NYC DCAS Electrician Exam Questions
With Correct Answers (Verified Answers)
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Q1. What is the unit of measurement for electrical resistance?
A) Ampere
B) Volt
C) Ohm
D) Watt
Correct ,,,answer,,,,: C
Rationale: The ohm (Ω) is the SI unit of electrical resistance, measuring
opposition to current flow .
Q2. According to Ohm's Law, voltage (V) equals:
A) Current × Resistance (I × R)
B) Power × Current (P × I)
C) Resistance ÷ Current (R ÷ I)
D) Current ÷ Resistance (I ÷ R)
Correct ,,,answer,,,,: A
Rationale: Ohm's Law states V = I × R, where V is voltage, I is current, and
R is resistance .
,Q3. What is the correct formula for calculating electrical power (P) in a
DC circuit?
A) P = I × R
B) P = V × I
C) P = V² / R
D) Both B and C
Correct ,,,answer,,,,: D
Rationale: Power can be calculated using P = V × I. Substituting Ohm's
Law gives P = V²/R or P = I² × R .
Q4. A 3-phase, 208V system supplies a 10 kW balanced load. What is
the approximate line current?
A) 27.8A
B) 34.7A
C) 48.1A
D) 60.0A
Correct ,,,answer,,,,: A
Rationale: I = P / (√3 × V) = 10,000W / (1.732 × 208V) ≈ 27.8A .
Q5. A conductor carrying electric current produces what type of field
around it?
A) Electrostatic field
B) Magnetic field
,C) Optical field
D) Thermal field
Correct ,,,answer,,,,: B
Rationale: Current flow generates a surrounding magnetic field—the
principle of electromagnetism used in motors and transformers .
Q6. In a three-phase wye-connected system, the line voltage is equal
to:
A) Phase voltage
B) Phase voltage × √3
C) Phase voltage ÷ √3
D) Phase voltage × 2
Correct ,,,answer,,,,: B
Rationale: Line voltage = phase voltage × √3 (approximately 1.732) due to
120° phase separation .
Q7. What is the primary purpose of a transformer in an electrical
system?
A) Change voltage levels through electromagnetic induction
B) Convert AC to DC
C) Increase conductor flexibility
D) Eliminate grounding requirements
, Correct ,,,answer,,,,: A
Rationale: Transformers use electromagnetic induction between primary
and secondary windings to step voltage up or down .
Q8. A transformer steps down voltage from 480V to 120V. What
happens to current if power remains constant?
A) Decreases
B) Increases
C) Remains the same
D) Becomes zero
Correct ,,,answer,,,,: B
Rationale: With constant power, lowering voltage increases current (P = V
× I) .
Q9. What is the function of a capacitor in an electrical circuit?
A) Store energy in a magnetic field
B) Store energy in an electric field
C) Increase resistance
D) Convert AC to DC
Correct ,,,answer,,,,: B
Rationale: Capacitors store energy in electrostatic fields between
conductive plates .
With Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf,
Q1. What is the unit of measurement for electrical resistance?
A) Ampere
B) Volt
C) Ohm
D) Watt
Correct ,,,answer,,,,: C
Rationale: The ohm (Ω) is the SI unit of electrical resistance, measuring
opposition to current flow .
Q2. According to Ohm's Law, voltage (V) equals:
A) Current × Resistance (I × R)
B) Power × Current (P × I)
C) Resistance ÷ Current (R ÷ I)
D) Current ÷ Resistance (I ÷ R)
Correct ,,,answer,,,,: A
Rationale: Ohm's Law states V = I × R, where V is voltage, I is current, and
R is resistance .
,Q3. What is the correct formula for calculating electrical power (P) in a
DC circuit?
A) P = I × R
B) P = V × I
C) P = V² / R
D) Both B and C
Correct ,,,answer,,,,: D
Rationale: Power can be calculated using P = V × I. Substituting Ohm's
Law gives P = V²/R or P = I² × R .
Q4. A 3-phase, 208V system supplies a 10 kW balanced load. What is
the approximate line current?
A) 27.8A
B) 34.7A
C) 48.1A
D) 60.0A
Correct ,,,answer,,,,: A
Rationale: I = P / (√3 × V) = 10,000W / (1.732 × 208V) ≈ 27.8A .
Q5. A conductor carrying electric current produces what type of field
around it?
A) Electrostatic field
B) Magnetic field
,C) Optical field
D) Thermal field
Correct ,,,answer,,,,: B
Rationale: Current flow generates a surrounding magnetic field—the
principle of electromagnetism used in motors and transformers .
Q6. In a three-phase wye-connected system, the line voltage is equal
to:
A) Phase voltage
B) Phase voltage × √3
C) Phase voltage ÷ √3
D) Phase voltage × 2
Correct ,,,answer,,,,: B
Rationale: Line voltage = phase voltage × √3 (approximately 1.732) due to
120° phase separation .
Q7. What is the primary purpose of a transformer in an electrical
system?
A) Change voltage levels through electromagnetic induction
B) Convert AC to DC
C) Increase conductor flexibility
D) Eliminate grounding requirements
, Correct ,,,answer,,,,: A
Rationale: Transformers use electromagnetic induction between primary
and secondary windings to step voltage up or down .
Q8. A transformer steps down voltage from 480V to 120V. What
happens to current if power remains constant?
A) Decreases
B) Increases
C) Remains the same
D) Becomes zero
Correct ,,,answer,,,,: B
Rationale: With constant power, lowering voltage increases current (P = V
× I) .
Q9. What is the function of a capacitor in an electrical circuit?
A) Store energy in a magnetic field
B) Store energy in an electric field
C) Increase resistance
D) Convert AC to DC
Correct ,,,answer,,,,: B
Rationale: Capacitors store energy in electrostatic fields between
conductive plates .
