collected from a melting glacier
B. water taken from the tap at OKCS
C. water taken from a mountain lake
*D. water from the ocean that has been distilled
11. You have learned that resistance in a wire changes with both the length and diameter of the wire. Which wire
would offer the most resistance to an electrical current?
A.
a wire that is 50 cm long and has a diameter of 3 mm
B.
a wire that is 25 cm long and has a diameter of 3 mm
*C.
a wire that is 50 cm long and has a diameter of 1.5 mm
D.
a wire that is 25 cm long and has a diameter of 1.5 mm
Use the following information to answer the next 2 questions.
A student purchases a new electric mixer for food preparation. This model has a single detachable mixing wand, and
plugs into a standard home electrical outlet.
12. To what part of the motor of the electric mixer do you attach the mixing wand?
A.
commutator
B.
wire
*C.
armature
D.
magnet
13. This mixer’s purpose is to perform what energy transformation?
*A.
electrical to mechanical
B.
chemical to thermal
C.
electrical to chemical
D.
electrical to thermal
14. Flowing water is often used as a model for voltage and current flowing through a wire. Which example would be
used to model a wire with the greatest voltage and current?
*A.
water flowing through a pipe with a 10-cm opening from a water tower 50 m above ground level
B.
water flowing through a pipe with a 10-cm opening from a fountain 1 m above the ground
C.
water flowing through a pipe with a 5-cm opening from a water tower 50 m above the ground
D.
water flowing through a pipe with a 5-cm opening from a fountain 1 m above ground level
Use the following information to answer the next 3 questions.
A student carefully analyzes a circuit and draws the following diagram:
Numerical Response
1. Match the circuit’s components with their labels by placing the appropriate letters in the spaces on the response
sheet.
cbda
15. Which of the following components in the circuit is a safety feature?
A.
component A
B.
component B
*C.
component C
D.
component D
16. The lamp in this circuit puts out approximately 112 J of light energy for every 2000 J of electrical energy put into it.
What is the efficiency of the lamp?
A.
17.9%
*B.
5.6%
C.
0.056%
D.
0.179%
Use the following information to answer the next 2 questions.
The following schematic represents a circuit built by a student.
17. The most obvious problem with the circuit is that
A.
the bulbs are connected in parallel
B.
C.
there is no switch
*D.
the bulbs are connected in series
the battery is connected improperly
18. The electrical source in this circuit is a battery not a single cell. This can be concluded because
A.
all circuits must be powered by a battery
B.
the battery is the largest circuit component
*C.
the schematic symbol indicates more than one cell
D.
there is always only one battery per circuit
Use the following information to answer the next 2 questions.
A student discovered that when the lamp burned out in this circuit, the motor would stop running.
19. When the lamp was replaced, the motor began operating again.
How could this problem be avoided in the future?
*A.
by connecting the motor and lamp in parallel
B.
by increasing the number of cells in the circuit
C.
by removing the switch from the circuit
D.
by connecting the motor and lamp in series
20. The device in the circuit that transforms chemical energy into electrical energy is the
*A.
battery
B.
lamp
C.
motor
D.
switch
21. While looking through a science catalogue, your teacher sees both ammeters and galvanometers in the section
advertising electrical measurement devices. Which situation would be best suited to using a galvanometer rather
than an ammeter?
*A.
measuring the amount of electrical current produced by a watch battery
B.
measuring the amount of electrical current produced by a 120-V outlet
C.
measuring the resistance of a high voltage power line
D.
measuring the resistance of a light bulb filament
22. Some resistors found in electronic devices consist of wire wrapped around an insulating core. Which of the
following would offer the least resistance?
A.
a long, thin wire wrapped around an insulating core
B.
a short, thin wire wrapped around an insulating core
C.
a long, thick wire wrapped around an insulating core
*D.
a short, thick wire wrapped around an insulating core
23. A ohmmeter is used to measure
A.
current
B.
*C.
resistance
D.
voltage
static charge
24. Which of the following devices uses the most energy?
A.
a 600-W microwave oven used for 20 minutes
*B.
a 100-W bulb left on for 8 hours
C.
a 1150-W hair dryer used for 8 minutes
D.
a 900-W hot plate used for 15 minutes
25. The most appropriate unit for reporting the amount of electrical energy used by a family every month would be the
A.
watt
B.
joule
*C.
kilowatt hour
D.
volt
26. Your teacher gives you a small electrical cell, which he has found in his desk drawer. He asks you to determine its
voltage by hooking it up to a voltmeter. When you connect the cell to the voltmeter, what is the expected reading
of the voltmeter in volts?
A.
0.0155 V
B.
0.155 V
*C.
1.55 V
D.
15.5 V
27. In an experiment carried out in science class, you were asked to determine what simple materials would be able
to produce an electric current. Which of the following combinations would result in an electric current being
produced?
