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American System Physics

A Physics Toolkit

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Representing Motion

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Accelerated Motion

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Forces in One Dimension

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Displacement and Force in Two Dimensions

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Motion in Two Dimensions

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Gravitation

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Rotational Motion

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Momentum and Its Conservation

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Energy and Its Conservation

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Thermal Energy

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States of Matter

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Vibrations and Waves

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Sound

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Fundamentals of Light

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Reflection and Refraction

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Interference and Diffraction

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Electrostatics

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Electric Current and Circuits

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Magnetic Fields

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Electromagnetic Induction and Electromagnetism

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Quantum Theory and the Atom

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Solid-State Electronics

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Quiz

19.1 Electric Current, Potential Difference and Power – Quiz

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Electric Current, Potential Difference and Power American Physics quiz: free practice for American System Physics. Work through this Electric Current, Potential Difference and Power American Physics quiz and get instant feedback on every answer. If you get stuck, review the 19.1 Electric Current, Potential Difference and Power — Notes lesson. More practice: American System Physics — all units. Syllabus: OpenStax free science textbooks.

  • Questions count: 50
  • Passing grade: A-
  • Time limit:
Start Quiz
1.
A current of 2.0 A flows in a wire for 4.0 s. How many electrons pass a point in the wire in this time? (Charge on one electron = 1.6 × 10⁻¹⁹ C.)
1.3 × 10⁻¹⁸ electrons
1.2 × 10¹⁹ electrons
5.0 × 10¹⁹ electrons
8.0 electrons
2.
A 60 W lamp is used for 5.0 hours every day for 30 days. Electricity costs 14 cents per kWh. What is the cost of running the lamp?
$1260
$1.26
$0.042
$12.60
3.
Each electron passing through a 12 V car headlamp transfers energy to the lamp. How much energy does one electron transfer? (e = 1.6 × 10⁻¹⁹ C)
1.9 × 10⁻¹⁸ J
12 J
1.3 × 10⁻²⁰ J
7.5 × 10¹⁹ J
4.
A 2.0 kW kettle and a 100 W laptop are each used for 30 minutes. How many times more energy does the kettle transfer?
2 times
20 times
200 times
The same energy, because the time is the same
5.
A student calculates the energy used by a 2.0 kW heater running for 3.0 hours as 6000 kWh. What error has the student made?
Used minutes instead of hours; the correct answer is 360 kWh
No error; 2000 × 3.0 = 6000 kWh
Used the power in watts instead of kilowatts; the correct answer is 6.0 kWh
Divided instead of multiplied; the correct answer is 0.67 kWh
6.
A phone charger supplies 5.0 V and a current of 2.0 A. How long does it take to transfer 18 000 J to the phone?
3.0 minutes
1800 minutes
180 minutes
30 minutes
7.
A student records readings for a lamp in the table. In which trial is the power of the lamp greatest?
Trial 3
Trial 1
Trial 2
Trial 4
8.
The table shows four household appliances and how long each is used in one day. Which appliance transfers the most energy that day?
Microwave
Water heater
Television
Refrigerator
9.
The electricity meter readings for a home are shown in the table. The price is 16 cents per kWh. What is the cost of the electricity used between the two readings?
$6720
$4.20
$67.20
$672
10.
A student measures the current at four points around a single series loop containing a cell and two lamps. She claims the results prove that current is used up by each lamp. Which is the best evaluation?
The claim is wrong; the readings differ only by about 0.01 A, within meter uncertainty, so the current is the same everywhere
The claim is correct because the reading after the lamps is smallest
