Q.1 Which of the following is the most effective method to reduce standby power consumption in household appliances?
Using larger power cords
Unplugging devices or using smart power strips
Increasing the voltage supply
Installing a higher capacity fuse
Explanation - Smart power strips can cut off power to devices when they are not in use, eliminating standby power draw.
Correct answer is: Unplugging devices or using smart power strips
Q.2 What is the primary advantage of using LED lighting over incandescent bulbs?
Higher luminous intensity for the same power
Lower cost per unit
Longer lifespan and higher energy efficiency
Ability to emit ultraviolet light
Explanation - LEDs consume less power for the same light output and last significantly longer than incandescent lamps.
Correct answer is: Longer lifespan and higher energy efficiency
Q.3 In a building HVAC system, which technique helps recover waste heat from exhaust air?
Variable Air Volume (VAV) control
Heat recovery ventilator (HRV)
Constant Air Volume (CAV) system
Direct expansion cooling
Explanation - HRVs transfer heat from outgoing stale air to incoming fresh air, reducing heating load.
Correct answer is: Heat recovery ventilator (HRV)
Q.4 Which type of transformer is most suitable for reducing iron losses in a power distribution network?
Core‑type transformer with laminated steel
Toroidal transformer with solid iron core
Dry‑type transformer with epoxy resin
Auto‑transformer with copper windings
Explanation - Laminated steel cores reduce eddy current losses, which are a major component of iron losses.
Correct answer is: Core‑type transformer with laminated steel
Q.5 What is the main purpose of installing a programmable thermostat in a residential building?
To increase the heating temperature automatically
To schedule heating/cooling cycles for optimal energy use
To provide backup power during outages
To monitor water consumption
Explanation - Programmable thermostats allow users to set temperature set‑points based on occupancy, reducing unnecessary heating or cooling.
Correct answer is: To schedule heating/cooling cycles for optimal energy use
Q.6 Which of the following best describes the principle of demand‑side management (DSM)?
Increasing generation capacity at power plants
Shifting or reducing electricity use by consumers during peak periods
Building more transmission lines
Storing excess energy in batteries
Explanation - DSM focuses on influencing consumer behavior or equipment to lower peak demand and overall consumption.
Correct answer is: Shifting or reducing electricity use by consumers during peak periods
Q.7 Which device is used to measure the real power consumed by an AC load?
Wattmeter
Voltmeter
Ammeter
Oscilloscope
Explanation - A wattmeter directly measures real (active) power in watts for AC circuits.
Correct answer is: Wattmeter
Q.8 What is the most common method to improve the power factor of an industrial motor load?
Installing larger circuit breakers
Adding capacitor banks
Increasing line voltage
Reducing motor speed
Explanation - Capacitors supply leading reactive power, compensating for lagging current drawn by inductive loads, thus improving power factor.
Correct answer is: Adding capacitor banks
Q.9 Which of the following renewable energy technologies directly converts solar radiation into electricity?
Solar thermal collector
Photovoltaic (PV) panel
Concentrated solar power (CSP)
Solar water heater
Explanation - PV cells use the photovoltaic effect to convert sunlight directly into electrical energy.
Correct answer is: Photovoltaic (PV) panel
Q.10 In an office building, replacing old fluorescent tubes with modern LED tubes primarily saves energy because:
LED tubes emit more heat
LED tubes have higher luminous efficacy
LED tubes require higher voltage
LED tubes have lower color rendering index
Explanation - Higher luminous efficacy means more light output per watt, reducing overall electricity consumption.
Correct answer is: LED tubes have higher luminous efficacy
Q.11 What is the purpose of a Variable Frequency Drive (VFD) on an induction motor?
To increase motor speed beyond its rated speed
To control motor speed and torque, saving energy
To convert DC to AC power
To provide backup power
Explanation - VFDs adjust supply frequency, allowing the motor to run only as fast as needed, reducing unnecessary energy use.
Correct answer is: To control motor speed and torque, saving energy
Q.12 Which method of building insulation offers the highest R‑value per inch of thickness?
Fiberglass batts
Cellulose blown‑in insulation
Aerogel panels
Expanded polystyrene (EPS) foam
Explanation - Aerogels have extremely low thermal conductivity, providing the highest thermal resistance per unit thickness.
Correct answer is: Aerogel panels
Q.13 In power system operation, the term "load shedding" refers to:
Increasing generation capacity
Deliberately disconnecting some loads to maintain system stability
Installing larger transformers
Improving power factor
Explanation - Load shedding is a controlled outage to prevent a total system collapse during peak demand or emergencies.
Correct answer is: Deliberately disconnecting some loads to maintain system stability
Q.14 Which of the following is a passive solar design strategy?
Installing photovoltaic panels
Using solar water heaters
Orienting windows to maximize winter sunlight gain
Adding a solar tracking system
Explanation - Passive solar design uses building orientation and materials to capture and store solar heat without active devices.
Correct answer is: Orienting windows to maximize winter sunlight gain
Q.15 What is the typical efficiency range of modern electric motor drives when operating at partial loads?
70‑80%
80‑90%
90‑95%
95‑99%
Explanation - Variable speed drives maintain high efficiencies (90‑95%) even at part‑load conditions, unlike fixed‑speed motors.
Correct answer is: 90‑95%
Q.16 Which of the following energy conservation measures can reduce water heating energy consumption the most in a typical household?
