Virginia Solar Installer Exam Practice
Questions & [Verified Answers], Plus
Explained Rationales|2026 Latest Update|
Instant Download PDF
1. What is the primary function of a photovoltaic (PV) module in a
solar electric system?
A. Convert AC electricity into DC electricity
B. Store electrical energy for nighttime use
C. Convert sunlight into direct-current electrical energy
D. Increase utility voltage automatically
Answer: C. Convert sunlight into direct-current electrical energy
Rationale: A PV module uses semiconductor cells to convert incoming
solar radiation into direct-current (DC) electricity through the
photovoltaic effect. Batteries store energy, while inverters generally
convert DC to AC.
2. Which component converts the DC electricity produced by a PV
array into AC electricity suitable for typical building loads?
A. Combiner box
B. Inverter
C. Disconnect switch
D. Charge controller
Answer: B. Inverter
Rationale: The inverter converts DC power from the PV array into
alternating-current (AC) power. In grid-connected systems, the
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,inverter also synchronizes its output with the utility's voltage and
frequency and incorporates required protection functions.
3. In a grid-connected residential PV system, what is the primary
purpose of rapid shutdown equipment?
A. Increase PV module efficiency
B. Reduce the temperature of PV modules
C. Reduce shock hazards by rapidly controlling PV circuit voltage or
current during an emergency
D. Prevent batteries from overcharging
Answer: C. Reduce shock hazards by rapidly controlling PV circuit
voltage or current during an emergency
Rationale: Rapid shutdown requirements are intended to reduce
electrical hazards for firefighters and other emergency personnel. The
system must be designed so that specified portions of the PV wiring
can be brought to a safer electrical condition when rapid shutdown is
initiated.
4. Which factor generally has the greatest direct effect on the
current produced by a PV module under normal operating
conditions?
A. Solar irradiance
B. Conduit color
C. Junction-box location
D. AC frequency
Answer: A. Solar irradiance
Rationale: PV current is strongly related to the amount of sunlight
striking the cells. Increasing irradiance generally increases current,
while temperature has a stronger influence on PV voltage.
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, 5. Why are PV modules commonly connected in series to form a
string?
A. To increase system voltage
B. To eliminate the need for an inverter
C. To convert DC to AC
D. To prevent all shading losses
Answer: A. To increase system voltage
Rationale: Connecting modules in series increases voltage while the
string current remains approximately equal to the current of an
individual module. Higher DC voltage can reduce current for a given
power level, which can help with conductor sizing and system
efficiency.
6. What happens to the voltage of series-connected PV modules?
A. The module voltages add together
B. The module voltages cancel each other
C. Voltage always remains equal to one module
D. Voltage becomes zero when sunlight increases
Answer: A. The module voltages add together
Rationale: In a series circuit, the individual voltage contributions add.
For example, three modules with approximately 40 V operating
voltage each would produce approximately 120 V under comparable
operating conditions.
7. What happens to current when identical PV strings are connected
in parallel?
A. The voltages add while current remains unchanged
B. The currents add while voltage remains approximately the same
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, C. Both voltage and current become zero
D. Current is always divided by the number of strings
Answer: B. The currents add while voltage remains approximately the
same
Rationale: Parallel circuits maintain approximately the same voltage
while the available current from identical strings adds. This is one
reason arrays can be expanded by connecting multiple strings in
parallel.
8. A PV module has an open-circuit voltage (Voc) of 45 V. Four
identical modules are connected in series. Ignoring temperature
effects, what is the approximate open-circuit voltage of the
string?
A. 11.25 V
B. 45 V
C. 90 V
D. 180 V
Answer: D. 180 V
Rationale: Series-connected voltage sources add. Therefore, 45 V × 4 =
180 V. Actual design calculations must also account for temperature
effects when determining the maximum possible PV voltage.
9. Why must the cold-temperature voltage of a PV array be
considered during design?
A. PV voltage can increase at lower temperatures
B. PV current always becomes zero in cold weather
C. Inverters operate only when modules are hot
D. Cold weather eliminates grounding requirements
Answer: A. PV voltage can increase at lower temperatures
4|Page
Questions & [Verified Answers], Plus
Explained Rationales|2026 Latest Update|
Instant Download PDF
1. What is the primary function of a photovoltaic (PV) module in a
solar electric system?