The claim is correct because lamps convert current into light
The claim cannot be tested with ammeters
11.
A joulemeter records the energy supplied to a heater running at a constant current and p.d. Using the table, what is the power of the heater?
2880 W
48 W
0.021 W
96 W
12.
Using the table of quantities, which pairing of quantity, unit and meter is correct?
Current — coulomb — ammeter in series
Charge — ampere — ammeter in parallel
Potential difference — volt — voltmeter in parallel
Power — joule — voltmeter in series
13.
A student connects cells as described in the table. Which arrangement gives the largest e.m.f.?
Arrangement A
Arrangement B
Arrangement D
Arrangement C
14.
Two students each measure the current in the same lamp several times. Using the table, which statement is the best evaluation?
Student X is more precise (smaller spread); both have the same mean of 0.50 A
Student Y is more precise because the readings vary more
Student X must be more accurate because the readings are larger
Neither set is useful because the readings are not identical
15.
A student sets up the circuit shown to measure the current in the lamp. What is wrong with the circuit?
Dr Dabour Hub Academy - figure 1
The ammeter should be connected across the cell
The ammeter is connected in parallel with the lamp; it should be in series
Nothing is wrong; ammeters are always connected across a component
The switch must be removed for the ammeter to work
16.
The graph shows the charge that has passed through two wires, P and Q, against time. What is the current in wire P?
Dr Dabour Hub Academy - figure 2
20 A
2.0 A
0.50 A
0.20 A
17.
The graph shows the current from two supplies, X and Y. Which statement is correct?
Dr Dabour Hub Academy - figure 3
X is alternating current and Y is direct current
X is direct current and Y is alternating current
Both are direct current because both start at positive values
Both are alternating current
18.
The graph shows the current in a US household appliance. Using the time for one complete cycle, what is the frequency of the supply?
Dr Dabour Hub Academy - figure 4
50 Hz
60 Hz
120 Hz
17 Hz
19.
In the circuit shown, meters X and Y are both correctly connected. Which pairing is correct?
Dr Dabour Hub Academy - figure 5
X — voltmeter; Y — ammeter
X — ammeter; Y — ammeter
X — ammeter; Y — voltmeter
X — voltmeter; Y — voltmeter
20.
The graph shows the energy transferred by two appliances. What is the power of appliance A?
Dr Dabour Hub Academy - figure 6
2.0 W
2000 W
120 kW
33 W
21.
A heater is tested at a fixed p.d. and different currents; the graph of power against current is shown. What does the gradient tell you?
Dr Dabour Hub Academy - figure 7
The resistance of the heater, 12 Ω
The p.d. across the heater, 12 V
The energy transferred, 12 J
The charge flowing, 12 C
22.
What does it mean to say that the p.d. across a lamp is 6 V?
6 C of charge passes through the lamp each second
6 J of energy is transferred by the lamp each second
The lamp uses up 6 A of current
6 J of energy is transferred in the lamp for each coulomb that passes through it
23.
Which describes the difference between e.m.f. and p.d.?
e.m.f. is energy given to each coulomb by a source; p.d. is energy transferred from each coulomb in a component
e.m.f. is measured in joules and p.d. in volts
e.m.f. is measured in series and p.d. in parallel
There is no difference; both are the current in a circuit
24.
What is the charge carrier in a current flowing through a salt solution (an electrolyte)?
Free electrons only
Protons
Neutral atoms
Positive and negative ions
25.
A student states: "The battery supplies current, and the lamp uses it up to make light." Which improved statement is best?
The battery gives energy to the charges; the same current flows through the lamp, where energy is transferred to light and thermal energy
The battery supplies voltage, which flows through the lamp
The lamp uses up the charge, so less charge returns to the battery
The battery supplies electrons, which are destroyed in the lamp
26.
You are asked to plan an experiment to find the energy transferred by a lamp in 2 minutes. Which set of measurements is needed?
p.d. with an ammeter in series and time with a stopwatch
Current with an ammeter in series, p.d. with a voltmeter in parallel, and time with a stopwatch
Current with a voltmeter in parallel and temperature with a thermometer
Charge with a voltmeter and power with an ammeter
27.
Before taking readings, a student sees that the ammeter shows 0.02 A with the switch open. What should she do?
Nothing, because 0.02 A is small
Add 0.02 A to each reading
Zero the ammeter (or subtract 0.02 A from each reading) to remove the zero error