A. two copper wires placed into a lemon 1 cm apart with a voltmeter connected between the two wires
B. two paper clips placed into a lemon 1 cm apart with a voltmeter connected between the two paper clips
*C. a paper clip and a copper wire placed into a lemon 1 cm apart with a voltmeter connected between the
copper wire and the paper clip
D. a paper clip and a copper wire hung on the edge of a glass filled with pure water 1 cm apart with a voltmeter
connected between the copper wire and the paper clip
28. While watching the news one night, you see a commercial for a new vehicle that will be powered by water. This
will be accomplished by passing electricity through water, producing pure oxygen and pure hydrogen. These two
gases will then be mixed together and ignited. This process of passing electricity through a substance to separate
molecules is called
A.
electrochemistry
B.
electrorefining
C.
electroplating
*D.
electrolysis
29. Victor owns a large grain farm in Alberta. It is important that the grain he harvests is dry when put into the
granaries for storage. The dryness of the grain can be determined by measuring the temperature of the grain. For
this task, Victor uses a thermocouple. What is a thermocouple?
A.
a device that can convert temperature into moisture content
B.
a device that can convert moisture content into electricity
C.
a device that can convert electricity into temperature
*D.
a device that can convert thermal energy into electricity
30. In order to construct a working electric motor, a permanent magnet and an electromagnet must interact. To keep
the motor spinning, the current passing through the electromagnet must change directions after each half turn.
The parts inside an electric motor that allow the current to change direction are the
A.
armature and brushes
*B.
commutator and brushes
C.
armature and commutator
D.
electromagnet and permanent magnet
31. Tracy is replacing the light bulb of a lamp in her family room. The power rating marked on the bulb is 60 W. This
means that the light bulb uses
A.
60 A/s
*B.
60 J/s
C.
60 Ω/s
D.
60 V/s
32. Which of the following would be most likely to approach 100% efficiency as an energy converter?
A.
an alkaline dry cell
B.
a halogen lamp
C.
a gasoline-electric hybrid vehicle
*D.
an electric heater
33. Which of the following would be classified as a renewable resource?
A.
coal
B.
oil
*C.
biomass
D.
natural gas
34. All functions of a computer, including the images on the screen and sound from the speakers, are controlled by
*A.
a binary code of prime numbers
B.
ultra-high electrical voltage
C.
laser pits on a surface of a disk
D.
intermittent random electrical signals
35. Solar cells are used to produce electricity for the International Space Station. Layers of what specially treated
substance are most commonly used in solar cells?
*A.
silicon
B.
copper
C.
glass
D.
aluminum
Use the following information to answer the next 3 questions.
In an evening of doing homework, a student uses the following four devices. The power, of each device is as follows:
 computer, 19.2 W
 stereo system, 800 W
 toaster oven, 1100 W
 coffee maker, 1600 W
36. If the computer draws 0.2 A of current, what voltage is being supplied to the computer?
A.
120 V
B.
484 V
*C.
96 V
D.
8.3 mV
37. Which of the following if “on” continuously, uses the most energy in a 24-hour period?
A.
the computer
B.
the stereo system
C.
the toaster oven
*D.
coffee maker
38. If the coffee maker is operated for 45 min, how much energy does it consume?
A.
4.32 J
*B.
4.32 MJ
C.
72 J
D.
72 MJ
Use the following information to answer the next 2 questions.
As student uses a 400-W electric chainsaw continuously during 100 minutes of cutting wood. The chainsaw is
approximately 40% efficient at converting energy.
39. The level of efficiency of the chainsaw is approximately 40%. In what form is
much of the energy lost?
A.
mechanical
B.
chemical
C.
electrical
*D.
thermal
40. Suppose during a day of wood cutting the chainsaw consumes 8.5 MJ of electrical energy. Considering the
efficiency of the chainsaw, how much useful output energy did the saw produce?
*A.
3.4 MJ
B.
0.21 MJ
C.
340 MJ
D.
8.5 MJ
41. Which of the following actions is least likely to be an example of energy conservation in Alberta?
A.
car-pooling with a friend to work
B.
switching all the incandescent bulbs in your home to compact fluorescent ones
*C.
switching from a gas-powered to an electric-powered car
D.
turning down the heat in your house
Numerical Response
2. The following energy transformation information was collected from a series of devices:
 A jet boat produces 128 kJ of mechanical energy from 1020 kJ of input chemical energy.
 An incandescent light produces 56 J of light energy from 850 J of input electrical energy.
 A luxury car produces 88 kJ of mechanical energy from 1000 kJ of input chemical energy.
 A motorbike produces 348 J of mechanical energy from 1220 J of input chemical energy.
Rank the devices from most to least efficient. Do this by placing the numbers 1 (most efficient) to 4 (least efficient) in the
spaces on the response sheet.
2431
42. Computers can write data to hard drives, compact discs, and other storage media. This information is stored as
A.
voltage
B.
current
C.
electrical pulses
*D.
binary numbers
43. Coal is considered a “fossil fuel” resource. How much electricity worldwide is generated by fossil fuel sources?
A
15%
B.
45%
*C.
65%
D.
85%
44. Hydro-electric plants are also found in Alberta. Which of the following do a coal-fired generating plant and hydroelectric power plant have in common?
*A.
turbine
B.
combustion chamber
C.
penstock
D.
high-pressure steam
Numerical Response
A group of students made a list of the characteristics of energy for a research project.