Insulating hot water pipes
Using a low‑flow showerhead
Installing a solar water heater
Lowering thermostat temperature by 5 °C
Explanation - Solar water heaters use free solar energy, cutting conventional electricity or gas usage for water heating dramatically.
Correct answer is: Installing a solar water heater
Q.17 What is the main benefit of implementing a building energy management system (BEMS)?
Increasing the building’s height
Automating control of HVAC, lighting, and other loads for optimal efficiency
Providing Wi‑Fi connectivity
Reducing the number of occupants
Explanation - BEMS monitors and controls building systems in real time to minimize energy waste.
Correct answer is: Automating control of HVAC, lighting, and other loads for optimal efficiency
Q.18 Which factor most directly influences the annual energy consumption of an air‑conditioner?
The size of the compressor motor
The Seasonal Energy Efficiency Ratio (SEER)
The color of the unit’s housing
The type of refrigerant used
Explanation - SEER measures cooling efficiency over a typical cooling season; higher SEER means lower energy use.
Correct answer is: The Seasonal Energy Efficiency Ratio (SEER)
Q.19 Which of the following statements about combined heat and power (CHP) systems is true?
CHP systems generate electricity only, without heat.
CHP systems increase overall fuel efficiency by utilizing waste heat.
CHP systems are only applicable to large industrial plants.
CHP systems require renewable fuels.
Explanation - CHP captures waste heat from electricity generation for heating, raising total system efficiency.
Correct answer is: CHP systems increase overall fuel efficiency by utilizing waste heat.
Q.20 What is the primary purpose of using low‑emissivity (low‑E) glass in windows?
To increase the amount of solar gain
To reduce heat loss in winter and heat gain in summer
To make the glass stronger
To lower the cost of the window
Explanation - Low‑E coatings reflect infrared radiation, improving thermal performance of glazing.
Correct answer is: To reduce heat loss in winter and heat gain in summer
Q.21 Which of the following best describes the concept of "energy auditing"?
Designing a new power plant
Measuring and analyzing energy use in a facility to identify savings opportunities
Installing solar panels on rooftops
Increasing the voltage of the supply line
Explanation - Energy audits assess consumption patterns and recommend actions to improve efficiency.
Correct answer is: Measuring and analyzing energy use in a facility to identify savings opportunities
Q.22 In a three‑phase induction motor, the most common method to reduce no‑load losses is:
Using a larger rotor
Improving core material and laminations
Increasing supply voltage
Adding more windings
Explanation - Better core materials and thinner laminations reduce core (iron) losses at no‑load conditions.
Correct answer is: Improving core material and laminations
Q.23 Which of the following devices is used to store electrical energy for later use in a power grid?
Transformer
Capacitor bank
Battery energy storage system
Rectifier
Explanation - Batteries can store excess generation and release it when demand peaks, aiding grid stability.
Correct answer is: Battery energy storage system
Q.24 What does the term "baseload" refer to in electricity generation?
The maximum demand during a day
The minimum level of continuous power that must be supplied
The power generated only during peak hours
The power used by lighting systems
Explanation - Baseload is the constant minimum demand that must be met at all times.
Correct answer is: The minimum level of continuous power that must be supplied
Q.25 Which of the following is a key advantage of using a heat pump for space heating?
It can produce heat at temperatures above 100 °C without electricity
It transfers heat from a colder source to a warmer space, achieving >100% efficiency
It requires no refrigerant
It works only in warm climates
Explanation - Heat pumps move existing heat rather than generating it, giving a coefficient of performance (COP) greater than 1.
Correct answer is: It transfers heat from a colder source to a warmer space, achieving >100% efficiency
Q.26 In the context of lighting, what does the term "lumens per watt" (lm/W) indicate?
The amount of heat produced per watt
The total power consumption of a lamp
The efficiency of a light source in converting electrical power to visible light
The voltage rating of the lamp
Explanation - Higher lm/W values mean more light output for each watt of electrical input.
Correct answer is: The efficiency of a light source in converting electrical power to visible light
Q.27 Which energy conservation strategy is most effective for large commercial refrigeration systems?
Increasing the thermostat set‑point by 10 °C
Using variable speed compressors
Replacing door gaskets with wood
Operating the system 24 hours a day
Explanation - Variable speed compressors adjust capacity to match load, reducing wasteful cycling and energy use.
Correct answer is: Using variable speed compressors
Q.28 What is the main purpose of a "smart grid"?
To increase the physical size of power lines
To enable two‑way communication and automated control for efficient energy distribution
To replace all fossil‑fuel plants with nuclear plants
To eliminate the need for electricity meters
Explanation - Smart grids use ICT to monitor and manage electricity flow, integrating renewables and improving reliability.
Correct answer is: To enable two‑way communication and automated control for efficient energy distribution
Q.29 Which of the following best explains why “night‑time ventilation” can save energy in temperate climates?
It increases solar gain during the day
It uses cooler night air to pre‑cool the building, reducing daytime cooling load
It eliminates the need for heating
It allows the building to operate without electricity
Explanation - Ventilating with cool night air reduces indoor temperature, so less mechanical cooling is needed later.
Correct answer is: It uses cooler night air to pre‑cool the building, reducing daytime cooling load
Q.30 In a three‑phase power system, the method that balances loads to reduce neutral current is called:
Phase shifting
Load balancing
Harmonic filtering
Voltage regulation
Explanation - Balancing the three phases minimizes neutral current, reducing losses and improving system stability.