Connect the ammeter in parallel instead
28.
Why does the method tell you to open the switch between readings when measuring the current and p.d. of a lamp?
To let the cell recharge between readings
To make the ammeter more precise
To reverse the current direction
To stop the lamp and wires heating up, which would change the readings
29.
A charge of 450 C flows through a heater in 5.0 minutes. The current in the heater is _____.
90 A
1.5 A
0.011 A
2250 A
30.
A lamp connected to a 120 V supply carries a current of 0.50 A. Its power is _____.
240 W
60 W
0.0042 W
120 W
31.
Four 1.5 V cells are connected in series, all facing the same way. The e.m.f. of the battery is _____.
1.5 V
0.375 V
3.0 V
6.0 V
32.
Power is the rate of transfer of energy; one watt is equal to one _____.
joule per coulomb
coulomb per second
joule per second
volt per ampere
33.
A voltmeter is always connected in _____ with the component whose p.d. is being measured.
series
reverse
place of
parallel
34.
The table shows the total charge that has passed through a resistor at different times. The data show that the current was constant at 0.30 A. True or false?
False, because the charge keeps increasing
False, the current was 3.3 A
True only for the first 10 s
True
35.
In the graph, wire Q carries the larger current because its line is lower. True or false?
Dr Dabour Hub Academy - figure 8
True
True only after 20 s
False, because both carry the same current
False
36.
In the circuit shown, ammeter A1 reads 0.20 A. Ammeter A3 reads less than 0.20 A because the two lamps use up some of the current. True or false?
Dr Dabour Hub Academy - figure 9
False
True
True only if the lamps are lit brightly
False, A3 reads more than A1
37.
1 ampere is a current of 1 coulomb of charge passing a point each second. True or false?
True
False, 1 A is 1 joule per second
False, 1 A is 1 joule per coulomb
True only for alternating current
38.
Conventional current flows from the negative terminal of the supply, round the circuit, to the positive terminal. True or false?
True
False
True only in metal wires
True only for alternating current
39.
The volt is equivalent to a joule per coulomb. True or false?
False, it is a coulomb per second
False, it is a joule per second
True
True only for e.m.f., not p.d.
40.
An ideal ammeter has a very high resistance so that it does not affect the current. True or false?
True
True only for small currents
False, it has a resistance equal to the circuit
False
41.
The p.d. across a plain connecting wire in a working circuit is almost zero. True or false?
True
False, it equals the e.m.f.
False, it is always half the e.m.f.
True only when the switch is open
42.
If the current through a component doubles while the p.d. across it stays the same, the power transferred doubles. True or false?
False, it quadruples
True
False, it stays the same
False, it halves
43.
Mains electricity in the USA is alternating current at 120 V and 60 Hz. True or false?
False, it is direct current
False, it is 50 Hz
True
False, it is 230 V
44.
Charge can flow continuously only if there is a complete circuit. True or false?
False, a cell alone makes charge flow
True only for a.c.
False, charge flows as long as there is a voltmeter
True
45.
A 100 W lamp used for 10 hours transfers the same energy as a 1 kW heater used for 1 hour. True or false?
True
False, the lamp transfers 10 times more
False, the heater transfers 10 times more
False, the lamp transfers 1000 kWh
46.
A student says, "1 kWh = 1000 J." This statement is correct. True or false?
True
False
True only for heaters
False, 1 kWh = 3600 J
47.
Reversing one cell in a battery of three identical 1.5 V cells in series leaves an e.m.f. of 1.5 V. True or false?
False, it is still 4.5 V
False, it becomes 3.0 V
True
False, it becomes 0 V
48.
When recording the current with a digital ammeter, the positive (red) terminal should be connected towards the positive side of the cell. True or false?
False, it should face the negative side
False, the direction never matters for any meter
True only for voltmeters
True
49.
Electric charge is measured in coulombs and is a property of particles such as electrons and protons. True or false?
True
False, it is measured in amperes
False, only electrons have charge
False, charge is measured in volts
50.
A current of 3 A for 2 minutes moves more charge than a current of 5 A for 1 minute. True or false?
False, the 5 A current moves more
True
False, they move equal charge
True only if the p.d. is larger
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Part of Electric Current and Circuits — see every lesson and quiz in this unit.
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