Category: Renewable Energy Objective Questions

Solar Energy Multiple Choice Questions on “Solar Water Heater”.

1. What is solar water heater?
a) Use solar energy to heat water
b) Use solar energy to generate current which is then used to heat water
c) Use water to generate heat
d) Use solar energy to generate steam
Answer: a
Clarification: Solar water heater is a system that converts sunlight into heat. This heat is then used to heat water. As the water gets heated, steam may be produced but the purpose of solar water is to heat water and not produce steam. It does not generate current.

2. Which of the following determines complexity and size of solar water heating system?
a) Food
b) Changes in ambient temperature
c) Chemicals
d) Solar radiation constant
Answer: b
Clarification: Changes in ambient temperature during day-night cycle is one of the factors that determines the complexity and size of solar water heating system. Food, chemicals and solar radiation constant does not influence the complexity and size of the system.

3. What is freeze protection in a solar water heating system?
a) Ensures that the system is frozen
b) Prevents the operation of drainback system
c) Prevents damage to system due to freezing of transfer fluid
d) Ensures that the transfer fluid is frozen
Answer: c
Clarification: Freeze protection in a solar water system prevents the system being damaged due to freezing of transfer fluid. It does not prevent the operation of drainback system.

4. What are drainback systems in solar water heating system?
a) The system that reverses the direction of flow of transfer fluid
b) The system that tracks the sun
c) The system that pumps excess transfer fluid
d) The system that drains the transfer fluid
Answer: d
Clarification: Drainback systems are systems that drain the transfer fluid particularly to ensure freeze protection. This prevents the freezing of transfer fluid and any unwanted damage to the system.

5. How does freeze-tolerance work?
a) By expansion of pipes carrying transfer fluid
b) By compression of pipes carrying transfer fluid
c) By increasing the temperature of pipes carrying transfer fluid
d) By increasing the pressure inside pipes carrying transfer fluid
Answer: a
Clarification: Freeze-tolerance works by expansion of pipes carrying the transfer fluid. The low pressure pipes are made of silicone rubber that expands on freezing.

6. Which of the following metals are used to make pipes of low cost solar water heating system?
a) Gold
b) Copper
c) Polymer
d) Silver
Answer: b
Clarification: Copper is used to make pipes of low cost solar water heating systems. Though silver and gold are good thermal conductors they are expensive. Polymer is not a metal.

7. Direct solar water heating systems ______
a) offer great overheating protection
b) are called pumped systems
c) offer no overheating protection
d) offer great freeze protection
Answer: c
Clarification: Direct solar water heating systems are also called compact systems. They offer little or no overheating protection unless they have a heat export pump.

8. How is the heat transferred from transfer fluid to potable water in indirect solar water heating systems?
a) By directly exposing the substance to sunlight
b) By using an electrical heater
c) By circulating potable water through the collector
d) By using heat exchanger
Answer: d
Clarification: An indirect solar water heating system uses a heat exchanger to transfer heat from the transfer fluid to the potable water. It does not expose the transfer fluid directly to the sunlight and does not use an electrical heater.

9. How is water heated in a direct solar water heating system?
a) By circulating potable water through the collector
b) By directly exposing water to sunlight
c) By using convection from a different transfer fluid
d) By using heat exchanger
Answer: a
Clarification: In a direct solar water heating system, the potable water is the transfer fluid. Hence, it is heated by circulating through the collector. Indirect solar water heating systems use a heat exchanger.

10. Passive systems rely on heat-driven convection.
a) False
b) True
Answer: b
Clarification: Passive systems rely on heat-driven convection. If not, they also use heat pipes to circulate the working fluid through the collector and heat it. Hence, they are cheap and are easily maintained.

11. Which of the following is an example of direct solar water heating system?
a) Pressurised antifreeze system
b) Pumped systems to circulate transfer fluid
c) Convection heat storage system
d) Drainback system
Answer: c
Clarification: Convection heat storage system is similar to an integrated collector storage system. Both these systems are examples of direct solar water heating systems.

