Brief-Constructed Response
Constructed Response
Title of Circuits
Concept
Electric
Teacher
Guide
Teacher
Guide
Students will need about 30 minutes to complete these constructed response tasks.
Objectives assessed:
• Understand the functions of common elements that make up series and parallel circuits and
interpret circuit diagrams.
• Understand that resistors in DC circuits increase in temperature because they dissipate
energy.
• Explain how the characteristics of transistors make them useful in electric circuits.
1. The symbols for some common elements that make up series and parallel circuits are shown
below.
Complete the table below.
• In the first column, fill in the names of the circuit elements.
• In the second column, draw in the corresponding symbols.
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Correct response(s):
Sample Correct Response:
Score
5
4
3
2
1
0
Content
Solution includes all correct table responses.
Solution includes at least ten correct table responses.
Solution includes at least eight correct table responses.
Solution includes at least six correct table responses.
Solution includes at least four correct table responses.
No response, or response not appropriate to the question.
Objectives assessed:
•
Predict the voltage or current in a simple DC circuit that includes wires, resistors, capacitors,
and batteries.
2. Consider the following circuit diagram:
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•
•
Draw the general shape of the graph of the current in the circuit over time.
Draw the general shape of the graph of the charge on the capacitor over time.
Correct response(s):
Sample Correct Response:
Score
3
2
1
0
Content
Both graphs show correct general exponential shape.
One graph shows correct general exponential shape.
Both graphs incorrect, but the student shows the basic understanding
that the first graph is decreasing and the second graph is increasing.
No response, or response not appropriate to the question.
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Objectives assessed:
• Use Ohm's law to describe the relationship between current, voltage, and resistance.
• Explain the relationship between electrical power, current, and voltage.
• Solve problems involving power in resistive circuit elements.
• For both series and parallel circuits, calculate the current, potential difference, resistance,
and power of different circuit elements.
• Design and build both series and parallel circuits.
3. A 12-V battery is connected in series with resistor R1 = 12 Ω and resistor R2 = 4.0 Ω.
•
•
•
•
•
Draw the circuit diagram and label it with each component.
Find the equivalent resistance.
Find the total current in the circuit.
Find the current through each resistor.
Find the power in each resistor and in the circuit.
Correct response(s):
Sample Correct Response:
[Art: Start with circuit diagram below, with 12 V battery at left, with 12 Ω and 4 Ω resistors in
series. We DO NOT own this art, so use the art below only as a starting point. Omit the
current arrow, use only two resistors, and make the battery look like the battery in the
diagram for Question 4. Also omit the green squiggly “E” label]
Req = R1 + R2 = 12 Ω + 4.0 Ω = 16 Ω
I=
12 V
V
=
= 0.75 A
Rtot 16 Ω
Pcircuit = IV = ( 0.75 A ) (12 V) = 9.0 W
V1 = IR1 = ( 0.75 A ) (12 Ω ) = 9.0 V
P1 = IV1 = ( 0.75 A ) ( 9.0 V ) = 6.75 W
( 0.75 A ) ( 4.0 Ω ) = 3.0 V
P2 = IV2 = ( 0.75 A ) ( 3.0 V ) = 2.25 W
V2 = IR2 =
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Score
4
3
2
1
0
Content
All of: draws correct circuit diagram; finds correct total resistance; finds
correct circuit current; finds correct power.
Three of: draws correct circuit diagram; finds correct total resistance;
finds correct circuit current; finds correct power. Allow points for correct
calculations using incorrect values found earlier.
Two of: draws correct circuit diagram; finds correct total resistance; finds
correct circuit current; finds correct power. Allow points for correct
calculations using incorrect values found earlier.
One of: draws correct circuit diagram; finds correct total resistance; finds
correct circuit current; finds correct power. Allow points for correct
calculations using incorrect values found earlier.
No response, or response not appropriate to the question.
