LADWP BASIC ELECTRICITY
COMPREHENSIVE PRACTICE EXAM WITH
QUESTIONS AND VERIFIED ANSWERS,
PLUS DETAILED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. Which statement most accurately describes electric current in a
metallic conductor?
A. It is the electrical pressure that causes electrons to move
B. It is the opposition encountered by electrons as they move
C. It is the rate at which electric charge flows past a point
D. It is the ability of a material to resist magnetic fields
Answer: C. The rate at which electric charge flows past a point
Rationale: Electric current is the rate of flow of electric charge and is
measured in amperes (A). In a metallic conductor, the moving charge
carriers are primarily electrons. Voltage is the electrical potential
difference that provides the driving force, while resistance opposes
current. The distinction is fundamental: voltage is the electrical
"push," current is the resulting rate of charge flow, and resistance is
the opposition to that flow.
2. A circuit has a resistance of 12 Ω and is connected to a 120-V
source. What current should theoretically flow through the circuit?
A. 0.1 A
B. 10 A
1
,C. 120 A
D. 1 A
Answer: B. 10 A
Rationale: Ohm's law states I = V/R. Substituting the given values
gives I = 120 V ÷ 12 Ω = 10 A. This relationship also demonstrates
that, with resistance held constant, increasing voltage increases
current proportionally. A common mistake is to multiply voltage by
resistance rather than divide voltage by resistance when solving for
current.
3. Which equation correctly represents Ohm's law?
A. V = I × R
B. P = V × I
C. I = V × R
D. R = V × I
Answer: A. V = I × R
Rationale: Ohm's law establishes the relationship between voltage,
current, and resistance: V = IR. The equation can be rearranged to
solve for any of the three quantities: I = V/R and R = V/I. Although P
= VI is also an important electrical equation, it is the power equation
rather than Ohm's law.
4. If the resistance of a circuit remains constant while the applied
voltage is doubled, what happens to the current?
A. It is reduced by half
B. It remains unchanged
C. It becomes four times greater
D. It doubles
2
,Answer: D. It doubles
Rationale: From Ohm's law, I = V/R. If R remains constant, current is
directly proportional to voltage. Therefore, doubling the voltage
produces twice the current. For example, a 10-V source producing 2 A
through a fixed resistance would produce 4 A if the voltage were
increased to 20 V, assuming the resistance remains unchanged.
5. Which electrical quantity is measured in ohms?
A. Current
B. Resistance
C. Power
D. Charge
Answer: B. Resistance
Rationale: The ohm (Ω) is the SI unit of electrical resistance.
Resistance describes the opposition a material or component presents
to current flow. Current is measured in amperes, power in watts, and
electric charge in coulombs. Understanding these units is essential for
interpreting electrical measurements and solving circuit problems.
6. A 24-V source is connected across a 6-Ω resistor. What is the
power dissipated by the resistor?
A. 4 W
B. 24 W
C. 96 W
D. 144 W
Answer: C. 96 W
Rationale: First calculate current using Ohm's law: I = V/R = 24/6 = 4
A. Then calculate power using P = VI: P = 24 × 4 = 96 W. The same
3
, result can be obtained using P = V²/R = 24²/6 = 96 W. This illustrates
how voltage, current, resistance, and power are mathematically
interconnected.
7. Which material is generally considered the best conductor among
the following?
A. Copper
B. Rubber
C. Glass
D. Porcelain
Answer: A. Copper
Rationale: Copper has relatively low electrical resistance and is widely
used for conductors, wiring, bus bars, and electrical equipment.
Rubber, glass, and porcelain are generally insulators and are used
where electrical isolation is required. Copper's combination of
conductivity, mechanical properties, and availability makes it
especially useful in electrical systems.
8. What is the primary reason electrical conductors have
comparatively low resistance?
A. They contain no atoms
B. Their electrons are relatively free to move
C. They prevent magnetic fields from forming
D. Their voltage is always zero
Answer: B. Their electrons are relatively free to move
Rationale: Conductive materials contain electrons that can move
relatively freely through the material. This mobility permits electric
charge to flow when an electric field is applied. Insulating materials
4
COMPREHENSIVE PRACTICE EXAM WITH
QUESTIONS AND VERIFIED ANSWERS,
PLUS DETAILED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. Which statement most accurately describes electric current in a
metallic conductor?
