ALARM SYSTEMS/SECURITY SYSTEMS
CONTRACTOR LICENSE EXAM 300 ACTUAL
QUESTIONS AND CORRECT ANSWERS WITH
RATIONALE LATEST UPDATE ALREADY GRADED A+
This comprehensive 300-question practice exam is designed for the Alarm
Systems/Security Systems Contractor license, covering intrusion detection, CCTV,
access control, and Virginia-specific regulations. Questions are organized into six
sections: general electrical theory, fire alarm and NEC requirements, burglar alarm
applications, CCTV systems, access control, and state licensing and business law.
Each question includes a correct answer and detailed rationale to reinforce
learning. The content reflects the dual licensing requirements in Virginia, where
the Department of Criminal Justice Services (DCJS) regulates individual
technicians and the Board for Contractors licenses the business entity to contract
for installations.
Section 1: General Knowledge and Electrical Theory (Questions 1-50)
Question 1: What is the primary purpose of a security system in a commercial
building?
A) Reduce energy consumption
B) Protect people and property from threats such as theft, vandalism, or
unauthorized access
C) Enhance the aesthetic appeal of the building
D) Monitor weather conditions for the building management system
Answer: B
Rationale: The fundamental purpose of any security system is to safeguard
occupants and property . This is achieved through detection, deterrence, and
response to security threats, which is the core mission of these systems,
distinguishing them from systems designed for energy management or
environmental monitoring.
,Question 2: According to Ohm's Law, what is the formula for calculating current
(I) given voltage (V) and resistance (R)?
A) I = V + R
B) I = V * R
C) I = V / R
D) I = R / V
Answer: C
Rationale: Ohm's Law is a fundamental principle in electrical theory, stating that
the current through a conductor between two points is directly proportional to the
voltage across the two points and inversely proportional to the resistance. The
formula is I = V / R, where I is current in amperes, V is voltage in volts, and R is
resistance in ohms.
Question 3: Which of the following is considered an active security sensor?
A) Passive infrared (PIR) detector
B) Magnetic door contact
C) Motion-activated camera
D) Pressure-sensitive mat
Answer: C
Rationale: Active sensors emit energy, such as infrared or microwaves, and detect
changes in the reflected or received signal to sense motion . A motion-activated
camera that emits infrared light for night vision is an active sensor. Passive
sensors, like PIR detectors, sense changes in ambient energy (heat) without
emitting their own energy.
Question 4: A security system draws 4 amperes of current and is connected to a 12
V DC power supply. What is the total power consumed by the system?
A) 3 Watts
B) 8 Watts
C) 48 Watts
D) 4 Watts
Answer: C
Rationale: The formula for electrical power is P = V * I, where P is power in watts,
V is voltage, and I is current. Using the values from the question, P = 12 V * 4 A =
48 W.
Question 5: What is the primary advantage of using a dual-technology motion
sensor over a single-technology sensor?
A) Lower cost
B) Higher sensitivity to all types of motion
,C) Reduced false alarms
D) Simpler installation
Answer: C
Rationale: Dual-technology sensors require both technologies (e.g., PIR and
microwave) to detect a presence to trigger an alarm. This feature significantly
reduces false alarms because a single technology (like a PIR detecting heat from a
small animal) will not trigger the alarm unless the second technology also confirms
motion .
Question 6: Which of the following is the correct unit of measurement for
resistance?
A) Volt
B) Ampere
C) Watt
D) Ohm
Answer: D
Rationale: The ohm (symbol Ω) is the SI unit of electrical resistance, named after
the German physicist Georg Simon Ohm. It represents the resistance between two
points of a conductor when a constant potential difference of one volt produces a
current of one ampere.
Question 7: In a series circuit, how is the total voltage drop across all components
related to the source voltage?