Correct answer is: Load balancing
Q.31 Which of the following measures directly reduces transmission losses in an electrical grid?
Increasing the length of transmission lines
Using higher transmission voltages
Reducing the number of substations
Operating at lower frequencies
Explanation - Higher voltages lower current for the same power, thus reducing I²R losses in conductors.
Correct answer is: Using higher transmission voltages
Q.32 What is the most common cause of "phantom load" in office equipment?
Over‑voltage conditions
Devices drawing power while switched off or in standby mode
Improper grounding
Excessive cable length
Explanation - Phantom loads are the small amounts of power consumed by equipment when not actively in use.
Correct answer is: Devices drawing power while switched off or in standby mode
Q.33 Which renewable energy source can be most effectively integrated with a battery storage system for peak‑shaving?
Wind power
Solar photovoltaic
Geothermal
Hydropower
Explanation - Solar PV generation is intermittent and often peaks during daytime; batteries store excess for use during peak demand periods.
Correct answer is: Solar photovoltaic
Q.34 In the context of energy conservation, what does the term "retrofit" mean?
Replacing an existing system with a newer, more efficient one
Building a new power plant
Increasing the size of a transformer
Installing more lighting fixtures
Explanation - Retrofits upgrade existing equipment or building elements to improve efficiency.
Correct answer is: Replacing an existing system with a newer, more efficient one
Q.35 Which of the following is a benefit of using a DC microgrid in a campus setting?
Higher conversion losses
Simplified integration of solar PV and battery storage
Increased need for transformers
Limited compatibility with LED lighting
Explanation - DC microgrids avoid multiple AC‑DC conversions, improving overall efficiency when solar PV and LEDs are prevalent.
Correct answer is: Simplified integration of solar PV and battery storage
Q.36 What is the typical efficiency range of modern residential heat‑pump water heaters?
70‑80%
80‑90%
90‑120% (COP 3‑4)
120‑150% (COP 5‑6)
Explanation - Heat‑pump water heaters have COP values of about 3‑4, meaning they deliver 3‑4 units of heat per unit of electricity.
Correct answer is: 90‑120% (COP 3‑4)
Q.37 Which of the following actions has the greatest impact on reducing electricity consumption in data centers?
Installing brighter ceiling lights
Upgrading to high‑efficiency power supplies and servers
Increasing the number of cooling fans
Adding more storage racks
Explanation - Modern IT equipment consumes less power per compute unit, significantly lowering overall data‑center electricity use.
Correct answer is: Upgrading to high‑efficiency power supplies and servers
Q.38 Which of the following is NOT a typical characteristic of a high‑efficiency motor?
Low slip
High power factor
Thick copper windings
Large iron losses
Explanation - High‑efficiency motors are designed to minimize iron (core) losses, not increase them.
Correct answer is: Large iron losses
Q.39 In building energy modeling, the term "U‑value" refers to:
Thermal transmittance, indicating how well a component conducts heat
Electrical resistance of a conductor
Wind speed around the building
Solar irradiance on the roof
Explanation - Lower U‑values represent better insulation performance.
Correct answer is: Thermal transmittance, indicating how well a component conducts heat
Q.40 Which strategy can be used to reduce the peak demand of an industrial plant without changing production output?
Increasing the number of shifts
Implementing load shifting using on‑site energy storage
Reducing the size of machines
Lowering the quality of products
Explanation - Storing energy during low‑demand periods and releasing it during peaks smooths the demand profile.
Correct answer is: Implementing load shifting using on‑site energy storage
Q.41 What does the acronym "LEED" stand for in the context of building sustainability?
Low‑Emission Energy Design
Leadership in Energy and Environmental Design
Local Energy Efficiency Directive
Lightweight Eco‑friendly Engineering Development
Explanation - LEED is a widely recognized green building certification program.
Correct answer is: Leadership in Energy and Environmental Design
Q.42 Which of the following is a disadvantage of using incandescent bulbs compared to LEDs?
Higher luminous efficacy
Longer lifespan
Higher operating temperature and lower energy efficiency
Ability to dim easily
Explanation - Incandescent bulbs convert most input power to heat, making them inefficient.
Correct answer is: Higher operating temperature and lower energy efficiency
Q.43 What is the most effective method to reduce conduction losses in a copper transmission line?
Increasing the cross‑sectional area of the conductor
Decreasing the operating voltage
Using a longer line length
Adding series inductors
Explanation - A larger cross‑section reduces resistance, thereby lowering I²R losses.
Correct answer is: Increasing the cross‑sectional area of the conductor
Q.44 Which of the following is a key advantage of using a digital meter over an analog meter for energy monitoring?
Lower initial cost
Ability to provide real‑time data and remote reading
Higher mechanical durability
No need for calibration
Explanation - Digital meters can communicate usage data instantly, supporting demand‑side management.
Correct answer is: Ability to provide real‑time data and remote reading
Q.45 In an HVAC system, which component recovers heat from exhaust air to pre‑heat incoming fresh air?
Chiller
Heat recovery ventilator (HRV)
Cooling tower
Refrigerant compressor
Explanation - HRVs transfer heat between outgoing and incoming airstreams, improving overall efficiency.
Correct answer is: Heat recovery ventilator (HRV)
Q.46 Which factor most directly influences the efficiency of a photovoltaic (PV) module?
Thickness of the glass cover
Temperature of the cells
Color of the frame
Length of the mounting brackets
Explanation - Higher cell temperatures reduce the voltage output, decreasing overall conversion efficiency.
