1.E: Self-Test 1
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What are the tiny particles that matter is made of called?
- Compounds
- Atoms
- Ions
- Protons and neutrons
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What are elements called that have atoms with electrons that are easily freed?
- Ions
- Conductors
- Insulators
- Elements
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Which of the following best describes copper?
- Conductor
- Insulator
- Semiconductor
- Valence electron
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Why are insulators useful?
- They transport an electrical charge.
- They do not transport an electrical charge.
- They readily release valence electrons.
- They will ionize easily when subjected to voltage.
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In what units is current measured?
- Volts
- Amperes
- Ohms
- EMF
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A source of electromotive force can be from a chemical reaction.
- True
- False
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In a DC circuit the poles alternate from positive to negative.
- True
- False
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What is the device called that is used to turn a circuit on and off?
- A control
- A conductor
- A load
- A protector
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Which of the following best describes an electric motor?
- A control
- A load
- A fuse
- A conductor
Use Ohm’s law for the following questions.
E = I × R, where:
- Volts (V) is represented by “E” for electromotive force.
- Amperes (A) is represented by “I” for intensity of current.
- Ohms (Ω) is represented by “R” for resistance.
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If resistance in a circuit is 6 Ω and the pressure is 24 V, what is the current flow?
- 2 A
- 4 A
- 6 A
- 8 A
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If a circuit had a current flow of 8 A and the resistance is 20 Ω, what is the pressure in volts?
- 120 V
- 160 V
- 2.5 V
- 25 V
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If a circuit has a current flow of 5 A and a pressure of 120 V, what is the resistance?
- 24 Ω
- 12 Ω
- 6 Ω
- 3 Ω
Use the power formula for the following questions.
watts = volts × amps or P = E × I
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How much power will a heater produce if it uses 15 A in a 120 V electrical system?
- 1800 W
- 1500 W
- 900 W
- 1200 W
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How many amps will flow through a 60 W headlight bulb in a 24 V system?
- 6 A
- 2.5 A
- 25 A
- 8 A
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Use Ohm’s law to complete the following chart.
voltage
current
resistance
500 mA
240
12
1000
12
8 A
5
20 000
120
10
0.15 A
80
3
0.0002 A
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Use the power formula to complete the following chart.
power
voltage
current
1500 W
12.5 A
40 W
12 V
12 V
300 mA
200 W
10 A
96 W
12 V
12 V
40 A