A. Convert AC electricity into DC electricity
B. Store electrical energy for nighttime use
C. Convert sunlight into direct-current electrical energy
D. Increase utility voltage automatically
Answer: C. Convert sunlight into direct-current electrical energy
Rationale: A PV module uses semiconductor cells to convert incoming
solar radiation into direct-current (DC) electricity through the
photovoltaic effect. Batteries store energy, while inverters generally
convert DC to AC.
2. Which component converts the DC electricity produced by a PV
array into AC electricity suitable for typical building loads?
A. Combiner box
B. Inverter
C. Disconnect switch
D. Charge controller
Answer: B. Inverter
Rationale: The inverter converts DC power from the PV array into
alternating-current (AC) power. In grid-connected systems, the
1|Page
,inverter also synchronizes its output with the utility's voltage and
frequency and incorporates required protection functions.
3. In a grid-connected residential PV system, what is the primary
purpose of rapid shutdown equipment?
A. Increase PV module efficiency
B. Reduce the temperature of PV modules
C. Reduce shock hazards by rapidly controlling PV circuit voltage or
current during an emergency
D. Prevent batteries from overcharging
Answer: C. Reduce shock hazards by rapidly controlling PV circuit
voltage or current during an emergency
Rationale: Rapid shutdown requirements are intended to reduce
electrical hazards for firefighters and other emergency personnel. The
system must be designed so that specified portions of the PV wiring
can be brought to a safer electrical condition when rapid shutdown is
initiated.
4. Which factor generally has the greatest direct effect on the
current produced by a PV module under normal operating
conditions?
A. Solar irradiance
B. Conduit color
C. Junction-box location
D. AC frequency
Answer: A. Solar irradiance
Rationale: PV current is strongly related to the amount of sunlight
striking the cells. Increasing irradiance generally increases current,
while temperature has a stronger influence on PV voltage.
2|Page
, 5. Why are PV modules commonly connected in series to form a
string?
A. To increase system voltage
B. To eliminate the need for an inverter
C. To convert DC to AC
D. To prevent all shading losses
Answer: A. To increase system voltage
Rationale: Connecting modules in series increases voltage while the
string current remains approximately equal to the current of an
individual module. Higher DC voltage can reduce current for a given
power level, which can help with conductor sizing and system
efficiency.
6. What happens to the voltage of series-connected PV modules?
A. The module voltages add together
B. The module voltages cancel each other
C. Voltage always remains equal to one module
D. Voltage becomes zero when sunlight increases
Answer: A. The module voltages add together
Rationale: In a series circuit, the individual voltage contributions add.
For example, three modules with approximately 40 V operating
voltage each would produce approximately 120 V under comparable
operating conditions.
7. What happens to current when identical PV strings are connected
in parallel?
A. The voltages add while current remains unchanged
B. The currents add while voltage remains approximately the same
3|Page
, C. Both voltage and current become zero
D. Current is always divided by the number of strings
Answer: B. The currents add while voltage remains approximately the
same
Rationale: Parallel circuits maintain approximately the same voltage
while the available current from identical strings adds. This is one
reason arrays can be expanded by connecting multiple strings in
parallel.
8. A PV module has an open-circuit voltage (Voc) of 45 V. Four
identical modules are connected in series. Ignoring temperature
effects, what is the approximate open-circuit voltage of the
string?
A. 11.25 V
B. 45 V
C. 90 V
D. 180 V
Answer: D. 180 V
Rationale: Series-connected voltage sources add. Therefore, 45 V × 4 =
180 V. Actual design calculations must also account for temperature
effects when determining the maximum possible PV voltage.
9. Why must the cold-temperature voltage of a PV array be
considered during design?
A. PV voltage can increase at lower temperatures
B. PV current always becomes zero in cold weather
C. Inverters operate only when modules are hot
D. Cold weather eliminates grounding requirements
Answer: A. PV voltage can increase at lower temperatures
4|Page
