Worksheet: Circuits and Ohm

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Chapter 35 Worksheet Circuits and Ohms Law
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EQUATIONS
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ELECTRICAL CIRCUIT SYMBOLS
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1. Draw a circuit schematic (diagram) to include
a 50.0 V battery, an ammeter, and a resistance
of 10.0 O in series.
A
-
50.0 V
10.0 O
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a. What is the reading on the ammeter?
A
-
50.0 V
10.0 O
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b. In which direction is the current flowing?
Conventional current ()
A
-
50.0 V
10.0 O
Electron flow (-)
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2. How much current flows through a radio speaker
that has a resistance of 4.0 O when 16 V is
impressed across the speaker?
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Draw a circuit diagram of the circuit described
in the question above. Include a 6 V battery, an
ammeter (labeled with value of current), and a
resistance of 3.0 O (the speaker). Also label
the direction of the conventional () current.
2 A
Conventional current
A
-
6 V
3.0 O
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4. The following questions pertain to the circuit
diagramed to the right. a. Lamp A reads a voltage
of 12 V. What is the voltage of lamp B?
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4. The following questions pertain to the circuit
diagramed to the right. a. Lamp A reads a voltage
of 12 V. What is the voltage of lamp B?
Since this is a parallel circuit, the voltage in
each branch of the circuit is equal to the
voltage source. Therefore, Voltage is equal to
12 volts in each lamp
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b. If the ammeters on both branches read the same
amount, what does this tell you about the
resistance of the two branches?
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b. If the ammeters on both branches read the same
amount, what does this tell you about the
resistance of the two branches?
Since this is parallel circuit, the resistance in
each branch can be calculated with the following
equation Since the voltage and current are the
same in each branch, the resistance will be the
same
Rearrange and get
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c. If the current flowing in the first branch was
4.0 A and 6.0 A in the second branch, what would
the total current in the circuit be?
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c. If the current flowing in the first branch was
4.0 A and 6.0 A in the second branch, what would
the total current in the circuit be?
Total current in a parallel circuit can be
calculated with the following equation
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5. Draw a series circuit diagram showing a 6.0 V
battery, a resistor, an ammeter reading of 2.0
A.
2.0 A
A
6.0 V
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a. Label the size of the resistor, the direction
of conventional current, the () and (-)
terminals of the battery.
2.0 A
A
6.0 V
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a. Label the size of the resistor, the direction
of conventional current, the () and (-)
terminals of the battery.
2.0 A
Conventional current
A
-
6.0 V
3 O
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b. Add a voltmeter to you diagram and indicate
the potential difference across the resistor.
2.0 A
A
6.0 V
6.0 V
V
Therefore Vs V1 6.0 V
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6. Draw a circuit diagram showing a heater with a
resistance of 6 O, and a potential difference
source of 24.0 V.

A
24.0 V

V
6O
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a. Calculate the current through the resistance

A
24.0 V

V
6O
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b. What thermal energy is supplied by the heater
in 10 seconds? (HINT- use the equation E I2Rt
to determine energy)

A
24.0 V

V
6O
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7. Use the circuit diagram to the right to answer
the following questions. a. What is the current
flowing through this series circuit if the total
resistance is 20 O?
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b. What would the voltage across each of the
three bulbs be? What could you say about the
brightness of each of the bulbs?
Therefore each bulb would have 8 volts and the
same brightness
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c. If two of the bulbs had a total resistance of
15 O, what would the resistance of the third bulb
be?
If the total resistance equals 20 ohms, then the
remaining resistor would have a value of 5
ohms (20 15 5)
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d. What would be the current flowing through the
circuit be is the voltage source was 6.0 V, and
each of the lamps had a resistance of 2 O?
2O
6.0V
2O
2O
First calculate total resistance Then plug into
equation for current
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8. Draw a circuit diagram showing three 10 O
resistors connected in parallel and placed across
a 60.0 V battery.

A
60.0 V

10O
10O
10O
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a. What is the equivalent resistance of
the parallel circuit?

A
60.0 V

10O
10O
10O
Cross multiply and get
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b. What is the current through the entire circuit?
R 3.3 O (from earlier problem)

A
60.0 V

10O
10O
10O
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c. What is the current through each branch of the
circuit?

A
60.0 V

10O
10O
10O
Since the voltage and resistance are the same in
each branch they would have the same current
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9. Draw a circuit diagram showing the following
a 800.0 O resistor, a 40 O resistor, and a 20 O
resistor connected in parallel and connected
across a 24.0 V battery.

A
24.0 V

40O
800O
20O
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a. What is the equivalent resistance of
the parallel circuit?

A
24.0 V

40O
800O
20O
Cross multiply and get
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b. What is the current through the entire
circuit?
From above problem

A
24.0 V

40O
800O
20O
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c. What is the current through each branch of the
circuit?

A
24.0 V

40O
800O
20O
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10. Answer the following questions about the
circuit to the right. a. What do each of the 4
voltmeters read?
6V
In a parallel circuit, the voltage is the same
through each branch and divided by the number of
resistors in each branch. Therefore VA 6 V VB
6 V VC 3 V and VD 3 V (voltage is
split between the two resistors in that branch
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b. If each of the resistors are identical, and
the total current flowing through this parallel
circuit is 12.0 A, what is the total resistance
of this circuit?
6V