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WorksheetsElectricity Unit Review
Total questions: 116
Worksheet time: 58mins
How can an object become positively charged?
gain electrons
gain protons
lose electrons
lose protons
Kamal walked across a carpet on a dry winter day. The results are illustrated in this drawing. What happened to Kamal’s shoes and the carpet?
Both the shoes and the carpet lost electrons.
The shoes gained electrons and the carpet lost electrons.
Both the shoes and the carpet gained electrons.
The shoes lost electrons and the carpet gained electrons.
Which of the following statements about the ‘Law of Charges” is not true?
All matter is neutral.
Unlike charges attract.
Charged objects attract neutral objects.
Like charges repel.
If the two charges represented in the figure were brought near each other, they would
attract each other
repel each other
cause static discharge
have no effect on each other
In science class, your teacher rubs a glass rod with a piece of rabbit fur and moves the glass rod toward a suspended piece of vinyl. The piece of vinyl moves toward the glass rod. The reason this happens is…
the glass rod and the piece of vinyl have opposite charges
the glass rod and the piece of vinyl have like charges
the glass rod and the piece of vinyl have a combined neutral charge
the glass rod has become charged, which attracts the neutral vinyl
Charge separation occurs when…
charged objects are brought near neutral objects
neutral objects gain static charges from charged objects
objects with like charges are brought close to one another
objects with opposite charges are brought close to one another
Sandra, being quite tired and still sluggish with sleep, drags her feet across the carpet as she walks toward the bathroom. When she touches the metal doorknob, she receives an electric shock. Why?
She has generated in the door an excess of charges and the charges are released when she touches the doorknob.
She has generated in her body an excess of charges, which are then transferred to the doorknob when she touches it since metal is a good insulator.
She has generated in her body an excess of charges, which are then transferred to the metal doorknob when she touches it since metal is a good conductor.
She has generated in the door an excess of charges and the charges are released when she touches the doorknob since she is a good insulator.
The type of energy that Sandra has just experienced is called _______________ _______________.
current electricity
static electricity
unbalanced electricity
friction energy
Later in the morning, Sandra is getting dressed. She notices that when she pulls her sweater over her head, she sees little sparks between her sweater and her t-shirt. What are the sparks?
They are atoms moving from her sweater to her t-shirt.
They are protons that are moving between her sweater and her t-shirt.
They are electrons that are moving between her sweater and her t-shirt.
They are neutrons that are moving between her t-shirt and her sweater.
Sandra knows that the small sparks are nothing to be concerned about since they are just small transfers of electrical energy called electrical _______________.
discharge
charge separation
polarization
current
The diagram shows an unsafe use of an extension cable. What is the electrical hazard?
The cables may get overheated.
The appliances connected will burn out.
There is a loose connection.
The fuse will burn out.
Which of the following is an important safety device found in most new homes to prevent possible fires due to overheated electrical wires?
transformer
transistor
fuse box
circuit breaker
A fuse is a device that is used to increase the safety of an electrical system. How does a fuse work?
A fuse has a metal strip that can be replaced after melting when too much electricity passes through the fuse.
A fuse has a spring mechanism that turns off a switch when too much electricity passes through the fuse.
A fuse has a thin metal strip inside, which melts when too much electricity passes through the fuse.
A fuse will only allow a certain amount of electricity through it and must be replaced before it burns out.
If too much power is drawn from the top circuit in the diagram, what may happen to the circuits in the house?
The main circuit breaker would open, stopping all current in the house.
Only the circuit breaker for that top circuit would open, affecting the appliances and outlets on that one circuit.
The circuit breaker for the top circuit and all other circuit breakers in other circuits in the house would also open, stopping the flow of current, but the main circuit breaker would stay intact.
The wires leading into the main circuit breaker would get hot enough to possibly start a fire.
One day your class goes on a field trip out to the country and you notice that several barns have a tall metal pole on the top. When you ask your teacher what they are, she tells you that they are called lightning rods. The purpose of a lightning rod is to…
provide a path for the static electricity of lightning to pass harmlessly into the ground
prevent lightning from striking near the farm by emitting a negative electric charge
collect any electricity produced by lightning and convert it into usable electricity
warn the farmer that lightning is in the area so the farmer can prepare
Match the following types of circuits.
