ASVAB Electronics Practice Test 1 ā Questions and Answers
Question 1: Electrical power can be calculated with the following formula: P = I x V What does the letter I represent in this formula?
- watts
- voltage
- current (Correct answer)
- impedance
Correct answer: current
In the fundamental electrical power formula P = I x V, 'P' stands for power (measured in watts), 'V' stands for voltage (measured in volts), and 'I' represents electrical current. Current is the flow of electric charge and is typically measured in amperes (amps).
Question 2: What is the load in this basic circuit model?
- A
- B
- C (Correct answer)
- D
Correct answer: C
In a basic circuit model (image not provided), the load is the component that consumes electrical energy and converts it into another form, such as light, heat, or motion. Assuming 'C' points to such a component in the unseen diagram, it represents the load, which is the part of the circuit doing the useful work.
Question 3: Three amps equals how many milliamps?
- 0.003
- 30
- 300
- 3,000 (Correct answer)
Correct answer: 3,000
The prefix "milli-" denotes one-thousandth (1/1000) of a unit. Therefore, 1 amp is equal to 1,000 milliamps. To convert 3 amps to milliamps, you multiply 3 by 1,000. This calculation results in 3,000 milliamps.
Question 4: What type of electrical circuit is depicted above?
- simple circuit
- series circuit
- parallel circuit
- series-parallel circuit (Correct answer)
Correct answer: series-parallel circuit
A series-parallel circuit has some loads wired in series and some loads wired in parallel. The loads in this circuit are R1, R2, and R3. R1 is wired in series while R2 and R3 are wired in parallel.
Question 5: What device would you use to measure electrical resistance in a circuit.
- ohmmeter (Correct answer)
- voltmeter
- ammeter
- electricity meter
Correct answer: ohmmeter
Electrical resistance is measured in ohms, and can be measured with an ohmmeter.
Question 6: Which of the following is NOT a type of resistor?
- potentiometer
- dielectric (Correct answer)
- rheostat
- variable
Correct answer: dielectric
A potentiometer is a three terminal resistor with a sliding contact. A rheostat is a two terminal variable resistor. A variable resistor is any resistor that allows you to change the amount of resistance. Potentiometers and rheostats are both types of variable resistors.
Question 7: Which of these electrical devices can be used to store an electric charge?
- Semiconductor
- Diode
- Capacitor (Correct answer)
- Transistor
Correct answer: Capacitor
Capacitors consist of one or more pairs of metal conducting plates that are separated by an insulator. The insulator is called the dielectric. An electric charge builds up when a voltage is applied across the plates, which creates an electric field.
Question 8: The amount of energy used by a consumer in their home or business is typically measured in
- current
- amps
- voltage
- kilowatt-hours (Correct answer)
Correct answer: kilowatt-hours
A kilowatt-hour (kWh) is a unit of energy equivalent to one kilowatt (1 kW) of power expended for one hour
Question 9: AM radio stations broadcast in which frequency range?
- 530-1,700 kHz (Correct answer)
- 7-1,002 MHz
- 1-40 GHz
- 60-1,000 AHz
Correct answer: 530-1,700 kHz
Frequencies are measured in kilohertz, megahertz, or gigahertz. AM radio stations broadcast in the 530-1,700 kHz range.
Question 10: If a circuit has 8 volts of power and 4 ohms of resistance, what will the current equal?
- 1\/2 amp
- 2 amps (Correct answer)
- 4 amps
- 8 amps
Correct answer: 2 amps
Current is measured in amps. The formula to use here is: I = V\/R \r\nI = 8\/4 \r\nI = 2
Question 11: Which of the following is the correct definition of an electrical cell?
- A method of grounding an electrical current to the ground.
- A system of transporting current from one part of a component to another.
- A device that is capable of changing some form of energy (such as chemical energy) into electricity. (Correct answer)
- An electrical device that can convert electric power into radio waves, and vice versa
Correct answer: A device that is capable of changing some form of energy (such as chemical energy) into electricity.
An electrical cell supplies electrical current. Examples include batteries and solar cells.
Question 12: What is the voltage in a circuit with 10 amps of current and 6 ohms of resistance?
- 0.6
- 1.7
- 60 (Correct answer)
- 600
Correct answer: 60
The formula to use here is: V = I x R \r\nV = 10 x 6 \r\nV = 60
Question 13: The resistor color code for 2 is
- Black
- Brown
- Red (Correct answer)
- Orange
Correct answer: Red
The band code for a resistor is as follows: \r\nā£\tBlack is 0 \r\nā£\tBrown is 1 \r\nā£\tRed is 2 \r\nā£\tOrange is 3 \r\nā£\tYellow is 4 \r\nā£\tGreen is 5 \r\nā£\tBlue is 6 \r\nā£\tViolet is 7 \r\nā£\tGray is 8 \r\nā£\tWhite is 9
Question 14: What type of switch is pictured above?
- simple on\/off
- changeover
- double pull double throw
- push-to-break (Correct answer)
Correct answer: push-to-break
Pushing the button breaks the circuit. When you release the button it returns to its normally closed (on) position.
Question 15: Which of the following is the SI unit representing one cycle per second?
- Ohm
- Frequency
- Ampere
- Hertz (Correct answer)
Correct answer: Hertz
The hertz, or Hz, is the SI unit of cycles per second and is a measurement of frequency. The Ohm is a measurement of resistance and the Ampere is a measurement of flow rate of electric charge.
Question 16: Which of the following is the most conductive element?
- Gold
- Silver (Correct answer)
- Aluminium
- Copper
Correct answer: Silver
The most conductive material is Silver followed by Copper and Gold.\r\n
Question 17: Which of the following statements are correct regarding a Voltmeter?
- A voltmeter is used to measure current.
- A voltmeter is used in parallel to a circuit. (Correct answer)
- A voltmeter must have the least resistance.
- All of the above
Correct answer: A voltmeter is used in parallel to a circuit.
A voltmeter is used to measure the potential difference between two points. It is used in parallel with a circuit when measuring voltage. Ideally a voltmeter should have high resistance so that no current flows through it while measuring the potential difference between the two points.\r\n
Question 18: Moderated by the voltage regulator, system voltage during regular car operation is around
- 10 volts
- 15 volts (Correct answer)
- 20 volts
- 25 volts
Correct answer: 15 volts
Normally, the system voltage is around 14.5 volts. Car accessories increase the demand on the system (dropping the voltage) but this is compensated by the voltage regulator, which increases the alternator's output until the system voltage is back to approximately 15.
ASVAB Electronics Practice Test 1
Electrical power can be calculated with the following formula: P = I x V What does the letter I represent in this formula?