NYC DCAS ELECTRICIAN EXAM – (160 QUESTIONS)
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Q1. Ohm’s Law is mathematically expressed as:
A) P = V × I
B) V = I × R
C) I = P × R
D) V = P / I
Correct answer: B
Rationale: Ohm’s Law states that Voltage (V) equals Current (I) multiplied by
Resistance (R).
Q2. A 240V single-phase load draws 18A. What is the power consumption?
A) 2.16 kW
B) 4.32 kW
C) 5.10 kW
D) 3.60 kW
Correct answer: B (4.32 kW)
Rationale: P = V × I = 240V × 18A = 4320W = 4.32 kW.
Q3. What is the total equivalent resistance of three 15-ohm resistors connected in
parallel?
A) 5 ohms
B) 15 ohms
C) 45 ohms
D) 60 ohms
Correct answer: A (5 ohms)
Rationale: For identical resistors in parallel: R_total = R/n = 15Ω/3 = 5Ω.
Q4. The unit of electrical resistance is the:
A) Volt
B) Ampere
,C) Ohm
D) Watt
Correct answer: C (Ohm)
Rationale: The Ohm (Ω) is the SI unit of electrical resistance.
Q5. In a DC circuit, current flows:
A) Alternating direction
B) Only in one direction
C) Randomly
D) Only in transformers
Correct answer: B (Only in one direction)
Rationale: Direct Current (DC) is characterized by a unidirectional flow of electric
charge.
Q6. A 60Hz AC system means the current changes direction how many times per
second?
A) 60 times
B) 120 times
C) 30 times
D) 100 times
Correct answer: B (120 times)
Rationale: 60 Hz = 60 cycles per second; each cycle has two direction changes →
120 changes/second.
Q7. The function of a capacitor is to:
A) Store magnetic energy
B) Store electrical charge
C) Increase resistance
D) Reduce voltage permanently
Correct answer: B (Store electrical charge)
Rationale: A capacitor stores electrical energy in an electrostatic field.
Q8. Which type of current is produced by a battery?
A) Alternating Current
B) Direct Current
C) Pulsating DC
D) Inductive Current
,Correct answer: B (Direct Current)
Rationale: Batteries produce DC voltage with constant polarity.
Q9. A transformer works on the principle of:
A) Static electricity
B) Chemical reaction
C) Electromagnetic induction
D) Mechanical force
Correct answer: C (Electromagnetic induction)
Rationale: Transformers transfer energy between circuits via mutual inductance.
Q10. A step-down transformer:
A) Increases voltage
B) Reduces voltage
C) Increases frequency
D) Converts AC to DC
Correct answer: B (Reduces voltage)
Rationale: Step-down transformer has fewer secondary turns, producing lower
secondary voltage.
Q11. The power factor of an AC circuit is the ratio of:
A) Voltage to Current
B) Resistance to Impedance
C) True Power to Apparent Power
D) Inductance to Capacitance
Correct answer: C (True Power to Apparent Power)
Rationale: Power factor (PF) indicates how effectively power is converted into
useful work.
Q12. A resistor with color bands: red, red, orange, gold has a nominal resistance
of:
A) 22 Ω
B) 220 Ω
C) 2.2 kΩ
D) 22 kΩ
, Correct answer: D (22 kΩ)
Rationale: Red=2, Red=2, Orange=×1000 → 22,000Ω = 22kΩ, gold = ±5%
tolerance.
Q13. The voltage drop across a 10Ω resistor carrying 2A is:
A) 5V
B) 10V
C) 20V
D) 0.5V
Correct answer: C (20V)
Rationale: V = I × R = 2A × 10Ω = 20V.
Q14. The NEC (National Electrical Code) is published by:
A) ANSI
B) IEEE
C) NFPA
D) OSHA
Correct answer: C (NFPA)
Rationale: NEC (NFPA 70) is published by the National Fire Protection
Association.
Q15. The minimum size equipment grounding conductor for a 20A branch circuit
is:
A) 14 AWG
B) 12 AWG
C) 10 AWG
D) 8 AWG
Correct answer: B (12 AWG)
Rationale: NEC Table 250.122 requires a 12 AWG copper EGC for a 20A
overcurrent device.