(a)
Rachel was reading a pamphlet on electric safety. Which one of the following is not a good electric safety tip that Rachel might see in a pamphlet?
Do not overload an outlet or circuit by plugging in too many electric devices at once.
Replace worn or frayed electrical cords to reduce the risk of electric shock.
Do not use electric devices near water or outside in the rain.
Use only ungrounded or two prong electrical cords outside.
What is the difference between a conductor and an insulator?
An insulator allows electricity to flow through it easily and a conductor does not.
A conductor allows electricity to flow through it easily and an insulator does not.
An insulator is magnetic and a conductor is not.
A conductor is magnetic and an insulator is not.
A good conductor
Has many free electrons
Has few free electrons
Has many free protons
Has few free protons
The plastic covering on the wire is there to:
Provide a conductor for electrical energy to flow.
Provide an insulator so that electrical energy will not pass outside of the wires.
Provide a conductor so that electrical energy can NOT flow.
Provide an insulator so that electrical energy can flow.
Batteries are devices that change _______________ energy into _______________ energy.
chemical, thermal
thermal, electrical
chemical, electrical
electrical, mechanical
Match the following parts of an electrochemical cell.
(a)
Which set-up will provide the largest voltage?
Which electrolyte will produce the largest voltage in an electrochemical cell?
Distilled water
5% vinegar solution
10% vinegar solution
15% sugar solution
One of the circuit diagrams in her book on electricity calls for the use of a cell to provide energy for the circuit. What is the difference between a cell and a battery?
A cell is a combination of batteries
A battery is a combination of cells.
A battery provides less energy than a cell.
A cell provides energy only when it is connected to other cells, not so with batteries.
The amount of electric charge flowing through the wire is called its
Current
Voltage
Power
Resistance
Match the following
1 - unit which resistance is measured in
2 - abbreviation for current used in Ohm’s Law
3 - units which potential difference is measured in
4 - units which current is measured in
(a)
Janet heard her father calling her out to help with some yard work. When she got outside, she saw her dad struggling with attaching a sprinkler to a garden hose. Immediately, Janet made a mental connection between electric circuits and the water hose and sprinkler. Match the electrical components to the corresponding letters for the parts of the hose and sprinkler arrangement.
1 sprinkler head
2 the garden hose
3 the valve on the side of the house
4 the water
(a)
The unit used to measure how much electrical energy each charged particle is given in an electrical circuit is the…
ampere (A)
watt (W)
joule (J)
Volts (V)
Jerry pushes a shopping cart through the grocery store for his mother. Using this analogy for current, voltage, and resistance, which of the following statements is most appropriate?
the force Jerry pushes with = voltage; the movement of the cart = current; friction = resistance
the force Jerry pushes with = current; the movement of the cart = voltage; friction = resistance
the force Jerry pushes with = voltage; the movement of the cart = resistance; friction = current
the force Jerry pushes with = current; the movement of the cart = resistance; friction = voltage
Which of the following will cause an increase in the resistance of a wire?
Shorten the length of the wire.
Increase the diameter of the wire.
Increase the length of the wire.
Change the type of wire to one that is a better conductor.
Neil wants to determine the voltage passing through a circuit composed of a battery and a length of wire. The problem is that he does not have a voltmeter. He does, however, have an ammeter. Neil also knows that the wire has a resistance of 25 Ω. When Neil connects the ammeter to the circuit he records a current of 10A. What is the voltage passing through the circuit?
250 V
2.5 V
0.4 V
35 V
A circuit has a 24 volt battery and the resistor is 8 ohms. How much current is running through the circuit?
192 A
3 A
0.33 Ω
3 Ω
What resistance is needed to cause a 20A current flow because of a 100V battery?