Correct answer is: Temperature of the cells
Q.47 What is the primary purpose of installing a “set‑back” schedule on a programmable thermostat in winter?
To increase indoor temperature at night
To lower the temperature when occupants are asleep or away, reducing heating energy use
To keep the heating system running continuously
To synchronize with the electric utility's billing cycle
Explanation - Set‑back reduces unnecessary heating, saving energy while maintaining comfort when needed.
Correct answer is: To lower the temperature when occupants are asleep or away, reducing heating energy use
Q.48 Which of the following best describes "load factor"?
Ratio of peak demand to average demand over a period
Ratio of average demand to peak demand over a period
Difference between real and reactive power
Total energy consumption divided by time
Explanation - A higher load factor indicates more consistent usage and better utilization of installed capacity.
Correct answer is: Ratio of average demand to peak demand over a period
Q.49 Which renewable energy technology uses a working fluid that undergoes a phase change to store thermal energy?
Wind turbine
Concentrated solar power (CSP) with molten salt
Photovoltaic panel
Hydroelectric dam
Explanation - Molten salt stores heat captured from sunlight, allowing electricity generation after sunset.
Correct answer is: Concentrated solar power (CSP) with molten salt
Q.50 Which method can be employed to reduce friction losses in a fluid‑transport system for cooling towers?
Increasing pipe length
Using smoother pipe interiors and larger diameters
Adding more bends and elbows
Reducing flow rate to zero
Explanation - Smooth, larger‑diameter pipes lower friction factor, reducing pump energy consumption.
Correct answer is: Using smoother pipe interiors and larger diameters
Q.51 What is the main advantage of using a multi‑level inverter in solar PV systems?
Higher harmonic distortion
Reduced voltage stress on components and higher efficiency
Increased need for cooling fans
Lower conversion efficiency
Explanation - Multi‑level inverters produce output voltages with lower total harmonic distortion and improved efficiency.
Correct answer is: Reduced voltage stress on components and higher efficiency
Q.52 Which building envelope improvement reduces heat loss during winter the most?
Installing reflective exterior paint
Adding exterior continuous insulation
Increasing window size
Using single‑pane glass
Explanation - Continuous insulation reduces thermal bridging, which is a major source of heat loss.
Correct answer is: Adding exterior continuous insulation
Q.53 In the context of energy management, what does the term "baseline" refer to?
The maximum possible energy consumption
The measured energy use prior to implementing conservation measures
The amount of renewable energy generated
The total cost of electricity bills
Explanation - A baseline provides a reference to assess the impact of energy‑saving actions.
Correct answer is: The measured energy use prior to implementing conservation measures
Q.54 Which of the following devices can reduce harmonic distortion caused by non‑linear loads?
Surge protector
Passive harmonic filter
Circuit breaker
Thermostat
Explanation - Passive filters are tuned to absorb specific harmonic frequencies, improving power quality.
Correct answer is: Passive harmonic filter
Q.55 What is the primary function of a "chiller" in a large commercial building?
Generate electricity
Provide cooling by removing heat from water circulated through the HVAC system
Increase indoor humidity
Store solar energy
Explanation - Chillers absorb heat from the building’s water loop and reject it to the outside, delivering chilled water for air‑conditioning.
Correct answer is: Provide cooling by removing heat from water circulated through the HVAC system
Q.56 Which of the following best describes the term "energy intensity"?
Energy consumption per unit area of a building
Total energy generated in a year
Voltage level of the power supply
Number of occupants in a building
Explanation - Energy intensity is often expressed as kWh/m²‑year and is used to compare efficiency of buildings.
Correct answer is: Energy consumption per unit area of a building
Q.57 What is the main reason that DC distribution can be more efficient than AC for data‑center power delivery?
DC requires larger conductors
DC eliminates the need for multiple AC‑DC conversions
DC cannot be used with renewable sources
DC has higher line losses
Explanation - Data‑centers often use DC loads (servers, LEDs), so a DC bus reduces conversion steps and associated losses.
Correct answer is: DC eliminates the need for multiple AC‑DC conversions
Q.58 Which of the following is an example of a behavioral energy‑saving measure?
Installing LED lighting
Using a building automation system
Turning off equipment when not in use
Upgrading to high‑efficiency motors
Explanation - Behavioral measures involve changes in user habits to reduce unnecessary energy consumption.
Correct answer is: Turning off equipment when not in use
Q.59 In a solar PV system, what does the term "derating factor" account for?
Losses due to temperature, wiring, and inverter efficiency
Increase in solar irradiance
Improvement in module efficiency over time
Height of the solar array
Explanation - Derating reduces the name‑plate capacity to realistic expected output.
Correct answer is: Losses due to temperature, wiring, and inverter efficiency
Q.60 Which method is most suitable for reducing the standby power consumption of a large office building’s IT equipment?
Installing motion sensors on lighting
Using power‑managed servers and enabling sleep modes
Increasing the HVAC set‑point
Painting walls with reflective paint
Explanation - Power‑managed IT hardware can automatically enter low‑power states when idle, cutting standby draw.
Correct answer is: Using power‑managed servers and enabling sleep modes
Q.61 What is the main purpose of a "thermal storage tank" in a district heating system?
To store excess electricity
To store hot water or steam for use during peak heating demand
To increase the pressure of the network
To filter impurities from the water
Explanation - Thermal storage decouples heat generation from consumption, improving system efficiency.