12. How is the heat transfer fluid (HTF) heated in bubble pump systems?
a) By subjecting the closed HTF circuit to high pressure
b) By subjecting the closed HTF circuit to high pressure and by increasing the volume
c) By subjecting the closed HTF circuit to low pressure and by decreasing the volume
d) By subjecting the closed HTF circuit to low pressure
Answer: d
Clarification: In a bubble pump system, the heat transfer fluid circuit is subjected to a low pressure. This causes the liquid to boil at low temperatures as the sun heats it. The volume is not changed.

13. Batch collectors reduce heat loss by thermally insulating the storage tank.
a) True
b) False
Answer: a
Clarification: Batch collectors reduce heat loss by thermally insulating the storage tank. This is done by covering the tank in a glass-topped box that allows heat from sun to reach the water tank and traps it – greenhouse effect.

14. Overheat protection is done by passing hot water through collector during night.
a) False
b) True
Answer: b
Clarification: Overheat protection is done by passing hot water through collector during night or when there is less sunlight. This is extremely effective in direct or thermal store plumbing and ineffective in evacuated-tube collectors.

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Biomass Energy Multiple Choice Questions on “Biomass Conversion Technologies – 1”.

1. Which of the following technologies are used to convert biomass into useful energy forms?
a) Bio-chemical process
b) Galvanization
c) Doping
d) Photoelectric effect

Answer: a
Clarification: The three main technologies used to convert biomass into useful forms of energy are bio-chemical, thermo-chemical and physio-chemical processes. Galvanization is a process used to prevent corrosion of metals. Doping and photoelectric effect are not related to biomass conversion technologies.

2. What are the four main types of thermo-chemical processes?
a) Galvanization, photovoltaic effect, chemo-mechanical effect, pyrolysis
b) Pyrolysis, gasification, combustion, hydrothermal processing
c) Pyrolysis, gasification, combustion, doping
d) Photovoltaic effect, gasification, combustion, hydrothermal processing

Answer: b
Clarification: The four main types of thermo-chemical processes are pyrolysis, gasification, combustion and hydrothermal processing. Photovoltaic effect, doping, chemo-mechanical effect and galvanization are not related to biomass conversion technologies.

3. What are the two primary processes under bio-chemical conversion?
a) Photosynthesis and respiration
b) Photosynthesis and photovoltaic
c) Anaerobic digestion and fermentation
d) Anaerobic digestion and photosynthesis

Answer: c
Clarification: Anaerobic digestion and fermentation are two primary processes under bio-chemical conversion. Photosynthesis, photovoltaic and respiration are not related to biomass conversion technologies.

4. Which of the following is an example of physio-chemical conversion technique to convert biomass into usable forms of energy?
a) Pyrolysis
b) Gasification
c) Anaerobic Digestion
d) Extraction with esterification

Answer: d
Clarification: Physio-chemical process mainly consists of extraction with esterification. Pyrolysis and gasification are thermo-chemical conversion. Anaerobic digestion is a bio-chemical conversion process.

5. Which of the following is a product of pyrolysis of biomass?
a) Producer gas
b) Steel
c) Agricultural residue
d) Sodium

Answer: a
Clarification: The output is producer gas. Steel and sodium are not the outputs of any pyrolysis process. Agricultural residue is a type of biomass.

6. Pyrolysis occurs in the presence of _______ oxygen.
a) large amounts of
b) absence of
c) extremely large amount of
d) low amounts of

Answer: b
Clarification: In pyrolysis, the biomass is subjected to high temperatures in the absence of oxygen. The output of pyrolysis is producer gas which is a mixture of flammable gases (primarily CO and H2) and non-flammable gases (primarily nitrogen and carbon dioxide).

7. Which of the following best indicates the process of gasification?
a) Biomass → carbon dioxide and water → producer gas and charcoal → carbon monoxide and hydrogen
b) Biomass → carbon monoxide and hydrogen → carbon dioxide and water → producer gas and charcoal
c) Biomass → producer gas and charcoal → carbon dioxide and water → carbon monoxide and hydrogen
d) Producer gas and charcoal → carbon dioxide and water → carbon monoxide and hydrogen → biomass

Answer: c
Clarification: Gasification basically converts all the available biomass to “gas”. In the first stage, the biomass is partially combusted to form producer gas and charcoal which is then sent to the second stage. In the second stage, the carbon dioxide and water produced in the first stage is chemically reduced by charcoal to form carbon monoxide and hydrogen.