A) The sum of voltage drops is less than the source voltage
B) The sum of voltage drops is greater than the source voltage
C) The sum of voltage drops is equal to the source voltage
D) The voltage drop is the same across every component and is equal to the source
voltage
Answer: C
Rationale: Kirchhoff's Voltage Law states that the sum of the voltage drops around
any closed loop in a circuit must equal the total source voltage in that loop. This
means that in a series circuit, the voltage is divided among the components, and the
total of these divided voltages equals the source voltage.
Question 8: What is the typical voltage used for hardwired security sensors?
A) 120 V AC
B) 12 V DC
C) 24 V DC
D) 5 V AC
Answer: C
, Rationale: Hardwired security sensors and their communication circuits typically
operate at 24 V DC . This low voltage is standard for powering devices like door
contacts, PIRs, and glass break sensors, ensuring safety and compatibility with
most control panels.
Question 9: Which of the following best describes a "duress alarm"?
A) A fire alarm that triggers automatically when smoke is detected
B) A silent alarm triggered under a threat or hostage situation
C) An alarm that detects water intrusion in a basement
D) A motion-activated siren designed to deter trespassing
Answer: B
Rationale: A duress alarm (or panic alarm) is designed to be activated by a person
under duress to silently signal for help without alerting the perpetrator . This
allows personnel to discreetly alert authorities in dangerous situations like
robberies or active shooter events.
Question 10: Which type of security system component detects unauthorized entry
by sensing motion within a designated area?
A) Door strike
B) Access control panel
C) Motion detector
D) CCTV camera
Answer: C
Rationale: Motion detectors, such as Passive Infrared (PIR) or microwave sensors,
are specifically designed to sense movement within a defined area and trigger an
alarm or alert to indicate a potential intrusion .
Question 11: A contractor is designing a security system and needs to determine
the power consumption of a camera that operates at 24 V DC and draws 2 A. What
is the power in watts?
A) 12 W
B) 24 W
C) 48 W
D) 72 W
Answer: C
Rationale: Using the power formula P = V * I, the camera consumes 24 V * 2 A =
48 W. Understanding power consumption is critical for correctly sizing power
supplies and battery backup for security systems .
CONTRACTOR LICENSE EXAM 300 ACTUAL
QUESTIONS AND CORRECT ANSWERS WITH
RATIONALE LATEST UPDATE ALREADY GRADED A+
This comprehensive 300-question practice exam is designed for the Alarm
Systems/Security Systems Contractor license, covering intrusion detection, CCTV,
access control, and Virginia-specific regulations. Questions are organized into six
sections: general electrical theory, fire alarm and NEC requirements, burglar alarm
applications, CCTV systems, access control, and state licensing and business law.
Each question includes a correct answer and detailed rationale to reinforce
learning. The content reflects the dual licensing requirements in Virginia, where
the Department of Criminal Justice Services (DCJS) regulates individual
technicians and the Board for Contractors licenses the business entity to contract
for installations.
Section 1: General Knowledge and Electrical Theory (Questions 1-50)
Question 1: What is the primary purpose of a security system in a commercial
building?
A) Reduce energy consumption
B) Protect people and property from threats such as theft, vandalism, or
unauthorized access
C) Enhance the aesthetic appeal of the building
D) Monitor weather conditions for the building management system
Answer: B
Rationale: The fundamental purpose of any security system is to safeguard
occupants and property . This is achieved through detection, deterrence, and
response to security threats, which is the core mission of these systems,
distinguishing them from systems designed for energy management or
environmental monitoring.
,Question 2: According to Ohm's Law, what is the formula for calculating current
(I) given voltage (V) and resistance (R)?
A) I = V + R
B) I = V * R
C) I = V / R
D) I = R / V
Answer: C
Rationale: Ohm's Law is a fundamental principle in electrical theory, stating that
the current through a conductor between two points is directly proportional to the
voltage across the two points and inversely proportional to the resistance. The
formula is I = V / R, where I is current in amperes, V is voltage in volts, and R is
resistance in ohms.
Question 3: Which of the following is considered an active security sensor?