Correct answer is: To store hot water or steam for use during peak heating demand
Q.62 Which of the following lighting control strategies provides the greatest energy savings in an office with variable occupancy?
Fixed‑time switching
Daylight harvesting combined with occupancy sensors
Manual switch control by occupants
Always‑on lighting
Explanation - Combining daylight sensors with occupancy detection adjusts lighting levels dynamically, maximizing savings.
Correct answer is: Daylight harvesting combined with occupancy sensors
Q.63 In electrical distribution, what does the term "short‑circuit current" refer to?
The current flowing during normal operation
The maximum current that can flow when a fault occurs
The current used by lighting fixtures
The current measured by a digital multimeter
Explanation - Short‑circuit current is the high current resulting from a low‑impedance fault, dictating protective device ratings.
Correct answer is: The maximum current that can flow when a fault occurs
Q.64 Which of the following is an advantage of using a "tri‑level inverter" for renewable energy integration?
Higher voltage stress on semiconductor devices
Reduced total harmonic distortion and better efficiency
Increased size and weight
Higher cost of cooling
Explanation - Tri‑level inverters produce multiple voltage steps, lowering harmonic content and improving conversion efficiency.
Correct answer is: Reduced total harmonic distortion and better efficiency
Q.65 What is the primary function of a "static VAR compensator" (SVC) in a power system?
To store kinetic energy
To provide fast reactive power support and improve voltage stability
To convert AC to DC power
To increase line resistance
Explanation - SVCs inject or absorb reactive power quickly, helping maintain voltage levels under varying loads.
Correct answer is: To provide fast reactive power support and improve voltage stability
Q.66 Which of the following actions directly reduces the "energy use intensity" (EUI) of a commercial building?
Increasing the number of occupants
Installing a larger HVAC system
Improving the building envelope and upgrading equipment
Adding more lighting fixtures
Explanation - Better insulation, efficient HVAC, and lighting lower total energy per floor area, reducing EUI.
Correct answer is: Improving the building envelope and upgrading equipment
Q.67 Which renewable energy source typically has the highest capacity factor among wind, solar PV, and hydroelectric?
Wind
Solar PV
Hydroelectric
All have similar capacity factors
Explanation - Hydroelectric plants can run continuously and have capacity factors often above 50%, higher than typical wind or solar.
Correct answer is: Hydroelectric
Q.68 What is the most effective way to reduce transmission line losses caused by the "skin effect" at high frequencies?
Using solid copper conductors
Increasing the line length
Using conductors with larger cross‑section and stranded construction
Operating at lower voltages
Explanation - Stranded conductors increase surface area, mitigating skin effect and reducing AC resistance.
Correct answer is: Using conductors with larger cross‑section and stranded construction
Q.69 Which of the following building codes primarily addresses energy conservation in new constructions?
International Building Code (IBC)
International Energy Conservation Code (IECC)
National Fire Protection Association (NFPA) 70
American Society of Heating, Refrigerating and Air‑Conditioning Engineers (ASHRAE) 90.1
Explanation - IECC sets minimum energy efficiency requirements for new and renovated buildings.
Correct answer is: International Energy Conservation Code (IECC)
Q.70 Which of the following devices can be used to limit the maximum power draw of a large motor during start‑up?
Soft starter
Transformer
Capacitor bank
Circuit breaker
Explanation - Soft starters gradually ramp up voltage, reducing inrush current and mechanical stress.
Correct answer is: Soft starter
Q.71 In an energy audit, the "payback period" refers to:
The time it takes for an energy‑saving measure to pay for itself through cost savings
The duration of the audit process
The period over which energy prices are fixed
The lifespan of the equipment
Explanation - Payback period is a key metric for assessing the economic viability of conservation projects.
Correct answer is: The time it takes for an energy‑saving measure to pay for itself through cost savings
Q.72 Which technology enables the conversion of waste heat from industrial processes into electricity?
Thermoelectric generators (TEGs)
Solar PV panels
Wind turbines
Hydraulic turbines
Explanation - TEGs exploit the Seebeck effect to convert temperature differences directly into electric voltage.
Correct answer is: Thermoelectric generators (TEGs)
Q.73 What is the main benefit of using a "dual‑fuel" boiler in an industrial plant?
Higher emissions
Ability to switch between fuels (e.g., natural gas and oil) to optimize cost and availability
Increased maintenance requirements
Reduced efficiency
Explanation - Dual‑fuel capability provides flexibility and can improve overall energy economics.
Correct answer is: Ability to switch between fuels (e.g., natural gas and oil) to optimize cost and availability
Q.74 Which of the following is a key factor in selecting an appropriate size for an on‑site battery storage system?
Peak demand of the facility
Color of the battery casings
Number of windows in the building
Height of the building
Explanation - Battery capacity must be sized to meet the intended peak‑shaving or backup requirements.
Correct answer is: Peak demand of the facility
Q.75 What does the term "rebound effect" describe in energy efficiency initiatives?
Increased overall energy use because of lower operating costs after efficiency improvements
Reduced electricity tariffs
Higher emissions from renewable sources
Improved building comfort
Explanation - When efficiency reduces cost, users may increase consumption, offsetting some savings.
Correct answer is: Increased overall energy use because of lower operating costs after efficiency improvements
Q.76 Which type of insulation is most suitable for high‑temperature industrial piping?
