LADWP Electrical Helper Exam 2026 | Comprehensive Practice Examination |
High-Yield Questions, Answers & Detailed Rationales | Electrical Theory, Wiring,
Tools, Safety, Circuits, Motors & Basic Electrical Systems | Complete Exam Prep
Guide | Instant PDF Download
Question #1
What is the primary function of an electrical transformer in a power distribution system?
A. To convert alternating current to direct current
B. To change voltage levels while maintaining frequency
C. To store electrical energy for later use
D. To protect circuits from overload conditions
Correct Answer: B
Explanation: A transformer transfers electrical energy between circuits through electromagnetic
induction, changing voltage and current levels while maintaining the same frequency. This is essential
for efficient power transmission and distribution.
Question #2
According to Ohm's Law, if voltage remains constant and resistance decreases, what happens to
current?
A. Current decreases proportionally
B. Current remains unchanged
C. Current increases proportionally
D. Current becomes zero
,Correct Answer: C
Explanation: Ohm's Law states I = V/R. When voltage (V) is constant and resistance (R) decreases,
current (I) must increase proportionally. This inverse relationship is fundamental to understanding
electrical circuits.
Question #3
Which of the following best describes the relationship between power, voltage, and current in a DC
circuit?
A. P = V × I
B. P = V² × R
C. P = I² / R
D. P = V / I
Correct Answer: A
Explanation: Power in a DC circuit equals voltage multiplied by current (P = V × I). This fundamental
relationship is essential for calculating electrical power consumption and sizing electrical components.
Question #4
What is the primary difference between a series circuit and a parallel circuit?
A. Series circuits have higher voltage than parallel circuits
B. Series circuits have one path for current flow; parallel circuits have multiple paths
C. Parallel circuits use more energy than series circuits
D. Series circuits can only be used with alternating current
,Correct Answer: B
Explanation: In a series circuit, current flows through a single path, while parallel circuits provide
multiple pathways for current. This affects how voltage, current, and resistance behave in each
configuration.
Question #5
A circuit has a resistance of 100 ohms and a voltage of 120 volts. What is the current flowing through
the circuit?
A. 0.83 amperes
B. 1.20 amperes
C. 12.0 amperes
D. 120 amperes
Correct Answer: B
Explanation: Using Ohm's Law, I = V/R = 120/100 = 1.20 amperes. This calculation is fundamental for
determining current flow in electrical circuits and ensuring proper component sizing.
Question #6
What type of current flows in one direction only and maintains a constant polarity?
A. Alternating current
B. Direct current
C. Inductive current
D. Capacitive current
, Correct Answer: B
Explanation: Direct current (DC) flows in one direction with constant polarity. Batteries and solar
panels produce DC, while utility power is typically AC. Understanding this distinction is crucial for
electrical work.
Question #7
The frequency of alternating current in the United States is standardized at what value?
A. 50 Hz
B. 60 Hz
C. 100 Hz
D. 120 Hz
Correct Answer: B
Explanation: The U.S. electrical grid operates at 60 Hz, meaning current alternates direction 60 times
per second. This standard differs from many other countries that use 50 Hz, affecting equipment
compatibility.
Question #8
What phenomenon occurs when a conductor cuts through magnetic field lines, inducing voltage?
A. Electromagnetic induction
B. Electrostatic discharge
C. Dielectric breakdown
D. Eddy current formation
High-Yield Questions, Answers & Detailed Rationales | Electrical Theory, Wiring,
Tools, Safety, Circuits, Motors & Basic Electrical Systems | Complete Exam Prep
Guide | Instant PDF Download
Question #1
What is the primary function of an electrical transformer in a power distribution system?
A. To convert alternating current to direct current
B. To change voltage levels while maintaining frequency
C. To store electrical energy for later use
D. To protect circuits from overload conditions
Correct Answer: B
Explanation: A transformer transfers electrical energy between circuits through electromagnetic
induction, changing voltage and current levels while maintaining the same frequency. This is essential
for efficient power transmission and distribution.
Question #2
According to Ohm's Law, if voltage remains constant and resistance decreases, what happens to
current?
A. Current decreases proportionally
B. Current remains unchanged
C. Current increases proportionally
D. Current becomes zero
,Correct Answer: C
Explanation: Ohm's Law states I = V/R. When voltage (V) is constant and resistance (R) decreases,
current (I) must increase proportionally. This inverse relationship is fundamental to understanding
electrical circuits.
Question #3
Which of the following best describes the relationship between power, voltage, and current in a DC
circuit?
A. P = V × I
B. P = V² × R
C. P = I² / R
D. P = V / I
Correct Answer: A
Explanation: Power in a DC circuit equals voltage multiplied by current (P = V × I). This fundamental
relationship is essential for calculating electrical power consumption and sizing electrical components.
Question #4
What is the primary difference between a series circuit and a parallel circuit?
A. Series circuits have higher voltage than parallel circuits
B. Series circuits have one path for current flow; parallel circuits have multiple paths
C. Parallel circuits use more energy than series circuits
D. Series circuits can only be used with alternating current
,Correct Answer: B
Explanation: In a series circuit, current flows through a single path, while parallel circuits provide
multiple pathways for current. This affects how voltage, current, and resistance behave in each
configuration.
Question #5
A circuit has a resistance of 100 ohms and a voltage of 120 volts. What is the current flowing through
the circuit?
A. 0.83 amperes
B. 1.20 amperes
C. 12.0 amperes
D. 120 amperes
Correct Answer: B
Explanation: Using Ohm's Law, I = V/R = 120/100 = 1.20 amperes. This calculation is fundamental for
determining current flow in electrical circuits and ensuring proper component sizing.
Question #6
What type of current flows in one direction only and maintains a constant polarity?
A. Alternating current
B. Direct current
C. Inductive current
D. Capacitive current
, Correct Answer: B
Explanation: Direct current (DC) flows in one direction with constant polarity. Batteries and solar
panels produce DC, while utility power is typically AC. Understanding this distinction is crucial for
electrical work.
Question #7
The frequency of alternating current in the United States is standardized at what value?
A. 50 Hz
B. 60 Hz
C. 100 Hz
D. 120 Hz
Correct Answer: B
Explanation: The U.S. electrical grid operates at 60 Hz, meaning current alternates direction 60 times
per second. This standard differs from many other countries that use 50 Hz, affecting equipment
compatibility.
Question #8
What phenomenon occurs when a conductor cuts through magnetic field lines, inducing voltage?
A. Electromagnetic induction
B. Electrostatic discharge
C. Dielectric breakdown
D. Eddy current formation
