Download Electric Current Study Guide

Name: ___________________________________ Date: ____________________ Hour: _______
Physics A
Electric Current Study Guide
For this unit test, you should be using your notes as a resource, along with any other
classwork/homework/lab sheets completed over the last few weeks. In addition, your quizzes should
help you to identify your strengths and weaknesses for each of the learning targets that we covered.
As a reminder, the learning targets for the unit are attached on back page.
For each of the statements below, write whether the statement is true or false. If it is false, change
the statement to make it true.
Statement
a.
True or
False
Electrons are the mobile charge carriers in an electric circuit.
b. The location on an electric circuit where the charge possesses the greatest amount of
electric potential energy is the + terminal of the battery.
c. Charge is supplied with energy in the internal circuit and the energy is transformed
into other forms in the external circuit.
d. If a unit of charge has a high electric potential at any given location, then that charge
possesses a large amount of electric potential energy at that location.
e. A 6-Volt battery would provide 12 Joules of energy to 2 Coulombs of charge as it is
moved from the - to the + terminal.
f. Electric current is equal to the number of Coulombs of charge which move past a point
on a circuit per unit of time.
g. The electric current diminishes in value as charge progresses to locations further and
further from the + terminal of the battery.
h. Suppose a miniature light bulb is connected to a battery in a circuit. A light bulb with a
greater resistance will have a greater current.
i. The resistance of a conducting wire will increase as the length of the wire is increased
j. A 5-ohm resistor would allow a current of 0.5 Amperes when 2.5 Volts is impressed
across it.
k. Increasing the resistance of an electric circuit will cause the current in the circuit to
increase.
l. A miniature light bulb with a specific resistance is connected to a 1.5-Volt battery to
form a circuit. If it were connected to a 6-Volt battery instead, its resistance would
increase by a factor of 4.
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Name: ___________________________________ Date: ____________________ Hour: _______
Physics A
m. During any single loop of charge around a series circuit, the charge will pass through
each resistor in the circuit.
n. The total current in a circuit increases as more and more resistors are placed in series
in the circuit
o. The overall resistance of a circuit increases as more and more resistors are
placed in parallel in the circuit.
p. Suppose that three identical resistors with a resistance of 3-ohms are placed in
parallel with a 12-Volt battery. The current in the circuit is 1 Amp.
q. Power is the rate at which energy is used by an electric circuit.
r. A charge moving through an electric circuit would gain electric potential energy
in the internal circuit and lose electric potential energy in the external circuit.
Answer the following questions:
1) The potential energy possessed per unit of charge at any given location is referred to as the
electric ____________________________________.
Use the diagram to the right for questions 2 and 3
2) Place the letter A for an area where the electric potential is higher and B
where it is lower.
3) Use an arrow to indicate the direction of conventional current in the circuit and circle the area
where a voltage drop would occur.
4) Give at 3 roles of the battery in this circuit:
5) The charges that flow through the wires in your home ____.
a. are stored in the outlets at your home
b. are created when an appliance is turned on
c. originate at the power (energy) company
d. originate in the wires between your home and the power company
e. already exist in the wires at your home
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Name: ___________________________________ Date: ____________________ Hour: _______
Physics A
Use the diagram to the right to answer questions 6-9
6) At which point/s is the current at its highest amount? ______
7) The bulb between which two points to be the dullest? ________
8) List the letters in the correct order showing the direction of conventional current, starting at x.
________________________________
9) Redraw the diagram to show each of the 3 bulbs to be in a parallel circuit as opposed to in series.
Would anything change with the brightness of the bulbs?
10) Which of the following statements represent correct unit equivalencies? Circle all that apply.
a. 1 Ampere = 1 Coulomb / second b. 1 Watt = 1 Joule • second c. 1 Joule = 1 Volt / Coulomb
d. 1 Watt = 1 Volt • Coulomb / second
e. 1 Joule / Ohm = 1 Ampere • Coulomb
11) Draw a circuit showing two resistors in series and two resistors in parallel.
12) What is the voltage drop at resistor 2 if the R1 is 6 volts?
Us
e this for 12 & 13
13) If a third resistor (R3), identical to the other two, is added in series with the first two, then the
electric potential difference (voltage drop) across each of the three individual resistors will
________________________________
14) What would happen to the total resistance of this circuit is R3 was added in parallel?
15) If resistance remains constant, what happens to how will decreasing the voltage
affect the current?
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Name: ___________________________________ Date: ____________________ Hour: _______
Physics A
16) Three identical light bulbs are connected to a battery as shown at the right. Which adjustments
could be made to the circuit that would increase the current being measured at X? Circle all that
apply.
a. increase the resistance of one of the bulbs
b. decrease the resistance of two of the bulbs
c. increase the voltage of the battery
d. decrease the voltage of the battery
e. remove one of the bulbs
17) Consider the diagram below of a series circuit. For each resistor, use arrows to indicate the two
locations where one would have to tap with the leads of a voltmeter in order to measure the
voltage drop across the individual resistor. Finally, indicate the ammeter readings and the voltage
readings.
18) An attic fan at 140 watts is left on for 10 hours per day over a month time period (30 days). It is
plugged into a 120-volt outlet and the cost of electricity is $0.13 kW x hour. Calculate the energy
consumed and the cost for the month. (hint: 140 watts= .140 kW)
kW x hour is the unit of __________________________________
19) Give 4 examples of household energy conversions for items that use electrical energy in your
home every day.
20) Explain what a short circuit is and how a fuse works in such a circuit?
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Name: ___________________________________ Date: ____________________ Hour: _______
Physics A
Learning Targets
1. I can identify the requirements of an electric circuit.
2. I can identify circuit elements, such as power supplies, resistors, light bulbs, and switches, on a circuit diagram.
3. I can explain voltage and its function in a circuit.
4. I can calculate/rank/predict voltage in series and parallel circuits. 7/9
5. I can calculate the amount of work done when a charge moves through a potential difference, V.
6. I can explain current and its function in a circuit.
7. I can calculate/rank/predict current in series and parallel circuits. 8
8. I can explain resistance and its function in a circuit.
9. I can calculate/rank/predict resistance in series and parallel circuits.
10. I can use Ohm’s Law to explain the relationships between current, voltage & resistance.
11. I can explain the difference between complete circuits, open circuits, and short circuits.
12. I can explain energy transfer in a circuit.
13. I can explain the difference between electric power and electric energy.
14. I can predict and calculate power in a circuit.
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