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ID: A
Chapter 20 Multi-format Test
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____
1. The unit of charge is the ohm. _________________________
____
2. An object with equal amounts of positive and negative charge is called electrically neutral.
_________________________
____
3. A complete path through which electricity travels is called a circuit. ________________________
____
4. In many circuit diagrams, any electrical device that uses energy is shown with a resistor symbol.
_________________________
____
5. A closed circuit has a break in it. _________________________
____
6. Differences in electric current cause charge to flow. _________________________
____
7. Electric current will flow easily through a insulator. _________________________
____
8. An ohm is the unit of measurement for current. _________________________
____
9. According to Ohm’s law, resistance is the ratio of voltage to current. _________________________
Completion
Complete each statement.
Select the correct term to complete each sentence. There are extra terms in the list.
voltage drop
current
static
decreases
circuit diagram
conductors
chemical
resistance
attract
increases
switch
insulators
nuclear
voltage
repel
electric charge
wire
light bulb
10. An tiny imbalance of electric charge on an object causes ____________________ electricity.
11. Two negative charges will ____________________ each other.
12. When we say current is moving through a circuit, we mean ____________________ is moving through the
circuit.
13. Short circuits cause the circuit to draw a large amount of ____________________.
14. A shorthand method of describing a real circuit using electrical symbols is called a(n)
____________________.
15. A device used to create an intentional break in a circuit to stop the flow of current is a(n)
____________________.
16. A battery transforms ____________________ energy into electrical energy.
17. A decrease in voltage across a component in a circuit is called a(n) ____________________.
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18. Materials through which charge flows easily are called ____________________.
19. Although AAA, AA, C, and D alkaline batteries differ in how long they last, they all have the same initial
____________________.
20. Tungsten is used in light bulb filaments because it glows when hot, rather than melting. The thin tungsten
filament gets very hot in a circuit because it has high ____________________.
21. As the temperature of a conductor increases, the resistance of the conductor ____________________.
Short Answer
22. Two positively charged objects are separated from each other by 1 centimeter. What is the direction of the
electrical force between them?
23. Why are circuit diagrams drawn?
24. To read the voltage, you accidentally connect the positive lead of a voltmeter to the negative terminal of a 1.5
volt battery and the negative lead to the positive terminal. What is the result?
25. You install two batteries in a flashlight so that their positive ends are facing each other. Will the flashlight
work? Why or why not?
26. Explain how a potentiometer is different from a fixed resistor.
Problem
27. A 120-volt household circuit has a fuse that breaks the circuit if more than 10 amps of current passes through
it. What is the minimum amount of resistance in the circuit required to keep the fuse from blowing?
28. If the current moving through the filament of a light bulb is 0.5 amps when the voltage across the bulb is 120
volts, what is the resistance of the bulb?
Essay
29. Describe a resistor and its function in a circuit.
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Other
The circuit pictured contains a light bulb connected to a voltage source that causes 2 amps of current through
the bulb.
Figure 20-2
30. Determine the resistance of the light bulb in Figure 20-2.
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Chapter 20 Multi-format Test
Answer Section
MODIFIED TRUE/FALSE
1. ANS: F, coulomb
2.
3.
4.
5.
DIF:
ANS:
ANS:
ANS:
ANS:
basic
T
T
T
F, open
REF: section 20.1
DIF: basic
6. ANS: F, voltage
REF: section 20.2
DIF: basic
7. ANS: F
conductor
electrical conductor
REF: section 20.3
DIF: basic
8. ANS: F, resistance
REF: section 20.3
DIF: basic
9. ANS: T
REF: section 20.4
DIF: basic
DIF: basic
DIF: basic
REF: section 20.1
REF: section 20.2
REF: section 20.2
DIF: basic
REF: section 20.4
COMPLETION
10. ANS: static
DIF: basic
11. ANS: attract
REF: section 20.1
DIF: basic
REF: section 20.1
12. ANS: electric charge
DIF: intermediate
13. ANS: current
REF: section 20.1
DIF: basic
REF: section 20.2
14. ANS: circuit diagram
DIF: basic
15. ANS: switch
DIF:
basic
REF: section 20.2
REF: section 20.2
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16. ANS: chemical
DIF: basic
17. ANS: voltage drop
REF: section 20.3
DIF: basic
18. ANS: conductors
REF: section 20.3
DIF: basic
19. ANS: voltage
REF: section 20.3
DIF: basic
20. ANS: resistance
REF: section 20.3
DIF: basic
21. ANS: increases
REF: section 20.4
DIF:
basic
REF: section 20.4
SHORT ANSWER
22. ANS:
The electrical force between them is a repulsive force, pushing the charges away from each other.
DIF: intermediate REF: section 20.1
23. ANS:
Circuit diagrams are drawn using symbols to represent the arrangement of components in a circuit because it
is easier and quicker than drawing realistic pictures of components.
DIF: intermediate REF: section 20.2
24. ANS:
The meter reads negative 1.5 volts or, if it is an analog meter, it may be “pinned” (go backwards against a
stop).
DIF: advanced
25. ANS:
REF: section 20.3
The flashlight will not work because the voltage, or potential difference, across the two batteries is zero.
Instead of the batteries’ voltages adding together, the voltages subtract from each other.
DIF: advanced
26. ANS:
REF: section 20.3
A potentiometer can be adjusted to give a range of resistance; a fixed resistor has a resistance that cannot be
changed.
DIF:
intermediate
REF: section 20.4
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PROBLEM
27. ANS:
V
120 volt
R=
=
= 12 ohms
I
10 amps
DIF: advanced
REF: section 20.3
28. ANS:
V 120 volts
R=
=
= 240 ohms = 240 Ω
I
0.5 amps
DIF:
intermediate
REF: section 20.4
ESSAY
29. ANS:
A resistor is an electrical component that is designed to have a specific resistance over a wide range of
currents. Resistors are used to control the amount of current in a circuit.
DIF:
intermediate
REF: section 20.4
OTHER
30. ANS:
V 1.5 volts + 1.5 volts
3 volts
R=
=
=
= 1.5 ohms
I
2 amps
2 amps
DIF:
advanced
REF: section 20.4
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Chapter 20 Multi-format Test [Answer Strip]
F
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1.
T
_____
2.
T
_____
3.
T
_____
4.
F
_____
5.
F
_____
6.
F
_____
7.
F
_____
8.
T
_____
9.
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