0.2 Ω
2000 Ω
120 Ω
5 Ω
If an electric toaster runs off of a 120V wall outlet and has a current of 10.5 A running through it, what is the resistance in ohms in the toaster? Round your answer to the tenths place.
(a)
A 220 Ω resistor is connected in series with a 9 V battery in a circuit. According to Ohm’s Law, what will happen to the circuit if another 220 Ω resistor is added in series?
Total current will decrease.
Total current will increase.
Total voltage will decrease.
Total voltage will increase.
What is resistance represented by in the graph shown? (Use Ohm’s Law.)
3 Ω
0.33 Ω
1.2 Ω
0.83 Ω
Some resistors found in electronic devices consist of wire wrapped around an insulating core. Which of the following would offer the least resistance?
A long, thin wire wrapped around an insulating core.
A short, thin wire wrapped around an insulating core.
A long, thick wire wrapped around an insulating core.
A short, thick wire wrapped around an insulating core.
In the figure shown to the right, what is the load?
the wires connecting the light to the battery
the light bulb
the battery
no load in this figure
Which circuit diagram symbol would be a source of potential difference for a circuit?
Match the following parts of a circuits
1 –conductor
2 – load
3 – source
4 – switch
(a)
The diagram shows a _______________ that is used to control the amount of current or voltage through a circuit. The resistance may be changed according to the requirements of the circuit.
rheostat
ammeter
ohmmeter
breaker
Depending on the purpose of an electrical device, a switch or a variable resistor might be included in the design of the device. For each device below, decide whether a switch or a variable resistor would best serve the function of the device.
1 = switch
2 = variable resistor
(a)
In the circuit diagram shown on the right, the source is a …
battery consisting of 3 cells
battery consisting of 6 cells
cell consisting of 3 batteries
cell consisting of 6 batteries
When shopping for a set of Christmas lights, you see the picture to the right on the package. This is a diagram of…
a closed parallel circuit
a closed series circuit
an open parallel circuit
an open series circuit
While on a field trip to the Alberta Legislature you see a beautiful chandelier hanging in the main hallway. You notice that one of the light bulbs is burnt out yet the remaining bulbs continue to burn. This is possible because…
the bulbs on the chandelier each have a different electrical source
the bulb that is burnt out is still able to conduct electricity
the bulbs on the chandelier are set up on a parallel circuit
the bulbs on the chandelier are set up on a series circuit
Why do households use parallel rather than series circuits?
Series circuits are more complicated, so parallel circuits are used.
There is not enough electric power going into most houses to operate series circuits.
Households have several appliances that need to operate independently of each other.
Series circuits require more wires and are, therefore, more expensive.
Electrical circuits can be set up as either parallel circuits or as series circuits. For each example given below, identify whether it is a parallel circuit or a series circuit.
1 = parallel circuit
2 = series circuit
(a)
The traffic diagram to the right is most similar to a _______________ circuit.
series
parallel
branch
multiple
One of the characteristics of the type of circuit in the previous question is that it has several _______________, or paths.
branches
currents
resistors
series
Which circuit will have the highest current reading when the switch is closed?
Daniel sets up a circuit with two batteries, 3 light bulbs, X, Y and Z and some wires. One of the light bulbs, X, is broken. When he sets up the electric circuit as shown, which of the bulb(s) will remain lit?
Bulb Y only
Bulb Z only
Bulb Y and Bulb Z only
None of the bulbs
The diagram shows an electric circuit. Which switch(es) must be closed so that only Bulb A and Bulb B light up?
Switch 3 only
Switches 1 and 2 only
Switches 1 and 3 only
Switches 1, 2 and 3
Elaine sets up two circuits as shown. All the bulbs and dry cells in the two circuits are identical and in good working condition. If Elaine connects another dry cell across XY, what are the likely observations that she will make?
I - The bulb in Circuit P will be brighter than before.
II - The bulbs in Circuit Q will be dimmer than before.
III - The bulbs in Circuit Q will be brighter than before.
IV - The bulb in Circuit P will last longer than those in Circuit Q.
I and II only
I and III only
I and IV only
II and IV only
What happens when the middle bulb burns out in the circuit shown?