1.
Heat trapped from hot rock within Earth’s crust provides energy for electricity generation.
2.
Devices harness the energy released by atomic fission for use in electrical generation.
3.
Generating plants capture the energy of falling water.
4.
Biodegradable waste from landfill serves as the energy source. 2314
3.
Match the characteristics with the proper energy source. Record your answer on the response sheet.
45. Forests grow in many areas of Alberta. Trees are considered a renewable resource because
A.
they are easier to harvest than coal deposits
B.
they can be burned to produce energy
*C.
they can be regrown at the same rate they are used
D.
they do not produce pollution
46. Which of the following is NOT an environmental problem associated with coal-fired power plants?
A.
sulfur dioxide
B.
fly ash
*C.
flooding
D.
acid rain
47. When you turn on the fluorescent light in the laundry room, you notice one of the tubes is flickering and you
decide to replace it. You look in the storage room and find a new fluorescent tube. When you unwrap the new
fluorescent tube, you notice the following information on the packaging slip:



power consumption
energy input
energy output
- 34 W
- 12.5 kJ
- 2.75 kJ
The efficiency of the fluorescent tube is
A.
0.22
*B.
22%
C.
0.45
D.
45%
48. In Canada, all large household appliances must have an EnerGuide label. The purpose of this label is to indicate
A.
the voltage requirements of the appliance
B.
the current required to operate the appliance
*C.
the average monthly energy consumption of the appliance
D.
the amount of energy required in manufacturing the appliance
49. A new model of washing machine claims that it is more energy efficient because it washes more clothes with less
water. How can the manufacturer make this claim?
A.
The washing machine is smaller and therefore less energy is used to wash a load.
*B.
There is less water to heat and to pump; both of these processes require energy.
C.
The clothes come out drier with less water and drying requires less energy.
D.
The energy of the moving water is less because there is less water.
50. One of the greatest inefficiencies experienced in devices that convert electrical energy into mechanical energy is
due to the loss of energy through friction. One way to increase efficiency by reducing the amount of energy lost to
friction is to
*A.
apply a lubricant to moving parts
B.
reduce the input energy to moving parts
C.
slow down the moving parts
D.
speed up the moving parts
Science 9 Electricity Unit Test2o11
Name:
Multiple Choice:
ABCD
1. O O O O
2. O O O O
3. O O O O
4. O O O O
5. O O O O
6. O O O O
7. O O O O
8. O O O O
9. O O O O
10. O O O O
ABCD
11. O O O O
12. O O O O
13. O O O O
14. O O O O
15. O O O O
16. O O O O
17. O O O O
18. O O O O
19. O O O O
20. O O O O
ABCD
21. O O O O
22. O O O O
23. O O O O
24. O O O O
25. O O O O
26. O O O O
27. O O O O
28. O O O O
29. O O O O
30. O O O O
ABCD
31. O O O O
32. O O O O
33. O O O O
34. O O O O
35. O O O O
36. O O O O
37. O O O O
38. O O O O
39. O O O O
40. O O O O
ABCD
41. O O O O
42. O O O O
43. O O O O
44. O O O O
45. O O O O
46. O O O O
47. O O O O
48. O O O O
49. O O O O
50. O O O O
Numerical Response:
1.
_________
fuse
__________
resistor
__________
__________
light
battery
2.
_________
jet boat
__________
light
__________
luxury car
__________
nuclear
______________
hydro-electricity
__________
motorbike
3.
__________
geothermal
__________
biomass
Written Response:
Answer the following questions in the space provided
1.
List the four parts of an electric motor (in alphabetical order). What is the function of each part?
(4 marks)
a.
b.
c.
d.
2. Consider the following three charged objects. Objects A and B are fixed in position, but object C is free to move.
a)
b)
Will object C move? Explain your answer.
If you think object C will move, use an arrow to show its path of movement. Explain why you think object
C would take the path you have indicate
(3 marks)
3. Draw a diagram of a circuit that has a two-cell battery, two bulbs and a motor all connected in parallel. Add a switch
that allows you to turn off all three items at once. Another switch must also allow you to turn the motor off while the
light bulbs remain on. The complete circuit is protected by a fuse. (3 marks)
6. Describe how you would make or construct a wet cell. What basic parts would you need? How would you use them to
produce voltage? (3 marks)
7.
Describe one thing you could do in your own home to conserve energy. (1 mark)
Focus on Science and Technology
8.
Describe how technology can contribute to environmental damage. (3 marks)
Match each wet-cell component, as numbered above, with the names of the wet-cell and circuit components
below.
__________
__________
negative positive electrolyte
__________
load
__________
UNIT D—ELECTRICAL PRINCIPLES AND TECHNOLOGIES
Unit Test Answers
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
8.
__________
lamp
D
12.
B
13.
C
14.
C
15.
A
16.
C
17.
A
18.
D, A, B, C
C
20.
B
21.
D
C
A
A
A
B
C
D
19.
D
A
C
__________
__________
battery resistor fuse
__________
Unit Assessment