8. Which of the following is best suited for hydrothermal processing?
a) Forestry byproducts
b) Wheat
c) Corn
d) Sewage sludge

Answer: d
Clarification: Feedstocks with high moisture content like sewage sludge are suitable for hydrothermal processing. Agricultural residue like wheat and corn and forestry byproducts are not best suited for hydrothermal processing.

9. What is hydrothermal processing?
a) Heating aqueous slurries of biomass at high pressures to produce products of greater energy density
b) Heating aqueous slurries of biomass at high temperatures to produce products of lower energy density
c) Heating aqueous slurries of biomass at low pressures to produce products of greater energy density
d) Heating aqueous slurries of biomass at low temperatures to produce products of lower energy density

Answer: a
Clarification: Hydrothermal processing is a biomass conversion technique that involves heating of aqueous slurries of biomass at high pressures to produce products of greater energy density. Feedstocks with high moisture content like manures are best suited for this process.

10. What is anaerobic digestion?
a) Produces biogas by heating the biomass
b) Produces biogas using micro-organisms operating in anaerobic conditions
c) Produces biogas by subjecting the biomass to high pressures
d) Produces biogas using micro-organisms operating in aerobic conditions

Answer: b
Clarification: Anaerobic digestion is a biological process of breaking down the biomass to produce products with high energy density – biogas. It occurs in anaerobic conditions. Waste water treatment plants commonly use anaerobic conditions to treat the influent.

11. Catalytic liquefaction occurs at _________
a) low temperature, low pressure
b) high temperature, high pressure
c) low temperature, high pressure
d) high temperature, low pressure

Answer: c
Clarification: Catalytic liquefaction is a thermo-chemical biomass conversion process. It requires low temperature and high pressure and the process is carried out in liquid phase under the presence of a catalyst.

12. Sugarcane is used to produce ethanol.
a) True
b) False

Answer: a
Clarification: One of the most commonly used feedstocks to produce ethanol is sugarcane. This is very popular in developing due to the high productivity of sugarcane when supplied with sufficient water.

13. Which of the following are used to produce ethanol when water is not available in plenty?
a) Sugarcane
b) Wheat
c) Corn
d) Sorghum

Answer: d
Clarification: Cassava or sorghum is commonly used to produce ethanol when water is not available in plenty. Sugarcane is used when there is no limitation on water content. Wheat and corn do not produce ethanol.

14. Which of the following are commonly used in fermentation process?
a) Yeast
b) Bacteria
c) Mushrooms
d) Virus

Answer: a
Clarification: Yeast is commonly used in fermentation process. Fermentation is the process converting biomass to alcohol and carbon dioxide.

15. Fermentation is aerobic process.
a) True
b) False

Answer: b
Clarification: Fermentation is an anaerobic process. It is another commonly used bio-chemical process of converting feedstock (biomass) to energy in the presence of micro-organisms.

Renewable Energy Questions on “Hydrogen Energy – 2”.

1. By what means can hydrogen be stored?
a) Physically and chemically
b) As atoms
c) As ions
d) As fuel cells
Answer: a
Clarification: Hydrogen can be stored either by physical or chemical means. Hydrogen atoms cannot be stored. Ions are intermediate species and exist only in reactions. Fuel cells are not used to store hydrogen.

2. How is hydrogen stored physically?
a) As atoms
b) By compressing hydrogen gas
c) In the form of hydrides
d) In the form of water
Answer: b
Clarification: For physical storage, the convention is to compress hydrogen gas and store it. Hydrogen atoms cannot be stored. Hydrogen is not stored as water. Besides, hydrides and water are not physical means of storing hydrogen.

3. How is hydrogen stored chemically?
a) As ions
b) By compressing hydrogen gas
c) In the form of hydrides
d) In the form of ice
Answer: c
Clarification: Conventionally, hydrogen molecules are converted to hydrides and stored. Ions are intermediate species and cannot be stored. Compression of hydrogen gas is a physical means of storage.