All bulbs go out.
Only the first stays on.
The remaining bulbs stay on.
Only the last stays on.
The picture shows an electrical circuit. This circuit is a series circuit because:
It has 3 light bulbs.
The same current flows through all three light bulbs.
It uses a single battery.
The electrical current is divided between the three light bulbs.
In which circuit will the bulbs be the brightest and why?
Circuit A, because series circuits have a single path and offer the least resistance.
Circuit B, because series circuits have a single path and offer the least resistance
Circuit A, because parallel circuits have multiple paths and offer the least resistance.
Circuit B, because parallel circuits have multiple paths and offer the least resistance.
In Circuit A, what will happen if bulb B burns out?
Both bulb A and bulb C will go out.
Bulb A will stay lit, but bulb C will go out.
Bulb A and bulb C will stay lit.
Bulb A will go out, but bulb C will stay lit.
In Circuit B, what will happen if bulb F burns out?
Both bulb D and bulb E will go out.
Bulb D will stay lit, but bulb E will go out
Both bulb D and bulb E will stay lit.
Bulb E will go out, but bulb E will stay lit.
Which bulbs are connected in parallel with each other?
A and C
B and D
A and D
C and D
What would NOT be an important controlled variable in the experiment with Circuit A?
Number of bulbs
Number of batteries
Type of bulbs
Type of wire
Based on the graphs above, which one of the following statements would be true?
No bulbs will remain lit when more bulbs are added to Circuit B.
The bulbs in circuit A must be connected to stronger batteries
Adding more bulbs in circuit A increases the resistance in the circuit
The rest of the bulbs would remain lit when one of the bulbs in Circuit A is blown
What can you use to make an electromagnet?
Battery, nail and string
Battery, pencil and wire
Wire, battery and iron ore (nail)
Peanut butter, lampshade, hand sanitizer
How are electromagnets different from magnets?
permanent magnets can be turned on/off
you can turn an electromagnet on/off
magnets are more powerful
magnets have a North and South pole
Which of the following will increase the strength of an electromagnet?
Use a smaller voltage battery.
Use a plastic core.
Use more wraps of wire around the core.
Use more unwrapped wire between the battery and the electromagnet.
What benefit is gained by the addition of the iron core in an electromagnet?
It makes a strong magnet weaker.
It makes a weak magnet stronger.
There is no benefit at all.
It lets currents interact with each other.
The device shown is a(n)
Motor
Generator
Electromagnet
fan
Which of the following choices correctly labels the three parts?
A - split-ring; B: brush; Commutator
A - brush; B - coil; C - armature
A - armature; B - split ring; C - coil
A - brush; B - split ring; C - coil
What is the function of part B?
Provides a current to the system.
Repels and attracts the permanent magnet.
Increases the magnetic field.
Alternates current so the motor continues spinning.
If an additional 1.5 V cell was added to the circuit, the motor would ____________.
stop spinning
change direction
spin faster
spin slower
Adam wants to fix a faulty electric motor. He screws open the cover and finds the following arrangement of parts. What is wrong with the motor?
The force does not rotate the coil.
The magnets are arranged wrongly.
There are no brushes.
There is no split ring commutator.
What is the energy transformation in a motor?
chemical to mechanical
electrical to mechanical
mechanical to electrical
physical to potential
An electric motor contains a(n) ________that rotates between the poles of a magnet.
electromagnet
generator
Cell or battery
circuit
An electric motor converts electrical energy into mechanical energy. This mechanical energy is in the form of a rotating coil inside the motor. What is the proper term for the part that rotates inside the motor?
Armature
Brushes
Commutator
Transformer
In large generators in power plants, ___________ rotate inside a coil of wire to produce an electric current.
wind
water
magnets
circuits
What is the fan shaped blade that turns the magnet inside a generator called?
electromagnet
turbine
solar panel
pinstock
What type of energy comes OUT of a generator?
Mechanical
Electrical
Thermal
Potential
This type of transformer goes from having lower voltage to having higher voltage.
