WorksheetsScience 9 Unit D ELectrical Principles
Total questions: 76
Worksheet time: 56mins
What kind of electricity flows through circuits?
static electricity
current electricity
nuclear electricity
chemical electricity
Electricity is the movement of _____.
circuit
electrons
molecules
atoms
Which of the following statements best describes an electrical conductor?
does not allow electricity to pass through it
slows the flow of electricity through it
allows the flow of electricity through it
Which of the following is an insulator?
aluminum
iron
glass
copper
Like charges repel
A student is testing the conductivity of 4 different substances. He uses a 2.5 V battery and records the current in the circuit in each of the 4 substances. The chart below indicates the current measured.
Which substance is most likely an insulator?
Substance Q
Substance R
Substance S
Substance T
Which of the following changes to the cell shown above would result in voltage being produced?
Reversing the leads on the voltmeter
Using a greater volume of sulfuric acid
Replacing 5% sulfuric acid with 20% sulfuric acid
Changing one of the electrodes to a zinc electrode
How can it be explained that someone's hair can stick to a balloon?
There is static electricity.
There is too much dust in the air.
The person needs to wash his hair.
Opposite charges _______________.
attract
repel
nothing changes
Like charges _______________.
attract
repel
nothing changes
Facts About Electricity:
- Electrons can be discharged when clothes are removed from a clothes dryer.
- Electrons flow continuously through a conductor.
- Electricity can be used to operate a motor.
- Electricity can build up and produce lightning.
Which facts describe properties of static electricity?
1 and 2
1 and 4
2 and 3
2 and 4
Which of the diagrams above most accurately represents the charges in the wall when the balloon comes near the wall?
A
B
C
D
A
B
C
D
When electrons suddenly leave your body and enter a metal doorknob, it is called ...
A. electrocharging
B. electrical discharge
C. electrical charge up
D. charge separation
how does a fuse work?
A. the metal melts, and interrupts the current
B. the metal melts, and causes resistance
C. the metal increases the flow of electrons
D. the metal builds up electrons
If a 15A circuit breaker is replaced with a 20A breaker, it is
dangerous because ….
A. nothing would happen
B. less current will flow to the devices on the circuit
C. too much resistance will be added to the circuit
D. too much current could flow through the circuit and without the proper breaker, the circuit breaker would not disrupt the circuit and could potentially cause a house fire
A
B
C
D
the device used to measure voltage is
a thermometer
a fuse
amperes
a voltmeter
units for measuring current are
volts
amps
ohms
degrees
What is voltage?
the rate of flow of charge
the difference in charge between 2 points
the amount of available charge
What is a wet cell battery?
one that uses water to make electricity
one that uses a liquid electrolyte solution
one that uses a powdered electrolyte solution
What is a dry cell battery
one that uses water to make electricity
one that uses a liquid electrolyte solution
one that uses a paste electrolyte
The longer and thinner a wire, the more resistance it has.
True
False
Ohm's Law states
the resistance of a conductor changes
the current is proportional to the voltage
electrical energy is conserved
all of the above
The electricity in your household is
AC or alternating current
BC or basic current
CC or constant current
DC or direct current
In which circuit the bulbs will light up brighter?
X
Y
What is the type of this electrical circuit?
Parallel circuit
Series circuit
Which of the following affect the brightness of bulb? Tick the correct answers.
Type of circuit
Number of dry cell
Size of bulb
Number of bulb
Which bulb will light up the dimmest?
A
B
C
If bulb J is broken, what will happen to the other bulbs? Tick the correct answer.
bulb K lights up
bulb L lights up
bulb K and L do not light up
Power is measured in:
Watts
Joules
Amps
Volts
Power is measured in:
Watts
Joules
Amps
Volts
A bulb requires a voltage of 120V and has a current draw of 0.5A. What is the power rating of the bulb?
60W
240W
120W
1/2W
How much electrical energy is used when you have a 60W lightbulb on for 5 minutes?
18,000J
12J
1800J
300J
Which of the following is a renewable energy source?
Oil
Coal
Hydro
Nuclear
A device used to generate electricity by converting mechanical energy into electrical energy is called…
Motor
Generator
Light bulb
Conductor
A group of students built an electromagnet using a 9-volt battery, an iron nail and copper wire.
What can the students do to make the electromagnet stronger?
Increase the thickness of wire used.
Replace the iron nail with a smaller iron nail.
Decrease the number of turns in the wire coil.
Replace the battery with a higher voltage battery.
What parts of the motor function to provide a force to create the mechanical energy?
commutator and brushes
field magnets and armature
DC power source and terminals
What type of transformer is a location B?
step up
step down
What type of transformer is A?
Step up
Step down
What type of transformer is a location D?
step up
step down
What type of transformer is D?
Step up
Step down
If a transformer increases voltage, it is called a ......... transformer.
step right
step left
step up
step down
What will be observed when switch S1 is closed?
bulb A lights up
bulb B light up
bulb A and bulb B light up
bulb A and bulb B do not light up
Batteries are devices that change _______________ energy into _______________ energy.
chemical, thermal
thermal, electrical
chemical, electrical
electrical, mechanical
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)
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
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 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.
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 resistance represented by in the graph shown? (Use Ohm’s Law.)
3 Ω
0.33 Ω
1.2 Ω
0.83 Ω
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
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 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%
What effect does a hotter temperature have on resistance?
No effect
Increases resistance
Decreases resistance
Stays the same
Battery
Lines
Resistor
bulb
Consists of units wired in separate branches.
Which of the following is a disadvantage of hydroelectric power generation?
emits pollutants into the atmosphere
disrupts the natural flow of waterways
provides an unreliable method for producing energy
produces hazardous waste that requires long-term storage