Fiberglass blanket
Mineral wool
Calcium silicate
Cellulose
Explanation - Calcium silicate insulation can withstand temperatures up to 1150 °C, making it ideal for hot pipes.
Correct answer is: Calcium silicate
Q.77 In a smart home, which device can automatically adjust blinds based on solar irradiance to reduce cooling load?
Smart thermostat
Motorized blind controller with light sensor
Smart plug
Voice assistant
Explanation - Such controllers close blinds when sunlight intensity is high, lowering solar heat gain.
Correct answer is: Motorized blind controller with light sensor
Q.78 Which of the following is NOT a typical benefit of implementing a demand response (DR) program?
Reduced peak load on the grid
Lower electricity prices for participants
Increased renewable energy penetration
Higher emissions from fossil plants
Explanation - DR programs aim to reduce emissions by lowering peak demand and enabling cleaner generation.
Correct answer is: Higher emissions from fossil plants
Q.79 Which of the following methods can be used to improve the efficiency of a centrifugal pump in a water distribution system?
Operating the pump far from its Best Efficiency Point (BEP)
Installing a variable speed drive to match flow demand
Increasing the pipe diameter unnecessarily
Reducing the suction head
Explanation - VSDs allow the pump to operate near its BEP across a range of flow rates, saving energy.
Correct answer is: Installing a variable speed drive to match flow demand
Q.80 What is the main purpose of a "heat sink" in power electronics?
To store electrical energy
To dissipate waste heat and maintain component temperatures within safe limits
To increase voltage
To generate power
Explanation - Heat sinks increase surface area, allowing convection and radiation to remove heat from devices.
Correct answer is: To dissipate waste heat and maintain component temperatures within safe limits
Q.81 Which of the following strategies helps reduce energy consumption of a residential refrigerator?
Setting the thermostat to a colder temperature than needed
Keeping the door open frequently
Ensuring proper door seals and maintaining a temperature of 3‑5 °C
Placing the refrigerator near a heat source
Explanation - Good seals prevent cold air loss; optimal temperature avoids unnecessary compressor run‑time.
Correct answer is: Ensuring proper door seals and maintaining a temperature of 3‑5 °C
Q.82 Which of the following best describes "cogeneration"?
Generating electricity only from renewable sources
Simultaneous production of electricity and useful heat from the same energy source
Separate generation of electricity and heat at different sites
Storing electricity in batteries
Explanation - Cogeneration (CHP) utilizes waste heat from electricity generation, improving overall fuel efficiency.
Correct answer is: Simultaneous production of electricity and useful heat from the same energy source
Q.83 What is the typical range of the coefficient of performance (COP) for modern residential air‑source heat pumps?
0.5‑0.9
1.0‑1.5
2.5‑4.0
5.0‑6.5
Explanation - COP values between 2.5 and 4 indicate that the heat pump delivers 2.5‑4 times more heat energy than the electrical energy it consumes.
Correct answer is: 2.5‑4.0
Q.84 Which of the following lighting technologies typically has the longest lifespan?
Incandescent bulbs
Fluorescent tubes
LED lamps
Halogen lamps
Explanation - LEDs can operate for 25,000–50,000 hours, far exceeding other common lighting technologies.
Correct answer is: LED lamps
Q.85 In an energy‑efficient building, which zone is most critical to insulate to reduce heating loads?
Attic/roof
Basement
Interior walls
Ceiling of the living room
Explanation - Heat rises; a poorly insulated roof leads to significant heat loss in winter.
Correct answer is: Attic/roof
Q.86 What is the primary advantage of using a "triac" in lighting dimmer circuits?
It can handle high voltages without heat
It provides smooth phase‑control dimming with low component count
It increases the light output
It converts AC to DC
Explanation - Triacs allow rapid switching of AC phases, enabling efficient dimming of incandescent and some LED loads.
Correct answer is: It provides smooth phase‑control dimming with low component count
Q.87 Which of the following measures can reduce the "heat island" effect in urban areas?
Increasing asphalt pavement
Planting trees and using reflective roofing materials
Building taller structures
Installing more street lights
Explanation - Vegetation and high‑albedo surfaces lower surface temperatures, mitigating heat islands.
Correct answer is: Planting trees and using reflective roofing materials
Q.88 In a power factor correction capacitor bank, what is the typical unit of capacitance used?
Ohms (Ω)
Henries (H)
Farads (F)
Watts (W)
Explanation - Capacitance is measured in farads, and capacitor banks are sized in kVAR using this unit.
Correct answer is: Farads (F)
Q.89 Which of the following statements about "energy harvesting" is correct?
It stores large amounts of energy for grid use
It captures small amounts of ambient energy (e.g., vibration, light) to power low‑power devices
It is only applicable to large power plants
It always requires batteries
Explanation - Energy harvesting techniques scavenge energy from the environment for sensors, wearables, etc.
Correct answer is: It captures small amounts of ambient energy (e.g., vibration, light) to power low‑power devices
Q.90 What is the most common cause of "voltage sag" in industrial power systems?
Excessive solar generation
Sudden large motor starting or short‑circuit faults
High ambient temperature
Long transmission lines
Explanation - High inrush currents cause temporary drops in voltage, known as sags.
Correct answer is: Sudden large motor starting or short‑circuit faults
Q.91 Which of the following is a typical characteristic of a "grid‑tied" solar inverter?
