NYC DCAS ELECTRICIAN PRACTICE
EXAM 2 Questions and Answers with
Rationales Latest Versions
Question 1
A 120-volt circuit supplies a 1,440-watt resistive load. What is the approximate current?
A. 8 A
B. 10 A
C. 12 A
D. 15 A
Correct Answer: B. 12 A
Rationale:
Use:
[
I=\frac{P}{V}
]
[
I=\frac{1440}{120}=12A
]
Therefore, the load draws 12 amperes.
Question 2
Three resistors of 4 Ω, 6 Ω, and 10 Ω are connected in series. What is their total resistance?
A. 10 Ω
B. 16 Ω
C. 20 Ω
D. 24 Ω
Correct Answer: C. 20 Ω
Rationale:
For series resistors:
,[
R_T=R_1+R_2+R_3
]
[
R_T=4+6+10=20\Omega
]
The total resistance is 20 ohms.
Question 3
A 120-volt source is connected to a 40-ohm resistor. What current flows?
A. 2 A
B. 3 A
C. 4 A
D. 6 A
Correct Answer: B. 3 A
Rationale:
[
I=\frac{V}{R}
]
[
I=\frac{120}{40}=3A
]
Therefore, the current is 3 amperes.
Question 4
Which statement correctly describes a parallel circuit?
A. The same current must flow through every branch
B. Each branch is connected across the same two voltage points
C. There is only one possible path for current
D. Total resistance always increases when another branch is added
,Correct Answer: B. Each branch is connected across the same two voltage points
Rationale:
In a parallel circuit, each branch is connected across the source. Therefore, the voltage across the
branches is generally the same, while branch currents depend on their respective impedances.
Adding another parallel branch generally decreases total circuit resistance.
Question 5
What is the primary purpose of an overcurrent protective device?
A. To protect conductors and equipment from excessive current
B. To increase circuit voltage
C. To improve lighting color
D. To increase motor horsepower
Correct Answer: A. To protect conductors and equipment from excessive current
Rationale:
Fuses and circuit breakers are designed to interrupt circuits under specified overcurrent
conditions. Proper overcurrent protection helps prevent conductor overheating and associated
fire and equipment hazards.
Question 6
A circuit breaker trips immediately after being reset. What should the electrician do?
A. Keep resetting it until it remains closed
B. Replace it with a larger breaker immediately
C. Investigate for a short circuit, ground fault, or other abnormal condition
D. Remove the equipment grounding conductor
Correct Answer: C. Investigate for a short circuit, ground fault, or other abnormal
condition
Rationale:
Immediate tripping is a warning that an abnormal condition may exist. Repeatedly resetting a
breaker can be dangerous.
The electrician should safely isolate the circuit and determine the cause before restoring power.
, Question 7
What is the primary function of an equipment grounding conductor?
A. Carry normal load current
B. Provide an effective fault-current path
C. Increase circuit voltage
D. Reduce motor speed
Correct Answer: B. Provide an effective fault-current path
Rationale:
The equipment grounding conductor normally carries no load current. During a fault involving
conductive equipment, it provides a path intended to facilitate operation of the overcurrent
protective device.
Question 8
What is the primary purpose of bonding metal electrical enclosures?
A. To increase their resistance
B. To establish electrical continuity and an effective fault-current path
C. To increase the supply voltage
D. To reduce conductor ampacity
Correct Answer: B. To establish electrical continuity and an effective fault-current path
Rationale:
Bonding connects conductive parts together so that, under fault conditions, a reliable path exists
for fault current.
This helps protective devices operate and reduces the risk that exposed metal remains energized.
Question 9
An electrician is about to work on a circuit that has supposedly been de-energized. What should
happen before touching the conductors?
A. Assume the breaker label is correct
B. Verify absence of voltage using an appropriate test instrument
EXAM 2 Questions and Answers with
Rationales Latest Versions
Question 1
A 120-volt circuit supplies a 1,440-watt resistive load. What is the approximate current?
A. 8 A
B. 10 A
C. 12 A
D. 15 A
Correct Answer: B. 12 A
Rationale:
Use:
[
I=\frac{P}{V}
]
[
I=\frac{1440}{120}=12A
]
Therefore, the load draws 12 amperes.
Question 2
Three resistors of 4 Ω, 6 Ω, and 10 Ω are connected in series. What is their total resistance?
A. 10 Ω
B. 16 Ω
C. 20 Ω
D. 24 Ω
Correct Answer: C. 20 Ω
Rationale:
For series resistors:
,[
R_T=R_1+R_2+R_3
]
[
R_T=4+6+10=20\Omega
]
The total resistance is 20 ohms.
Question 3
A 120-volt source is connected to a 40-ohm resistor. What current flows?
A. 2 A
B. 3 A
C. 4 A
D. 6 A
Correct Answer: B. 3 A
Rationale:
[
I=\frac{V}{R}
]
[
I=\frac{120}{40}=3A
]
Therefore, the current is 3 amperes.
Question 4
Which statement correctly describes a parallel circuit?
A. The same current must flow through every branch
B. Each branch is connected across the same two voltage points
C. There is only one possible path for current
D. Total resistance always increases when another branch is added
,Correct Answer: B. Each branch is connected across the same two voltage points
Rationale:
In a parallel circuit, each branch is connected across the source. Therefore, the voltage across the
branches is generally the same, while branch currents depend on their respective impedances.
Adding another parallel branch generally decreases total circuit resistance.
Question 5
What is the primary purpose of an overcurrent protective device?
A. To protect conductors and equipment from excessive current
B. To increase circuit voltage
C. To improve lighting color
D. To increase motor horsepower
Correct Answer: A. To protect conductors and equipment from excessive current
Rationale:
Fuses and circuit breakers are designed to interrupt circuits under specified overcurrent
conditions. Proper overcurrent protection helps prevent conductor overheating and associated
fire and equipment hazards.
Question 6
A circuit breaker trips immediately after being reset. What should the electrician do?
A. Keep resetting it until it remains closed
B. Replace it with a larger breaker immediately
C. Investigate for a short circuit, ground fault, or other abnormal condition
D. Remove the equipment grounding conductor
Correct Answer: C. Investigate for a short circuit, ground fault, or other abnormal
condition
Rationale:
Immediate tripping is a warning that an abnormal condition may exist. Repeatedly resetting a
breaker can be dangerous.
The electrician should safely isolate the circuit and determine the cause before restoring power.
, Question 7
What is the primary function of an equipment grounding conductor?
A. Carry normal load current
B. Provide an effective fault-current path
C. Increase circuit voltage
D. Reduce motor speed
Correct Answer: B. Provide an effective fault-current path
Rationale:
The equipment grounding conductor normally carries no load current. During a fault involving
conductive equipment, it provides a path intended to facilitate operation of the overcurrent
protective device.
Question 8
What is the primary purpose of bonding metal electrical enclosures?
A. To increase their resistance
B. To establish electrical continuity and an effective fault-current path
C. To increase the supply voltage
D. To reduce conductor ampacity
Correct Answer: B. To establish electrical continuity and an effective fault-current path
Rationale:
Bonding connects conductive parts together so that, under fault conditions, a reliable path exists
for fault current.
This helps protective devices operate and reduces the risk that exposed metal remains energized.
Question 9
An electrician is about to work on a circuit that has supposedly been de-energized. What should
happen before touching the conductors?
A. Assume the breaker label is correct
B. Verify absence of voltage using an appropriate test instrument