4. Hydrogen molecules are dissociated either _________ or _________ to form hydrides.
a) under sunlight or cold temperatures
b) by substitution or electrolysis
c) by electrolysis or heterolytically
d) homolytically or heterolytically
Answer: d
Clarification: Hydrogen molecules are dissociated either homolytically or heterolytically to form hydrides. This technique is a chemical means to store hydrogen. Electrolysis generates hydrogen. Substitution is a type of organic reaction.

5. Cryogenic adsorption is a physical means to store hydrogen.
a) True
b) False
Answer: a
Clarification: Cryogenic adsorption is a physical means to store hydrogen. After adsorbing hydrogen at low temperatures, it is stored as liquid hydrogen.

6. What are the main components of a fuel cell?
a) Anode, cathode, electrolyte
b) Anode, cathode, membrane and electrolyte (including fuel)
c) Anode, cathode
d) Anode, cathode, electrolyte and connecting wires
Answer: b
Clarification: Fuel cell is a device that converts chemical energy to electrical energy. It consists of the two electrodes namely, anode and cathode, a proton exchange membrane through with protons flow and the electrolyte in each chamber.

7. What is hydrogen compressor do to hydrogen?
a) Increases both pressure and volume
b) Decreases both pressure and volume
c) Increases pressure and decreases volume
d) Decreases pressure and increases volume
Answer: c
Clarification: Hydrogen compressor is a device that increases the pressure of hydrogen by reducing its volume. This results in the formation of compressed hydrogen or liquid hydrogen.

8. What is photocatalytic water splitting?
a) Splitting of water using catalyst and electricity
b) Splitting of water using electricity
c) Combining hydrogen and oxygen to form water
d) Splitting of water using light as catalyst
Answer: d
Clarification: Photocatalytic water splitting is an artificial photosynthesis process that is used to dissociate water into its constituents under the presence of natural or artificial light. It does not use chemical catalyst or electricity.

9. Which of the following uses hydrogen as fuel?
a) Vehicles
b) AA battery
c) AAA battery
d) Power plants
Answer: a
Clarification: Among the given options, vehicles use hydrogen as fuel. They are generally called hydrogen vehicles or hydrogen powered vehicles. These vehicles are powered using fuel cells.

10. Efficiency of water electrolysis is greater than the efficiency of steam reforming.
a) True
b) False
Answer: a
Clarification: Efficiency of water electrolysis is greater than the efficiency of steam reforming. However, electrolysis is not preferred because it is expensive.

Renewable Energy Multiple Choice Questions on “Energy Scenario in India – 2”.

1. How is India’s oil consumption met?
a) Through imports
b) Through exports
c) Through chemical industries
d) Through distillation
Answer: a
Clarification: 79% of India’s oil consumption is met through imports. Chemical industries only help if crude oil is available. Distillation is the process of separating out contaminants from a liquid.

2. What is the biggest nuclear power plant in India?
a) Vindhyachalul
b) Kudankulam
c) Mundra
d) Muppandal
Answer: b
Clarification: Kundankulam Nuclear Power Plant is the largest nuclear power plant in India. Vindhyachal and Mundra are thermal power stations. Muppandal windfarm is the largest wind power plant in India.

3. Where Kundakulam Nuclear Power Plant located in India?
a) Andhra Pradesh
b) Telangana
c) Tamil Nadu
d) Gujarat
Answer: c
Clarification: Kundakulam Nuclear Power Plant is located in Kundakulam in Tirunelveli district of Tamil Nadu. It is the largest nuclear power plant in India with a capacity of 2000 MW.

4. Which sector dominates hydroelectric power production in India?
a) Private
b) NGOs
c) Food industry
d) Public sector
Answer: d
Clarification: Public sector dominates hydroelectric power production in India. It accounts for about 92.5% percent of India’s hydroelectric power. Private sector, food industry and NGOs do not dominate hydroelectric power production in India.

5. Why can’t the government exploit the hydroelectric potential of Godavari, Narmada and other rivers flowing through central India?
a) Because of opposition from tribal population
b) Because of finances
c) Because disputes between central and respective state governments
d) Because of poor land quality
Answer: a
Clarification: Government is unable to exploit the hydroelectric potential of Godavari, Narmada and other rivers flowing through central India. This is because of opposition from tribal population. They are worried that construction of dams might damage their habitat.