It can operate independently of the utility grid
It synchronizes its output frequency and voltage with the utility grid
It stores excess energy in batteries
It reduces the voltage of the grid
Explanation - Grid‑tied inverters match the grid’s phase, frequency, and voltage to feed power safely.
Correct answer is: It synchronizes its output frequency and voltage with the utility grid
Q.92 Which of the following is the most efficient way to reduce the cooling load of a data center?
Increasing the set‑point temperature of the CRAC units
Using hot‑aisle/cold‑aisle containment and free‑cooling techniques
Installing more high‑speed fans
Running servers at maximum capacity continuously
Explanation - Containment prevents mixing of hot and cold air, and free‑cooling uses outside air when conditions allow, drastically cutting chiller energy use.
Correct answer is: Using hot‑aisle/cold‑aisle containment and free‑cooling techniques
Q.93 What does the term "load shedding" refer to in electricity management?
Increasing generation capacity
Intentionally disconnecting part of the load to maintain system stability
Installing larger transformers
Reducing transmission line length
Explanation - Load shedding is a controlled measure to prevent system collapse during peak demand or emergencies.
Correct answer is: Intentionally disconnecting part of the load to maintain system stability
Q.94 Which of the following technologies can convert waste heat from industrial processes directly into electricity with no moving parts?
Thermoelectric generators (TEG)
Steam turbine
Wind turbine
Hydroelectric turbine
Explanation - TEGs use the Seebeck effect to generate electricity from temperature differences without mechanical components.
Correct answer is: Thermoelectric generators (TEG)
Q.95 In building energy management, what does the term "setpoint" refer to?
The maximum power rating of a transformer
The desired temperature, humidity, or lighting level that a control system strives to maintain
The length of a conduit
The color of a building’s exterior paint
Explanation - Setpoints are target values used by controllers to achieve energy‑efficient operation.
Correct answer is: The desired temperature, humidity, or lighting level that a control system strives to maintain
Q.96 Which of the following is a major source of energy loss in a motor‑driven pump system?
Hydraulic losses in the piping
Magnetic hysteresis in the motor core
Friction losses in the motor bearings
All of the above
Explanation - Motor‑driven pump systems suffer from hydraulic, magnetic, and mechanical losses, all contributing to overall inefficiency.
Correct answer is: All of the above
Q.97 Which of the following building design elements can significantly reduce cooling loads in hot climates?
Large glass facades with no shading
Light‑colored reflective roofing and exterior shading devices
Dark interior paint
High indoor humidity levels
Explanation - Reflective roofs and shading reduce solar heat gain, lowering the need for mechanical cooling.
Correct answer is: Light‑colored reflective roofing and exterior shading devices
Q.98 What is the main purpose of a "power factor correction" capacitor bank in an industrial facility?
To increase the real power consumption
To supply reactive power and reduce the facility's apparent power demand
To store energy for later use
To convert AC to DC
Explanation - Capacitor banks provide leading reactive power, improving the power factor and reducing current draw.
Correct answer is: To supply reactive power and reduce the facility's apparent power demand
Q.99 Which of the following actions is considered a passive energy‑conservation measure?
Installing a programmable thermostat
Adding insulation to walls and roofs
Replacing motors with VFDs
Implementing demand‑response contracts
Explanation - Passive measures improve the building envelope without active control systems.
Correct answer is: Adding insulation to walls and roofs
Q.100 Which of the following best explains why a high‑efficiency motor typically has a lower "no‑load" loss than a standard motor?
It uses a larger rotor
It incorporates improved core materials and reduced copper losses
It operates at a higher voltage
It has a thicker shaft
Explanation - High‑efficiency designs minimize core (iron) and copper losses, especially noticeable at no‑load.
Correct answer is: It incorporates improved core materials and reduced copper losses
Q.101 What is the primary benefit of using daylight‑responsive lighting controls in office spaces?
Increasing the number of light fixtures required
Reducing electric lighting consumption by adjusting artificial light based on natural daylight levels
Eliminating the need for emergency lighting
Increasing the building’s heat loss
Explanation - Daylight sensors dim or switch off lights when sufficient natural light is present, saving energy.
Correct answer is: Reducing electric lighting consumption by adjusting artificial light based on natural daylight levels
Q.102 Which of the following renewable energy sources typically requires the least land area per megawatt of installed capacity?
On‑shore wind
Solar PV
Hydroelectric (large dam)
Geothermal
Explanation - Geothermal plants have a small surface footprint compared to wind farms and solar farms.
Correct answer is: Geothermal
Q.103 Which of the following is a common method for reducing "thermal bridging" in building construction?
Using continuous insulation and thermal breaks at structural elements
Increasing the number of windows
Applying glossy paint on interior walls
Installing larger HVAC ducts
Explanation - Thermal breaks interrupt heat flow through conductive elements, reducing overall heat loss.
Correct answer is: Using continuous insulation and thermal breaks at structural elements
Q.104 What does the abbreviation "BEMS" stand for in the context of energy management?
Building Energy Management System
Battery Energy Monitoring Service
Binary Energy Modulation Scheme
Basic Electrical Maintenance Standard
Explanation - BEMS refers to an integrated platform that monitors and controls building energy‑using equipment.
Correct answer is: Building Energy Management System
Q.105 Which of the following factors most directly influences the seasonal efficiency of an air‑conditioner?
Seasonal Energy Efficiency Ratio (SEER)
Color of the unit’s casing
Length of the power cord
Number of fan blades
Explanation - SEER quantifies the cooling output per unit of electrical input over a typical cooling season.