4. A 12-V battery is connected in parallel with resistor R1 = 12 Ω and resistor R2 = 4.0 Ω.
•
•
•
•
•
Draw the circuit diagram and label it with each component.
Find the equivalent resistance.
Find the total current in the circuit.
Find the current through each resistor.
Find the power in the circuit.
Correct response(s):
Sample Correct Response:
1
1
1
1
=
+
=
Req 12 Ω 4.0 Ω 3.0 Ω
Req = 3.0 Ω
I=
12 V
V
=
= 4.0 A
Req 3.0 Ω
I1 =
V 12 V
=
= 1.0 A
R1 12 Ω
I2 =
V
12 V
=
= 3.0 A
R2 4.0 Ω
P = IV
= ( 4.0 A ) (12 V )
= 48 W
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Title of Concept
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Score
5
4
3
2
1
0
Content
All of: draws correct circuit diagram; finds correct equivalent resistance;
finds correct total circuit current; finds correct current through each
resistor; finds correct power.
Four of: draws correct circuit diagram; finds correct equivalent
resistance; finds correct total circuit current; finds correct current through
each resistor; finds correct power. Allow points for correct calculations
using incorrect values found earlier.
Three of: draws correct circuit diagram; finds correct equivalent
resistance; finds correct total circuit current; finds correct current through
each resistor; finds correct power. Allow points for correct calculations
using incorrect values found earlier.
Two of: draws correct circuit diagram; finds correct equivalent resistance;
finds correct total circuit current; finds correct current through each
resistor; finds correct power. Allow points for correct calculations using
incorrect values found earlier.
One of: draws correct circuit diagram; finds correct equivalent resistance;
finds correct total circuit current; finds correct current through each
resistor; finds correct power. Allow points for correct calculations using
incorrect values found earlier.
No response, or response not appropriate to the question.
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5. You have a 12 V battery, a R1 = 12 Ω resistor, and another component that requires a
current of 2.0 A and a voltage drop of 6.0 V. What value of resistor would you connect in
parallel with R1, with both resistors in series with the other component, to produce the
required current and voltage drop?
Correct response(s):
Sample Correct Response:
Voltage drop across resistors in parallel = 12 V – 6 V = 6 V
Equivalent resistance Req for parallel resistors:
6.0 V
Req =
= 3.0 Ω
2.0 A
1
1
1
=
+
Req 12 Ω R2
R2 =
R2 =
1
1
1
−
Req 12 Ω
1
1
1
−
3.0 Ω 12 Ω
R2 = 4.0 Ω
Score
3
2
1
0
Content
Calculates voltage drop across resistors, figures equivalent
resistance of parallel resistors, calculates R2.
Calculates voltage drop across resistors, figures equivalent
resistance of parallel resistors. Allow points for correct
calculations using incorrect values found earlier.
Calculates voltage drop across resistors. Allow points for
correct calculations using incorrect values found earlier.
No response, or response not appropriate to the question.
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6. You have a battery with leads B1 and B2, an open switch with ends S1 and S2, and two
resistors RA and RB with ends RA1 and RA2, and RB1 and RB2. Which ends would you
connect together to make a circuit with connected in parallel with the battery, and why do
you use the switch? Draw a picture of the circuit that would result.
Correct response(s):
Sample Correct Response:
[Art: Start with the circuit diagram given in the Correct Response to Question 4, and
omit voltage and resistance value labels. Add an open switch above and to the right
of the battery (i.e., above and to the left of the resistors), and label component ends
as discussed in the answer to Question 6. Component end labels will juxtapose at
connections between components. Place labels in close proximity to juxtapositions.]
Connect open switch end S1 to battery lead B1, ends RA1 and RB1 to S2, and ends RA2
and RB2 to B2. The switch is used for safety, so that electricity doesn’t flow in the
circuit until we activate it.
Score
3
2
1
0
Content
Draws correct circuit diagram, knows why open switch is used.
Draws correct circuit diagram, but does not answer about open
switch
Draws incorrect circuit diagram
No response, or response not appropriate to the question.
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