LADWP ELECTRICAL CRAFT HELPER
Examination 2026–2027 | Comprehensive 300-
Question Practice Test with Answers &
Rationales| Free Pdf Access.
Question 1 of 300
What is the unit of measurement for electrical resistance?
□
A. Volt
□
B. Ampere
] C. Ohm
□
D. Watt
Correct Answer: C
Rationale: Resistance is measured in ohms (Ω), as defined by Ohm's Law (V = I × R). Volts
measure voltage (electromotive force), amperes measure current, and watts measure
power. The ohm is the fundamental unit of electrical resistance .
Question 2 of 300
, [FLAG QUESTION]
Which material is the best conductor of electricity among common wiring materials?
□
A. Aluminum
□
B. Copper
] C. Steel
□
D. PVC
Correct Answer: B
Rationale: Copper has the highest conductivity among common wiring materials,
surpassing aluminum and far exceeding non-conductors like steel or PVC. Copper is the
industry standard for electrical conductors due to its excellent conductivity, corrosion
resistance, and workability .
Question 3 of 300
[FLAG QUESTION]
What is the standard frequency of AC power supplied in the United States?
□
A. 25 Hz
□
B. 50 Hz
] C. 60 Hz
□
, D. 100 Hz
Correct Answer: C
Rationale: U.S. utility grids operate at 60 hertz (Hz), whereas many other countries use 50
Hz. This is the standard frequency for alternating current in the United States .
Question 4 of 300
[FLAG QUESTION]
In a series circuit, if one component fails open, what happens to the entire circuit?
□
A. The circuit continues to operate normally
□
B. The circuit stops functioning completely
] C. Voltage increases in other components
□
D. Current increases in other components
Correct Answer: B
Rationale: In a series circuit, there is only one path for current flow. If one component fails
open, the path is broken and the entire circuit becomes inoperative. All current stops
flowing .
Question 5 of 300
[FLAG QUESTION]
In a parallel circuit, if one branch fails open, what happens to the other branches?
, □
A. All branches stop working
□
B. Other branches continue to operate normally
] C. Voltage increases in other branches
□
D. Current decreases in all branches
Correct Answer: B
Rationale: In a parallel circuit, each branch provides an independent path for current. If
one branch fails open, the other branches continue to operate normally. This is a key
advantage of parallel circuits in electrical distribution systems .
Question 6 of 300
[FLAG QUESTION]
What is the correct formula for Ohm's Law?
□
A. V = I / R
□
B. V = I × R
] C. V = R / I
□
D. V = P × I
Correct Answer: B
Examination 2026–2027 | Comprehensive 300-
Question Practice Test with Answers &
Rationales| Free Pdf Access.
Question 1 of 300
What is the unit of measurement for electrical resistance?
□
A. Volt
□
B. Ampere
] C. Ohm
□
D. Watt
Correct Answer: C
Rationale: Resistance is measured in ohms (Ω), as defined by Ohm's Law (V = I × R). Volts
measure voltage (electromotive force), amperes measure current, and watts measure
power. The ohm is the fundamental unit of electrical resistance .
Question 2 of 300
, [FLAG QUESTION]
Which material is the best conductor of electricity among common wiring materials?
□
A. Aluminum
□
B. Copper
] C. Steel
□
D. PVC
Correct Answer: B
Rationale: Copper has the highest conductivity among common wiring materials,
surpassing aluminum and far exceeding non-conductors like steel or PVC. Copper is the
industry standard for electrical conductors due to its excellent conductivity, corrosion
resistance, and workability .
Question 3 of 300
[FLAG QUESTION]
What is the standard frequency of AC power supplied in the United States?
□
A. 25 Hz
□
B. 50 Hz
] C. 60 Hz
□
, D. 100 Hz
Correct Answer: C
Rationale: U.S. utility grids operate at 60 hertz (Hz), whereas many other countries use 50
Hz. This is the standard frequency for alternating current in the United States .
Question 4 of 300
[FLAG QUESTION]
In a series circuit, if one component fails open, what happens to the entire circuit?
□
A. The circuit continues to operate normally
□
B. The circuit stops functioning completely
] C. Voltage increases in other components
□
D. Current increases in other components
Correct Answer: B
Rationale: In a series circuit, there is only one path for current flow. If one component fails
open, the path is broken and the entire circuit becomes inoperative. All current stops
flowing .
Question 5 of 300
[FLAG QUESTION]
In a parallel circuit, if one branch fails open, what happens to the other branches?
, □
A. All branches stop working
□
B. Other branches continue to operate normally
] C. Voltage increases in other branches
□
D. Current decreases in all branches
Correct Answer: B
Rationale: In a parallel circuit, each branch provides an independent path for current. If
one branch fails open, the other branches continue to operate normally. This is a key
advantage of parallel circuits in electrical distribution systems .
Question 6 of 300
[FLAG QUESTION]
What is the correct formula for Ohm's Law?
□
A. V = I / R
□
B. V = I × R
] C. V = R / I
□
D. V = P × I
Correct Answer: B