Correct answer is: Seasonal Energy Efficiency Ratio (SEER)
Q.106 Which type of motor typically offers the highest efficiency for variable‑speed applications?
Squirrel‑cage induction motor with VFD
Permanent magnet synchronous motor (PMSM) with inverter drive
Universal motor
Single‑phase shaded‑pole motor
Explanation - PMSMs have high efficiency across a wide speed range, especially when paired with inverter drives.
Correct answer is: Permanent magnet synchronous motor (PMSM) with inverter drive
Q.107 What is the most common reason for installing a "thermal storage tank" in a solar water‑heating system?
To increase the temperature of the solar collectors
To store excess heat for use during periods without sunlight
To convert solar heat directly into electricity
To reduce the size of the solar panels
Explanation - Thermal storage buffers the intermittent nature of solar heat, providing hot water on demand.
Correct answer is: To store excess heat for use during periods without sunlight
Q.108 Which of the following devices is most suitable for reducing harmonic currents caused by a large number of computer power supplies?
Passive low‑pass filter
Active harmonic filter
Surge protector
Circuit breaker
Explanation - Active filters dynamically inject opposite‑phase currents to cancel harmonics, suitable for complex loads.
Correct answer is: Active harmonic filter
Q.109 Which of the following is a typical advantage of using a "ground‑source heat pump" (GSHP) over an air‑source heat pump?
Higher efficiency due to relatively constant ground temperature
Requires no drilling or excavation
Operates only during summer
Higher noise levels
Explanation - GSHPs exploit the stable temperature of the earth, delivering higher COPs year‑round.
Correct answer is: Higher efficiency due to relatively constant ground temperature
Q.110 In the context of energy conservation, what does the term "retro‑commissioning" refer to?
Designing a new building from scratch
Testing and adjusting existing building systems to improve performance after construction
Adding more lighting fixtures
Installing a new roof
Explanation - Retro‑commissioning optimizes the operation of existing equipment to recover lost efficiency.
Correct answer is: Testing and adjusting existing building systems to improve performance after construction
Q.111 Which of the following measures can reduce the "parasitic" losses in a transformer?
Increasing the core size without changing material
Using amorphous steel cores and high‑quality winding techniques
Operating at a lower voltage
Adding more tap changers
Explanation - Amorphous steel has lower hysteresis loss, and precise winding reduces copper loss, both lowering parasitic losses.
Correct answer is: Using amorphous steel cores and high‑quality winding techniques
Q.112 What is the main purpose of a "variable air volume" (VAV) system in commercial HVAC?
To maintain constant airflow regardless of load
To modulate airflow based on zone temperature demand, saving energy
To increase the temperature of supply air
To provide ventilation only at night
Explanation - VAV boxes adjust fan speed and damper position to meet the exact heating/cooling demand of each zone.
Correct answer is: To modulate airflow based on zone temperature demand, saving energy
Q.113 Which of the following is the most effective method for reducing the "heat loss" through a building’s windows?
Installing double or triple glazing with low‑E coating
Using larger single‑pane windows
Painting the glass black
Removing curtains
Explanation - Multiple panes with low‑E coatings greatly reduce conductive and radiative heat transfer.
Correct answer is: Installing double or triple glazing with low‑E coating
Q.114 Which of the following is a primary environmental benefit of increasing building energy efficiency?
Higher CO₂ emissions
Reduced demand for fossil fuel generation and lower greenhouse‑gas emissions
Increased water consumption
More frequent equipment failures
Explanation - Energy‑efficient buildings consume less power, decreasing the need for carbon‑intensive generation.
Correct answer is: Reduced demand for fossil fuel generation and lower greenhouse‑gas emissions
Q.115 What does the term "net zero energy building" (NZEB) mean?
A building that produces exactly as much energy as it consumes over a year, typically using on‑site renewables
A building with no electricity connections
A building that uses only fossil fuels
A building with zero lighting
Explanation - NZEBs balance annual energy use with on‑site generation, achieving net zero energy consumption.
Correct answer is: A building that produces exactly as much energy as it consumes over a year, typically using on‑site renewables
Q.116 Which of the following control strategies can be used to minimize energy use of a commercial chiller plant during off‑peak hours?
Running the chiller at full capacity 24/7
Implementing thermal storage to shift cooling load to off‑peak periods
Increasing the set‑point temperature during peak hours
Reducing water flow through the cooling towers
Explanation - Thermal storage (e.g., chilled water tanks) allows chillers to run when electricity is cheaper, reducing peak demand.
Correct answer is: Implementing thermal storage to shift cooling load to off‑peak periods
Q.117 Which of the following is a typical characteristic of a high‑efficiency LED driver?
Low power factor
High total harmonic distortion (THD)
Constant current output with high efficiency and low THD
Requires a separate cooling system
Explanation - LED drivers are designed to deliver stable current, maintain high efficiency, and minimize harmonic distortion.
Correct answer is: Constant current output with high efficiency and low THD
Q.118 Which of the following best describes the purpose of a "thermal imaging camera" in an energy audit?
Measuring voltage levels
Detecting temperature differences to locate insulation defects and heat leaks
Recording audio noise levels
Measuring humidity
Explanation - Thermal cameras visualize heat flow, helping auditors identify areas of energy loss.
Correct answer is: Detecting temperature differences to locate insulation defects and heat leaks