A. It is the electrical pressure that causes electrons to move
B. It is the opposition encountered by electrons as they move
C. It is the rate at which electric charge flows past a point
D. It is the ability of a material to resist magnetic fields
Answer: C. The rate at which electric charge flows past a point
Rationale: Electric current is the rate of flow of electric charge and is
measured in amperes (A). In a metallic conductor, the moving charge
carriers are primarily electrons. Voltage is the electrical potential
difference that provides the driving force, while resistance opposes
current. The distinction is fundamental: voltage is the electrical
"push," current is the resulting rate of charge flow, and resistance is
the opposition to that flow.
2. A circuit has a resistance of 12 Ω and is connected to a 120-V
source. What current should theoretically flow through the circuit?
A. 0.1 A
B. 10 A
1
,C. 120 A
D. 1 A
Answer: B. 10 A
Rationale: Ohm's law states I = V/R. Substituting the given values
gives I = 120 V ÷ 12 Ω = 10 A. This relationship also demonstrates
that, with resistance held constant, increasing voltage increases
current proportionally. A common mistake is to multiply voltage by
resistance rather than divide voltage by resistance when solving for
current.
3. Which equation correctly represents Ohm's law?
A. V = I × R
B. P = V × I
C. I = V × R
D. R = V × I
Answer: A. V = I × R
Rationale: Ohm's law establishes the relationship between voltage,
current, and resistance: V = IR. The equation can be rearranged to
solve for any of the three quantities: I = V/R and R = V/I. Although P
= VI is also an important electrical equation, it is the power equation
rather than Ohm's law.
4. If the resistance of a circuit remains constant while the applied
voltage is doubled, what happens to the current?
A. It is reduced by half
B. It remains unchanged
C. It becomes four times greater
D. It doubles
2
,Answer: D. It doubles
Rationale: From Ohm's law, I = V/R. If R remains constant, current is
directly proportional to voltage. Therefore, doubling the voltage
produces twice the current. For example, a 10-V source producing 2 A
through a fixed resistance would produce 4 A if the voltage were
increased to 20 V, assuming the resistance remains unchanged.
5. Which electrical quantity is measured in ohms?
A. Current
B. Resistance
C. Power
D. Charge
Answer: B. Resistance
Rationale: The ohm (Ω) is the SI unit of electrical resistance.
Resistance describes the opposition a material or component presents
to current flow. Current is measured in amperes, power in watts, and
electric charge in coulombs. Understanding these units is essential for
interpreting electrical measurements and solving circuit problems.
6. A 24-V source is connected across a 6-Ω resistor. What is the
power dissipated by the resistor?
A. 4 W
B. 24 W
C. 96 W
D. 144 W
Answer: C. 96 W
Rationale: First calculate current using Ohm's law: I = V/R = 24/6 = 4
A. Then calculate power using P = VI: P = 24 × 4 = 96 W. The same
3
, result can be obtained using P = V²/R = 24²/6 = 96 W. This illustrates
how voltage, current, resistance, and power are mathematically
interconnected.
7. Which material is generally considered the best conductor among
the following?
A. Copper
B. Rubber
C. Glass
D. Porcelain
Answer: A. Copper
Rationale: Copper has relatively low electrical resistance and is widely
used for conductors, wiring, bus bars, and electrical equipment.
Rubber, glass, and porcelain are generally insulators and are used
where electrical isolation is required. Copper's combination of
conductivity, mechanical properties, and availability makes it
especially useful in electrical systems.
8. What is the primary reason electrical conductors have
comparatively low resistance?
A. They contain no atoms
B. Their electrons are relatively free to move
C. They prevent magnetic fields from forming
D. Their voltage is always zero
Answer: B. Their electrons are relatively free to move
Rationale: Conductive materials contain electrons that can move
relatively freely through the material. This mobility permits electric
charge to flow when an electric field is applied. Insulating materials
4
