# 1.E: Self-Test 1

• • Contributed by Camosun College

Self-Test 1

1. What are the tiny particles that matter is made of called?
1. Compounds
2. Atoms
3. Ions
4. Protons and neutrons
2. What are elements called that have atoms with electrons that are easily freed?
1. Ions
2. Conductors
3. Insulators
4. Elements
3. Which of the following best describes copper?
1. Conductor
2. Insulator
3. Semiconductor
4. Valence electron
4. Why are insulators useful?
1. They transport an electrical charge.
2. They do not transport an electrical charge.
3. They readily release valence electrons.
4. They will ionize easily when subjected to voltage.
5. In what units is current measured?
1. Volts
2. Amperes
3. Ohms
4. EMF
6. A source of electromotive force can be from a chemical reaction.
1. True
2. False
1. In a DC circuit the poles alternate from positive to negative.
1. True
2. False
2. What is the device called that is used to turn a circuit on and off?
1. A control
2. A conductor
4. A protector
3. Which of the following best describes an electric motor?
1. A control
3. A fuse
4. 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.
1. If resistance in a circuit is 6 Ω and the pressure is 24 V, what is the current flow?
1. 2 A
2. 4 A
3. 6 A
4. 8 A
2. If a circuit had a current flow of 8 A and the resistance is 20 Ω, what is the pressure in volts?
1. 120 V
2. 160 V
3. 2.5 V
4. 25 V
1. If a circuit has a current flow of 5 A and a pressure of 120 V, what is the resistance?
1. 24 Ω
2. 12 Ω
3. 6 Ω
4. 3 Ω

Use the power formula for the following questions.

watts = volts × amps or P = E × I

1. How much power will a heater produce if it uses 15 A in a 120 V electrical system?
1. 1800 W
2. 1500 W
3. 900 W
4. 1200 W
2. How many amps will flow through a 60 W headlight bulb in a 24 V system?
1. 6 A
2. 2.5 A
3. 25 A
4. 8 A
3. 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
4. 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