,LADWP Electrical Craft Helper Exam 2026 – Practice
Questions, Verified Answers & Detailed Rationales
SECTION 1: ELECTRICAL FUNDAMENTALS & OHM'S LAW (Q1–Q40)
Question 1
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). A volt
measures electrical pressure, an ampere measures current flow, and a watt measures power.
Question 2
Which material is the best conductor of electricity?
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 a metallic element
with a single free electron in its outer shell, making it an excellent conductor of electricity.
Question 3
What is the formula for Ohm's Law?
A) V = I × R
B) V = I / R
,C) V = R / I
D) V = I² × R
Correct Answer: A
Rationale: Ohm's Law states that voltage equals current multiplied by resistance (V = I × R). This
is a fundamental relationship in electrical circuits.
Question 4
An electrical circuit has a resistance of 12 ohms and is connected to a 120-volt source. Using
Ohm's law, approximately how much current should flow?
A) 0.1 A
B) 10 A
C) 120 A
D) 1,440 A
Correct Answer: B
Rationale: Ohm's law states I = V / R. Therefore, 120 volts ÷ 12 ohms = 10 amperes.
Understanding this relationship helps a helper recognize whether measured current is
reasonable for a circuit.
Question 5
In a DC series circuit, if the resistance is doubled while the voltage remains constant, what
happens to the current?
A) It doubles.
B) It halves.
C) It remains the same.
D) It quadruples.
Correct Answer: B
Rationale: According to Ohm's Law (I = V / R), current is inversely proportional to resistance. If
resistance (R) is doubled and voltage (V) is constant, the current (I) will be reduced by half.
Question 6
, A 120-volt branch circuit supplies a lighting load drawing 8 amperes. If the circuit conductors
have negligible voltage drop and the load operates continuously, what is the approximate
electrical power consumed by the load?
A) 15 W
B) 120 W
C) 960 W
D) 1,440 W
Correct Answer: C
Rationale: Electrical power is calculated using P = V × I. Therefore, 120V × 8A = 960W. The other
values do not result from multiplying the given voltage and current.
Question 7
What is the total resistance of three 10Ω resistors connected in series?
A) 3.33 Ω
B) 10 Ω
C) 20 Ω
D) 30 Ω
Correct Answer: D
Rationale: In a series circuit, total resistance is the sum of individual resistances: 10Ω + 10Ω +
10Ω = 30Ω.
Question 8
What is the total resistance of three 10Ω resistors connected in parallel?
A) 3.33 Ω
B) 10 Ω
C) 20 Ω
D) 30 Ω
Correct Answer: A
Rationale: In a parallel circuit, total resistance is calculated as 1/R_T = 1/R1 + 1/R2 + 1/R3. For
three 10Ω resistors: 1/R_T = 0.1 + 0.1 + 0.1 = 0.3, so R_T = 1/0.3 ≈ 3.33Ω.
Question 9
Questions, Verified Answers & Detailed Rationales
SECTION 1: ELECTRICAL FUNDAMENTALS & OHM'S LAW (Q1–Q40)
Question 1
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). A volt
measures electrical pressure, an ampere measures current flow, and a watt measures power.
Question 2
Which material is the best conductor of electricity?
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 a metallic element
with a single free electron in its outer shell, making it an excellent conductor of electricity.
Question 3
What is the formula for Ohm's Law?
A) V = I × R
B) V = I / R
,C) V = R / I
D) V = I² × R
Correct Answer: A
Rationale: Ohm's Law states that voltage equals current multiplied by resistance (V = I × R). This
is a fundamental relationship in electrical circuits.
Question 4
An electrical circuit has a resistance of 12 ohms and is connected to a 120-volt source. Using
Ohm's law, approximately how much current should flow?
A) 0.1 A
B) 10 A
C) 120 A
D) 1,440 A
Correct Answer: B
Rationale: Ohm's law states I = V / R. Therefore, 120 volts ÷ 12 ohms = 10 amperes.
Understanding this relationship helps a helper recognize whether measured current is
reasonable for a circuit.
Question 5
In a DC series circuit, if the resistance is doubled while the voltage remains constant, what
happens to the current?
A) It doubles.
B) It halves.
C) It remains the same.
D) It quadruples.
Correct Answer: B
Rationale: According to Ohm's Law (I = V / R), current is inversely proportional to resistance. If
resistance (R) is doubled and voltage (V) is constant, the current (I) will be reduced by half.
Question 6
, A 120-volt branch circuit supplies a lighting load drawing 8 amperes. If the circuit conductors
have negligible voltage drop and the load operates continuously, what is the approximate
electrical power consumed by the load?
A) 15 W
B) 120 W
C) 960 W
D) 1,440 W
Correct Answer: C
Rationale: Electrical power is calculated using P = V × I. Therefore, 120V × 8A = 960W. The other
values do not result from multiplying the given voltage and current.
Question 7
What is the total resistance of three 10Ω resistors connected in series?
A) 3.33 Ω
B) 10 Ω
C) 20 Ω
D) 30 Ω
Correct Answer: D
Rationale: In a series circuit, total resistance is the sum of individual resistances: 10Ω + 10Ω +
10Ω = 30Ω.
Question 8
What is the total resistance of three 10Ω resistors connected in parallel?
A) 3.33 Ω
B) 10 Ω
C) 20 Ω
D) 30 Ω
Correct Answer: A
Rationale: In a parallel circuit, total resistance is calculated as 1/R_T = 1/R1 + 1/R2 + 1/R3. For
three 10Ω resistors: 1/R_T = 0.1 + 0.1 + 0.1 = 0.3, so R_T = 1/0.3 ≈ 3.33Ω.
Question 9
