Electrical Technician Practice Test (100 Questions
with Answers and Rationales) – Complete Exam
Preparation Guide
1. What is the unit of electrical resistance?
a) Volt
b) Ampere
c) Ohm
d) Watt
c) Ohm
Resistance is measured in ohms, symbolized by the Greek letter omega
(Ω).
2. Which device is used to measure electric current?
a) Voltmeter
b) Ammeter
c) Ohmmeter
d) Wattmeter
b) Ammeter
An ammeter is connected in series to measure the flow of current in
amperes.
3. What does a transformer do?
a) Converts AC to DC
b) Converts DC to AC
, c) Changes voltage levels
d) Measures electrical power
c) Changes voltage levels
Transformers change AC voltage levels either by stepping it up or stepping
it down.
4. The formula for power in an electrical circuit is:
a) P = V × I
b) P = V / I
c) P = I² × R
d) Both a and c
d) Both a and c
Power (P) can be calculated as voltage times current (P=VI) or current
squared times resistance (P=I²R).
5. What color is the ground wire in electrical wiring?
a) Black
b) White
c) Green or bare copper
d) Red
c) Green or bare copper
The ground wire is typically green or bare copper for safety grounding.
6. What type of current is supplied by a typical household electrical outlet?
a) DC
b) AC
c) Pulsed DC
, d) None of the above
b) AC
Household outlets provide alternating current (AC), usually at 120V or
240V depending on country.
7. What is the standard voltage for residential power supply in the United
States?
a) 120V
b) 230V
c) 12V
d) 240V
a) 120V
In the US, standard residential voltage is 120 volts AC.
8. Which component limits current flow in a circuit?
a) Resistor
b) Capacitor
c) Inductor
d) Diode
a) Resistor
Resistors oppose current flow by providing resistance measured in ohms.
9. What is the main function of a capacitor?
a) Store electrical energy
b) Convert AC to DC
c) Limit current flow
d) Amplify signals
, a) Store electrical energy
Capacitors store electrical energy temporarily in an electric field.
10.What does an ohmmeter measure?
a) Voltage
b) Current
c) Resistance
d) Power
c) Resistance
An ohmmeter is used to measure the resistance in a circuit or component.
11.What is the purpose of a circuit breaker?
a) Provide continuous current flow
b) Break the circuit when current overload occurs
c) Measure current
d) Convert AC to DC
b) Break the circuit when current overload occurs
Circuit breakers protect electrical circuits by interrupting current flow
during overloads or faults.
12.What safety equipment should be worn when working with live electrical
circuits?
a) Rubber gloves
b) Safety goggles
c) Insulated boots
d) All of the above
d) All of the above
with Answers and Rationales) – Complete Exam
Preparation Guide
1. What is the unit of electrical resistance?
a) Volt
b) Ampere
c) Ohm
d) Watt
c) Ohm
Resistance is measured in ohms, symbolized by the Greek letter omega
(Ω).
2. Which device is used to measure electric current?
a) Voltmeter
b) Ammeter
c) Ohmmeter
d) Wattmeter
b) Ammeter
An ammeter is connected in series to measure the flow of current in
amperes.
3. What does a transformer do?
a) Converts AC to DC
b) Converts DC to AC
, c) Changes voltage levels
d) Measures electrical power
c) Changes voltage levels
Transformers change AC voltage levels either by stepping it up or stepping
it down.
4. The formula for power in an electrical circuit is:
a) P = V × I
b) P = V / I
c) P = I² × R
d) Both a and c
d) Both a and c
Power (P) can be calculated as voltage times current (P=VI) or current
squared times resistance (P=I²R).
5. What color is the ground wire in electrical wiring?
a) Black
b) White
c) Green or bare copper
d) Red
c) Green or bare copper
The ground wire is typically green or bare copper for safety grounding.
6. What type of current is supplied by a typical household electrical outlet?
a) DC
b) AC
c) Pulsed DC
, d) None of the above
b) AC
Household outlets provide alternating current (AC), usually at 120V or
240V depending on country.
7. What is the standard voltage for residential power supply in the United
States?
a) 120V
b) 230V
c) 12V
d) 240V
a) 120V
In the US, standard residential voltage is 120 volts AC.
8. Which component limits current flow in a circuit?
a) Resistor
b) Capacitor
c) Inductor
d) Diode
a) Resistor
Resistors oppose current flow by providing resistance measured in ohms.
9. What is the main function of a capacitor?
a) Store electrical energy
b) Convert AC to DC
c) Limit current flow
d) Amplify signals
, a) Store electrical energy
Capacitors store electrical energy temporarily in an electric field.
10.What does an ohmmeter measure?
a) Voltage
b) Current
c) Resistance
d) Power
c) Resistance
An ohmmeter is used to measure the resistance in a circuit or component.
11.What is the purpose of a circuit breaker?
a) Provide continuous current flow
b) Break the circuit when current overload occurs
c) Measure current
d) Convert AC to DC
b) Break the circuit when current overload occurs
Circuit breakers protect electrical circuits by interrupting current flow
during overloads or faults.
12.What safety equipment should be worn when working with live electrical
circuits?
a) Rubber gloves
b) Safety goggles
c) Insulated boots
d) All of the above
d) All of the above