A) Passive infrared (PIR) detector
B) Magnetic door contact
C) Motion-activated camera
D) Pressure-sensitive mat
Answer: C
Rationale: Active sensors emit energy, such as infrared or microwaves, and detect
changes in the reflected or received signal to sense motion . A motion-activated
camera that emits infrared light for night vision is an active sensor. Passive
sensors, like PIR detectors, sense changes in ambient energy (heat) without
emitting their own energy.
Question 4: A security system draws 4 amperes of current and is connected to a 12
V DC power supply. What is the total power consumed by the system?
A) 3 Watts
B) 8 Watts
C) 48 Watts
D) 4 Watts
Answer: C
Rationale: The formula for electrical power is P = V * I, where P is power in watts,
V is voltage, and I is current. Using the values from the question, P = 12 V * 4 A =
48 W.
Question 5: What is the primary advantage of using a dual-technology motion
sensor over a single-technology sensor?
A) Lower cost
B) Higher sensitivity to all types of motion
,C) Reduced false alarms
D) Simpler installation
Answer: C
Rationale: Dual-technology sensors require both technologies (e.g., PIR and
microwave) to detect a presence to trigger an alarm. This feature significantly
reduces false alarms because a single technology (like a PIR detecting heat from a
small animal) will not trigger the alarm unless the second technology also confirms
motion .
Question 6: Which of the following is the correct unit of measurement for
resistance?
A) Volt
B) Ampere
C) Watt
D) Ohm
Answer: D
Rationale: The ohm (symbol Ω) is the SI unit of electrical resistance, named after
the German physicist Georg Simon Ohm. It represents the resistance between two
points of a conductor when a constant potential difference of one volt produces a
current of one ampere.
Question 7: In a series circuit, how is the total voltage drop across all components
related to the source voltage?
A) The sum of voltage drops is less than the source voltage
B) The sum of voltage drops is greater than the source voltage
C) The sum of voltage drops is equal to the source voltage
D) The voltage drop is the same across every component and is equal to the source
voltage
Answer: C
Rationale: Kirchhoff's Voltage Law states that the sum of the voltage drops around
any closed loop in a circuit must equal the total source voltage in that loop. This
means that in a series circuit, the voltage is divided among the components, and the
total of these divided voltages equals the source voltage.
Question 8: What is the typical voltage used for hardwired security sensors?
A) 120 V AC
B) 12 V DC
C) 24 V DC
D) 5 V AC
Answer: C
, Rationale: Hardwired security sensors and their communication circuits typically
operate at 24 V DC . This low voltage is standard for powering devices like door
contacts, PIRs, and glass break sensors, ensuring safety and compatibility with
most control panels.
Question 9: Which of the following best describes a "duress alarm"?
A) A fire alarm that triggers automatically when smoke is detected
B) A silent alarm triggered under a threat or hostage situation
C) An alarm that detects water intrusion in a basement
D) A motion-activated siren designed to deter trespassing
Answer: B
Rationale: A duress alarm (or panic alarm) is designed to be activated by a person
under duress to silently signal for help without alerting the perpetrator . This
allows personnel to discreetly alert authorities in dangerous situations like
robberies or active shooter events.
Question 10: Which type of security system component detects unauthorized entry
by sensing motion within a designated area?
A) Door strike
B) Access control panel
C) Motion detector
D) CCTV camera
Answer: C
Rationale: Motion detectors, such as Passive Infrared (PIR) or microwave sensors,
are specifically designed to sense movement within a defined area and trigger an
alarm or alert to indicate a potential intrusion .
Question 11: A contractor is designing a security system and needs to determine
the power consumption of a camera that operates at 24 V DC and draws 2 A. What
is the power in watts?
A) 12 W
B) 24 W
C) 48 W
D) 72 W
Answer: C
Rationale: Using the power formula P = V * I, the camera consumes 24 V * 2 A =
48 W. Understanding power consumption is critical for correctly sizing power
supplies and battery backup for security systems .