6. Which of the following is an example of public sector hydroelectric companies?
a) Hindustan Petroleum
b) NHPC
c) BHEL
d) BPCL
Answer: b
Clarification: National Hydroelectric Power Corporation (NHPC), Northeast Electric Power Company (NEEPCO) and Satluj Jal Vidyut Nigam (SJVNL) are examples of public sector hydroelectric companies. Hindustan Petroleum deals with supply and trade of petrol and diesel. BHEL is a public sector company on electricals and electronics.

7. Maharashtra, Uttar Pradesh and Karnataka have ______ biomass power.
a) less than 100 KW
b) about 1 MW
c) more than 1 GW
d) more than 100 GW
Answer: c
Clarification: Maharashtra, Uttar Pradesh and Karnataka have more than 1 GW of biomass power. This power is grid interacted. These three states are leading in electricity generation from biomass.

8. What is the maximum conversion efficiency of thermal power plants?
a) Between 10 and 20%
b) 5%
c) Between 20 and 40%
d) Between 40 and 50%
Answer: d
Clarification: The maximum conversion efficiency of thermal power plants is around 45-46%. In a hot country like India, by reducing the inlet air temperature through absorption chiller the maximum conversion efficiency can be attained.

9. Industrial sector in India consumes ______ total commercial energy produced.
a) more than half of the
b) less than 10% of the
c) less than half of the
d) the amount as the domestic sector consumes from
Answer: a
Clarification: The industrial sector in India consumes about 56% — more than half of the total commercial energy produced. This sector includes energy intensive industries like aluminum, iron, textile, pulp and paper.

10. The industrial sector in India has a higher energy intensity as compared to that of developed countries.
a) True
b) False
Answer: a
Clarification: The industrial sector in India has a higher energy intensity as compared to that of developed countries. The energy intensity in India is about 3 times that of US and 4 times that of UK.

11. Why is the energy intensity of Indian industrial sector higher than that of the developed countries?
a) Because of less number of energy intensive industries
b) Because of lower population
c) Because of large number of energy intensive industries
d) Because of large population
Answer: c
Clarification: As compared to the developed countries, Indian industrial sector has a higher energy intensity. This is because of the large number of energy intensive industries like textile, pulp and paper.

12. How can energy consumption in industrial sector be reduced?
a) By not recycling
b) By using old and outdated technology
c) By wasting heat
d) By cascading and process control
Answer: d
Clarification: Energy consumption in industrial sector can be reduced by cascading, improvement in process and process control. Recycling and updating technology also contributes towards reduction in energy consumption.

13. What does the energy consumption in Indian transport sector depend on?
a) Fuel price
b) Driver
c) Ergonomics
d) Fuel tank
Answer: a
Clarification: Energy consumption in Indian transportation sector depends on fuel price, vehicle efficiency, infrastructure quality, etc. It does not depend on ergonomics and the fuel tank.

14. Kerosene is used for cooking and lighting lamps in rural parts of India.
a) True
b) False
Answer: a
Clarification: Kerosene is used for cooking and lighting lamps in rural parts of India. Apart from kerosene, animal waste, firewood and other crop waste are also used for various domestic purposes.

15. Air conditioning is the major electricity consumer in commercial sector.
a) True
b) False
Answer: a
Clarification: Air conditioning, fans and lighting are the major electricity consumers in commercial sector. Sometimes, computer servers and other domestic appliances like water heaters also compete for the top spot in energy consumption.

Solar Energy Multiple Choice Questions on “Solar Passive Space – Heating and Cooling Systems”.

1. What is solar heating and cooling?
a) Use solar energy to regulate the internal temperature of a given space
b) Use solar energy to regulate the temperature of environment
c) Use solar energy to monotonically increase the internal temperature of a given space
d) Use solar energy to monotonically decrease the temperature of a given space

Answer: a
Clarification: Passive solar heating and cooling, also called as passive solar design uses solar energy to regulate the internal temperature of a given space. The space is essentially some kind of closed/isolated area.

2. Which of the following is used to regulate temperature in solar heating and cooling system?
a) Air conditioners
b) Specific building systems
c) Water heaters
d) Room heaters

Answer: b
Clarification: Building systems designed specifically for a solar heating and cooling system is used to regulate the temperature of a given space. It could be done with the help of temperature controlling systems like an air conditioner embedded into the building.