A step-up transformer
A step-down transformer
An up-down transformer
A block transformer
What kind of transformer will you find at point 2?
A step-up transformer
A step-down transformer
An up-down transformer
A block transformer
What is the purpose of a step-up transformer at an electrical generating station?
Increasing the power of the electricity.
Allows for safer transmission of low voltage electricity.
Allows for efficient transmission of high voltage electricity.
Decreases the power generated to a safe level.
Which one of the following best shows the correct energy conversion which occurs in the street lamp?
solar energy ----> light energy + heat energy
solar energy ----> electrical energy ----> light energy
chemical potential energy ----> electrical energy ----> light energy
electrical energy ----> light energy ----> chemical potential energy
Maria and her mother decide to bake some chocolate chip cookies. Maria’s mother asks her to preheat the electric oven by turning it on. When Maria looks inside the oven she sees the element glowing a bright orange and when she touches the door she can feel the heat. What is happening?
Chemical energy is being converted into thermal energy, some of which is then converted into thermal energy.
Chemical energy is being converted into thermal energy, some of which is then converted into light energy.
Electrical energy is being converted into light energy, some of which is then converted into thermal energy.
Electrical energy is being converted into thermal energy, some of which is then converted into light energy.
Ms. J's students are complaining that it is hot in the classroom. She plugs in the fan and turns it on. Which energy transformation occurs?
mechanical to electrical
electrical to mechanical
chemical to mechanical
electromagnetic to mechanical
Which one of the following shows the correct headings for P, Q, R and S?
P = Potential energy, Q = Electrical energy, R = Mechanical Energy, S = Light energy
P = Heat energy, Q = Electrical energy, R = Sound Energy, S = Heat energy
P = Potential energy, Q = Sound energy, R = Electrical Energy, S = Light energy
P = Heat energy, Q = Sound energy, R = Mechanical Energy, S = Light energy
As water flows through a dam, a generator is turned and creates enough electricity for thousands of homes. This describes...
biofuels
hydroelectric energy
geothermal energy
solar energy
In the diagram of the hydroelectric dam shown, which structure does the label Y represent?
motor
transformer
generator
turbine
Electricity is produced by using steam to _____________.
heat the turbine generators
spin the turbine generators
reduce friction in the turbine generators
reduce emissions from the turbine generators
Electrical energy throughout the world is produced in vast amounts and in various ways. Worldwide, the majority of electrical energy is produced by…
the movement of water through hydro-electric generators
the collection of geothermal energy from the Earth
the burning of fossil fuels such as coal, oil and natural gas
the splitting of atoms through the process of nuclear fission
One alternative to burning fossil fuels as a source of energy for electricity-generating plants is to burn the gases produced from decomposing biodegradable waste. Decomposing biodegradable garbage including grass clippings and food-based garbage is referred to as…
biochemical waste
hydroelectric power
biological magnification
biomass
Which of the following matches stage 1?
turn generator
heat water
burn fuel
move turbine
Windmills can be connected together in what are called “wind farms” to generate electricity. What energy conversion(s) occur that allow the air particles of wind to produce electricity?
thermal energy to electrical energy
chemical energy to electrical energy
mechanical energy to electrical energy
mechanical energy to thermal energy to electrical energy
A community depends on wood from the surrounding forests for home heating and for heating the boiler for the community’s electricity generator. The community’s plan is to replace the trees that they harvest with new trees to ensure that the population of trees is maintained indefinitely for future generations. This practice of maintaining a resource indefinitely is called…
resource conservation
resource maintenance
resource protection
resource sustainability
Your science teacher leads a discussion concerning the societal effects of energy consumption. She suggests that, as a society, we must make decisions to conserve energy. Which of the following would clearly be an example of a societal decision to save energy?
Vladimir replaces his gasoline-powered car with an electric car.
A city decides to install low wattage street lamps to reduce energy use.
Sue and her mom wash dishes together and use the time as a chance to talk.
A corporation decided to install more powerful computers.
Both renewable and non-renewable resources can be used in the production of electrical energy. Listed below are four different energy sources that are used in the production of electricity. For each example given below, identify whether it is a renewable or non-renewable energy source.
