Basic Electronics Practice Questions

Electronics questions are often included as part of mechanical aptitude (comprehension) questions.    The ASVAB and Elevator Repair Aptitude tests have electronics questions.

The following topics are usually covered: Circuits, Conductors, Short circuits, Open and Closed circuits, Load, Path, Parallel and Series Circuits.

1. Ohm’s law states

a. The voltage across a resistor is not equal to the product of the resistance and the current flowing through it.
b. The voltage across a resistor is equal to the product of the resistance and the current flowing through it.
c. The voltage across a resistor is greater than the product of the resistance.
d. The voltage across a resistor is equal to the current flowing through it.

2. What is the difference between alternating and direct current?

a. Direct current reverses direction periodically and alternating current flows in one direction.
b. Alternating current reverses direction and direct current flows in one direction.
c. Both alternating and direct current periodically reverse direction.
d. Both alternating and direct current flow in one direction only.

3. Is residential power AC or DC current?

a. Residential power is AC
b. Residential power is DC
c. Residential power is neither

4. Two wires run to a machine. One wire is 10mm thick, and the other is 5mm. If the two wires are carrying the same current, the larger wire:

a. Requires less voltage
b. Requires more voltage
c. Requires the same voltage
d. It cannot be determined from the information given

5. What device turns mechanical energy into electrical energy? 

a. Resistor
b. Capacitor
c. Voltmeter
d. Alternator

6. What is a resistive circuit?

a. A circuit that contains a power source and resistors
b. Any electrical circuit
c. A circuit that contains any combination of capacitors and resistors
d. None of the above

7. What are electrons? 

a. Subatomic particles that carry a negative charge
b. Subatomic particles that carry a positive charge
c. Subatomic particles that carry both a negative and positive charge
d. None of the above

8. An electric circuit is:

a. Conducting material from the load to the power source
b. Conducting material from the power source to the load
c. A loop of conducting material that goes from a power source to the load and back
d. None of the above

9. The load of an electric circuit is:

a. The length of the circuit
b. The amount of power consumed by a circuit
c. The impedance of a circuit
d. None of the above

10. What is the frequency? 

a. The number of complete cycles from one direction to the other
b. The resistance of a circuit
c. The voltage of a circuit
d. The impedance of a circuit

1. B
The voltage across a resistor is equal to the product of the resistance and the current flowing through it.

2. B
In alternating current (AC, also ac), the movement of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge is only in one direction.

3. A
Residential power is alternating current, AC.

4. A
If the two wires are carrying the same current, the larger wire requires less voltage.

5. D
An alternator is an electromagnetic device that turns mechanical energy into electrical energy.

6. A
A resistive circuit only contains a power source and resistors.

7. A
Electrons are subatomic particles that carry a negative charge.

8. C
A loop of conducting material that goes from a power source to the load and back.

9. B
The load is the amount of power consumed by a circuit.

10. A
Frequency is the number of complete cycles from one direction to the other.  Each time an AC current alternates, and the changes back is a complete cycle.