Q16. A three-phase wye-connected system has a line voltage of 480V. The phase
voltage is approximately:
A) 120V
B) 208V
C) 277V
D) 480V
UP-TO-DATE ACTUAL EXAM QUESTIONS AND 100%
ACCURATE SOLUTIONS | VERIFIED ANSWERS –
INSTANT PDF DOWNLOAD
Q1. Ohm’s Law is mathematically expressed as:
A) P = V × I
B) V = I × R
C) I = P × R
D) V = P / I
Correct answer: B
Rationale: Ohm’s Law states that Voltage (V) equals Current (I) multiplied by
Resistance (R).
Q2. A 240V single-phase load draws 18A. What is the power consumption?
A) 2.16 kW
B) 4.32 kW
C) 5.10 kW
D) 3.60 kW
Correct answer: B (4.32 kW)
Rationale: P = V × I = 240V × 18A = 4320W = 4.32 kW.
Q3. What is the total equivalent resistance of three 15-ohm resistors connected in
parallel?
A) 5 ohms
B) 15 ohms
C) 45 ohms
D) 60 ohms
Correct answer: A (5 ohms)
Rationale: For identical resistors in parallel: R_total = R/n = 15Ω/3 = 5Ω.
Q4. The unit of electrical resistance is the:
A) Volt
B) Ampere
,C) Ohm
D) Watt
Correct answer: C (Ohm)
Rationale: The Ohm (Ω) is the SI unit of electrical resistance.
Q5. In a DC circuit, current flows:
A) Alternating direction
B) Only in one direction
C) Randomly
D) Only in transformers
Correct answer: B (Only in one direction)
Rationale: Direct Current (DC) is characterized by a unidirectional flow of electric
charge.
Q6. A 60Hz AC system means the current changes direction how many times per
second?
A) 60 times
B) 120 times
C) 30 times
D) 100 times
Correct answer: B (120 times)
Rationale: 60 Hz = 60 cycles per second; each cycle has two direction changes →
120 changes/second.
Q7. The function of a capacitor is to:
A) Store magnetic energy
B) Store electrical charge
C) Increase resistance
D) Reduce voltage permanently
Correct answer: B (Store electrical charge)
Rationale: A capacitor stores electrical energy in an electrostatic field.
Q8. Which type of current is produced by a battery?
A) Alternating Current
B) Direct Current
C) Pulsating DC
D) Inductive Current
,Correct answer: B (Direct Current)
Rationale: Batteries produce DC voltage with constant polarity.
Q9. A transformer works on the principle of:
A) Static electricity
B) Chemical reaction
C) Electromagnetic induction
D) Mechanical force
Correct answer: C (Electromagnetic induction)
Rationale: Transformers transfer energy between circuits via mutual inductance.
Q10. A step-down transformer:
A) Increases voltage
B) Reduces voltage
C) Increases frequency
D) Converts AC to DC
Correct answer: B (Reduces voltage)
Rationale: Step-down transformer has fewer secondary turns, producing lower
secondary voltage.
Q11. The power factor of an AC circuit is the ratio of:
A) Voltage to Current
B) Resistance to Impedance
C) True Power to Apparent Power
D) Inductance to Capacitance
Correct answer: C (True Power to Apparent Power)
Rationale: Power factor (PF) indicates how effectively power is converted into
useful work.
Q12. A resistor with color bands: red, red, orange, gold has a nominal resistance
of:
A) 22 Ω
B) 220 Ω
C) 2.2 kΩ
D) 22 kΩ
, Correct answer: D (22 kΩ)
Rationale: Red=2, Red=2, Orange=×1000 → 22,000Ω = 22kΩ, gold = ±5%
tolerance.
Q13. The voltage drop across a 10Ω resistor carrying 2A is:
A) 5V
B) 10V
C) 20V
D) 0.5V
Correct answer: C (20V)
Rationale: V = I × R = 2A × 10Ω = 20V.
Q14. The NEC (National Electrical Code) is published by:
A) ANSI
B) IEEE
C) NFPA
D) OSHA
Correct answer: C (NFPA)
Rationale: NEC (NFPA 70) is published by the National Fire Protection
Association.
Q15. The minimum size equipment grounding conductor for a 20A branch circuit
is:
A) 14 AWG
B) 12 AWG
C) 10 AWG
D) 8 AWG
Correct answer: B (12 AWG)
Rationale: NEC Table 250.122 requires a 12 AWG copper EGC for a 20A
overcurrent device.
Q16. A three-phase wye-connected system has a line voltage of 480V. The phase
voltage is approximately:
A) 120V
B) 208V
C) 277V
D) 480V
