NCCER Electrical 1 — Questions and Answers
Question 1: What is the unit of measurement for electrical resistance?
- Ampere
- Volt
- Ohm (Correct answer)
- Watt
Correct answer: Ohm
Electrical resistance is measured in ohms, the unit named after physicist Georg Simon Ohm.
Question 2: According to Ohm's Law, if voltage remains constant and resistance doubles, what happens to current?
- Current doubles
- Current is reduced by half (Correct answer)
- Current remains the same
- Current increases by four times
Correct answer: Current is reduced by half
Ohm's Law states I = V/R; when R doubles with constant V, current (I) is reduced by half.
Question 3: Which type of circuit provides only one path for current to flow through all components?
- Parallel circuit
- Series circuit (Correct answer)
- Combination circuit
- Bridge circuit
Correct answer: Series circuit
In a series circuit, components are connected end-to-end in a single loop, providing only one path for current flow.
Question 4: What color is the grounding conductor required to be in standard US electrical wiring?
- White
- Black
- Red
- Green (Correct answer)
Correct answer: Green
The NEC requires equipment grounding conductors to be green, green with yellow stripes, or bare copper.
Question 5: What does GFCI stand for in electrical work?
- Ground Fault Circuit Interrupter (Correct answer)
- Ground Fault Current Indicator
- General Fault Circuit Interrupter
- Ground Flow Current Interrupter
Correct answer: Ground Fault Circuit Interrupter
GFCI stands for Ground Fault Circuit Interrupter, a device that detects ground faults and cuts power to prevent electrical shock.
Question 6: What is the standard nominal voltage for most residential branch circuits in the United States?
- 110 volts
- 120 volts (Correct answer)
- 240 volts
- 480 volts
Correct answer: 120 volts
Standard US residential branch circuits operate at 120 volts nominal, which is what you measure at a typical wall outlet.
Question 7: Which instrument is used to measure electrical current flowing through a circuit?
- Voltmeter
- Ohmmeter
- Ammeter (Correct answer)
- Wattmeter
Correct answer: Ammeter
An ammeter measures electrical current in amperes and must be connected in series with the circuit being tested.
NCCER Electrical 1
What is the unit of measurement for electrical resistance?