Cslb C10 Exam 1-3 Actual Test 2026-2027
With Complete Accurate Questions And
Correct Detailed Answers (Correct
Verified Solutions) A New Updated
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1. What does the C-10 classification primarily cover?
A. Electrical contracting
B. Plumbing contracting
C. Roofing contracting
D. Landscaping contracting
Answer: A
Rationale: California's C-10 classification is for electrical contracting, including electrical systems
and related work within its scope.
2. What is the primary purpose of the California Electrical Code?
A. Establish minimum electrical safety requirements
B. Set contractor profit margins
C. Establish material retail prices
D. Determine employee wages
Answer: A
Rationale: Electrical codes establish minimum requirements intended to protect people and
property from electrical hazards.
3. Which organization publishes the National Electrical Code (NEC)?
A. NFPA
B. OSHA
C. EPA
D. ANSI alone
,Answer: A
Rationale: The National Fire Protection Association publishes NFPA 70, commonly known as the
NEC.
4. What is the main function of a circuit breaker?
A. Protect conductors from overcurrent
B. Increase voltage
C. Store electrical energy
D. Reduce conductor resistance
Answer: A
Rationale: Circuit breakers interrupt current when an overcurrent condition occurs, helping
protect conductors and equipment.
5. A fuse protects a circuit primarily by:
A. Opening when excessive current causes the fusible element to operate
B. Increasing current capacity
C. Increasing voltage
D. Storing current
Answer: A
Rationale: A fuse contains an element designed to open the circuit when excessive current
flows.
6. Which unit measures electrical current?
A. Ampere
B. Volt
C. Ohm
D. Watt
Answer: A
Rationale: Current is measured in amperes, commonly abbreviated A.
7. Which unit measures electrical resistance?
A. Ohm
B. Ampere
,C. Volt
D. Watt
Answer: A
Rationale: Electrical resistance is measured in ohms, represented by Ω.
8. Which unit measures electrical potential difference?
A. Volt
B. Ampere
C. Ohm
D. Watt
Answer: A
Rationale: Voltage is the electrical potential difference between two points.
9. Which formula represents Ohm's law?
A. V = I × R
B. P = I ÷ R
C. R = V × I
D. I = V × R
Answer: A
Rationale: Ohm's law states that voltage equals current multiplied by resistance.
10. A 120 V circuit has a resistance of 20 Ω. What current flows?
A. 6 A
B. 20 A
C. 120 A
D. 2 A
Answer: A
Rationale: I = V ÷ R = 120 ÷ 20 = 6 A.
11. What is the electrical power formula?
A. P = V × I
B. P = V ÷ I
, C. P = R ÷ I
D. P = I ÷ V
Answer: A
Rationale: Electrical power in a basic DC/resistive calculation is voltage multiplied by current.
12. A 120 V load draws 10 A. What is its power?
A. 1,200 W
B. 120 W
C. 12 W
D. 12,000 W
Answer: A
Rationale: P = V × I = 120 × 10 = 1,200 W.
13. What happens to current in a series circuit when resistance increases while voltage
remains constant?
A. Current decreases
B. Current increases
C. Current becomes infinite
D. Voltage becomes zero
Answer: A
Rationale: According to Ohm's law, increasing resistance at constant voltage reduces current.
14. In a parallel circuit, each branch is generally connected across the:
A. Same voltage source
B. Same resistor only
C. Grounding electrode only
D. Neutral conductor only
Answer: A
Rationale: Parallel branches are connected across the same two electrical nodes and therefore
have the same applied voltage.
With Complete Accurate Questions And
Correct Detailed Answers (Correct
Verified Solutions) A New Updated
Version Guaranteed Pass A+
1. What does the C-10 classification primarily cover?
A. Electrical contracting
B. Plumbing contracting
C. Roofing contracting
D. Landscaping contracting
Answer: A
Rationale: California's C-10 classification is for electrical contracting, including electrical systems
and related work within its scope.
2. What is the primary purpose of the California Electrical Code?
A. Establish minimum electrical safety requirements
B. Set contractor profit margins
C. Establish material retail prices
D. Determine employee wages
Answer: A
Rationale: Electrical codes establish minimum requirements intended to protect people and
property from electrical hazards.
3. Which organization publishes the National Electrical Code (NEC)?
A. NFPA
B. OSHA
C. EPA
D. ANSI alone
,Answer: A
Rationale: The National Fire Protection Association publishes NFPA 70, commonly known as the
NEC.
4. What is the main function of a circuit breaker?
A. Protect conductors from overcurrent
B. Increase voltage
C. Store electrical energy
D. Reduce conductor resistance
Answer: A
Rationale: Circuit breakers interrupt current when an overcurrent condition occurs, helping
protect conductors and equipment.
5. A fuse protects a circuit primarily by:
A. Opening when excessive current causes the fusible element to operate
B. Increasing current capacity
C. Increasing voltage
D. Storing current
Answer: A
Rationale: A fuse contains an element designed to open the circuit when excessive current
flows.
6. Which unit measures electrical current?
A. Ampere
B. Volt
C. Ohm
D. Watt
Answer: A
Rationale: Current is measured in amperes, commonly abbreviated A.
7. Which unit measures electrical resistance?
A. Ohm
B. Ampere
,C. Volt
D. Watt
Answer: A
Rationale: Electrical resistance is measured in ohms, represented by Ω.
8. Which unit measures electrical potential difference?
A. Volt
B. Ampere
C. Ohm
D. Watt
Answer: A
Rationale: Voltage is the electrical potential difference between two points.
9. Which formula represents Ohm's law?
A. V = I × R
B. P = I ÷ R
C. R = V × I
D. I = V × R
Answer: A
Rationale: Ohm's law states that voltage equals current multiplied by resistance.
10. A 120 V circuit has a resistance of 20 Ω. What current flows?
A. 6 A
B. 20 A
C. 120 A
D. 2 A
Answer: A
Rationale: I = V ÷ R = 120 ÷ 20 = 6 A.
11. What is the electrical power formula?
A. P = V × I
B. P = V ÷ I
, C. P = R ÷ I
D. P = I ÷ V
Answer: A
Rationale: Electrical power in a basic DC/resistive calculation is voltage multiplied by current.
12. A 120 V load draws 10 A. What is its power?
A. 1,200 W
B. 120 W
C. 12 W
D. 12,000 W
Answer: A
Rationale: P = V × I = 120 × 10 = 1,200 W.
13. What happens to current in a series circuit when resistance increases while voltage
remains constant?
A. Current decreases
B. Current increases
C. Current becomes infinite
D. Voltage becomes zero
Answer: A
Rationale: According to Ohm's law, increasing resistance at constant voltage reduces current.
14. In a parallel circuit, each branch is generally connected across the:
A. Same voltage source
B. Same resistor only
C. Grounding electrode only
D. Neutral conductor only
Answer: A
Rationale: Parallel branches are connected across the same two electrical nodes and therefore
have the same applied voltage.