1 = renewable
2 = non-renewable
(a)
How much power is required to run a computer if a current of 4.5 A passes through it when connected to a 110V wall outlet?
495 W
24 W
0.04 W
250 W
How much electrical energy is consumed by a 100 W light bulb if it is left on for 1.5 h (5400s)?
540 J
150 J
540 000 J
54 J
A 1200 W hot plate is used continuously for 20.0 min. How much electrical energy in kWh does the hotplate use in this time?
0.4 kWh
60 kWh
24 000 kWh
24 kWh
Kilowatt - hour is the unit of ______________.
potential difference
electric power
electrical energy
charge
If a unit of electricity (1kWh) costs 15 cents, how much will it cost to run a 2 kW electric heater for 3 hours?
6 cents
90 cents
75 cents
20 cents
Your gaming system runs on 120V and is pulling 3A. How much power are you using?
50 Ω
360 V
360 W
40 W
A 240W light bulb is running at 120V. What is the current?
0.5 A
5 V
2 A
2 V
CHALLENGE: A heating element resistance is 24 ohms. The current measures 10 Amps. What is the power?
240 W
1200 W
1000 W
2400 W
You read that your hairdryer has a power rating of 1600 W and a voltage rating of 125 V. What is the current, in amperes (A), passing through the hairdryer?
12.8 A
0.078 A
200 A
78.1 A
If an electric water heater uses 30 kW of power and runs for 6 hours, what is the total amount of energy used?
5 kilowatt-hours
36 kilowatt-hours
180 kilowatt-hours
360 kilowatt-hours
A vacuum cleaner is labelled "230 V, 1200 W". Which of the following statements is true?
The vacuum cleaner uses 230 V of energy.
The vacuum cleaner has a power of 5.22 A.
The vacuum cleaner has a working current of 0.192 A.
The vacuum cleaner uses 1200 J of energy every second.
When shopping for a new desk lamp, Patrick must decide between a lamp that uses an incandescent light bulb or one that uses a fluorescent tube. The salesperson tells Patrick that the drawback of the lamp with the incandescent light bulb is that it is very inefficient. What does the salesperson mean by inefficient?
The light bulb does a poor job of converting input energy into the desired output energy.
The light bulb is expensive considering its expected life span under normal conditions.
The light bulb will need to be replaced often because it contains a filament with high resistance.
The light bulb does not produce sufficient light regardless of the amount of electricity being used.
The law of conservation of energy states that when one form of energy is converted into another,
energy is destroyed in the process.
no energy is destroyed in the process.
energy is created in the process.
some amount of energy cannot be accounted for.
A light bulb converts 100J of electrical energy into 40J of light energy. What is its efficiency as a percentage?
140%
60%
40%
250%
A battery converts 5000J of chemical energy into 3000J of electrical energy. What is its efficiency as a percentage?
60%
80%
20%
40%
According to his findings, Jason determined that the most efficient engine is the…
gasoline engine
gasoline-electric hybrid engine
natural gas engine
diesel engine
Which of the following devices would most likely have the highest efficiency?
pump
heater
motor
light
CHALLENGE: Rachel wanted to calculate the efficiency of a particular brand of coffee maker. Given the following information from the salesperson, how efficient was the coffee maker? "The 1200 W coffee maker takes 5 min to make a pot of coffee. It took 250 000 J of energy to heat the water to the correct temperature."
It is about 69% efficient.
It is about 75% efficient.
It is about 60% efficient.
It is about 31% efficient.
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…
apply a lubricant to moving parts
reduce the input energy to moving parts
slow down the moving parts
speed up the moving parts
What was the manipulated variable in the experiment?
Number of switches
Type of material (X, Y, Z, W)
Brightness of the light bulb
Voltage source
Which of the four materials would be most suitable for safely covering over bare electrical wires to prevent shocks and short circuits?
X
Y
Z
W
Statement 1 relates to which of the following perspectives?
Educational
Environmental
Ethical
Economic