3. Which of the following is not used in a passive solar heating/cooling system?
a) Building walls
b) Building roofs
c) Air conditioners
d) Building floors

Answer: c
Clarification: Air conditioners are not used in a passive solar heating and cooling system. This is simply because the system is passive. Wall, floors and roofs are included in a passive system?

4. What is a passive solar heating and cooling system?
a) Uses building design with mechanical systems to regulate the temperature outside a given space
b) Uses building design with mechanical systems to monotonically increase the temperature inside a given space
c) Uses building design without any solar heating (and cooling) system to regulate the temperature outside a given space
d) Uses building design without any solar heating (and cooling) system to regulate the temperature inside a given space

Answer: d
Clarification: As the name suggests, a passive solar heating and cooling system does not use any kind of active system. Instead, it uses building design without any solar heating (and cooling) system to regulate the temperature inside a given space.

5. Which of the following is extremely important with respect to a passive solar heating and cooling system?
a) Materials used to construct the building
b) Electrical systems used to perform heating/cooling operation
c) Mechanical systems used to perform heating/cooling operation
d) Material used to build heating/cooling systems

Answer: a
Clarification: A passive solar heating and cooling system does not consist of any active element. Hence, materials used to construct the building plays a major role in regulating the amount of heat trapped within the room.

6. Which of the following is an example of passive solar technology?
a) Photovoltaic
b) Solar furnace
c) Active solar water heating systems
d) Solar thermo-mechanical systems

Answer: b
Clarification: Solar furnace is a well known example of passive solar technology. It uses concentrated solar power to generate high temperatures for industrial purposes. Active solar water heating systems and solar thermo-mechanical systems are active systems.

7. What is a sunroom?
a) A room with a sun fitted inside it
b) A room that does not allow sunlight to pass through it
c) A room that transmits a lot of sunlight and has a scenic view
d) A room that does not pass sunlight and has a scenic view

Answer: c
Clarification: A sunroom, also known as a solarium is a room that permits a lot of sunlight through it. It also has a beautiful scenic view for recreational purposes. This is an example of a passive solar technology.

8. Which of the following process is involved in heat transfer through building?
a) Seebeck effect
b) Peltier effect
c) Hall effect
d) Conduction

Answer: d
Clarification: Heat transfer in buildings occurs through conduction, convection and radiation. Seebeck effect and Peltier effect are about an electric potential difference due to thermal gradient and Hall effect are not related to heat transfer.

9. Which part of a house receives majority of solar radiation?
a) Roof
b) Side walls
c) Floor
d) Doors

Answer: a
Clarification: When compared to side walls, floor and doors, roofs receive majority of solar radiation. The heat from sun flows into the building mainly through radiation and supported by convection and conduction.

10. Which of the following is a site-specific design consideration for a passive solar heating and cooling system?
a) Orientation of the building
b) Latitude
c) Building window size
d) Placement of rooms

Answer: b
Clarification: Site specific design considerations are dependent on the location of the site. Hence, latitude, sun path and insolation are some examples of site-specific design considerations.

11. Which of the following is a design element for residential buildings in temperate and tropical climates?
a) Latitude
b) Diurnal variations in temperature
c) Using thermal mass to store excess solar energy during winter
d) Obstacles

Answer: c
Clarification: Using thermal mass to store excess solar energy during winter is a design element for residential buildings in temperate and tropical climates. Thermal mass is a property of the mass of a building to store heat. Latitude, obstacles and diurnal variations in temperature are site-specific design considerations.

12. A building with excessive glass cover ______
a) results in freezing
b) results in a pleasant temperature within the building
c) damages the building material
d) results in overheating

Answer: d
Clarification: A building with excessive glass cover results in overheating. This is basically due to trapping of heat within the building and is explained by greenhouse effect. It will not result in freezing.

13. A solar roof constructed on a building uses water stored ______ to temper hot and cold internal temperatures of the building.
a) on building roofs
b) on building walls
c) beneath building floors
d) on an auxiliary building

Answer: a
Clarification: A solar roof constructed on a building uses water stored on building roofs to temper hot and cold internal temperatures of the building. It is also called as roof pond passive solar heating system and is usually deployed in desert environments.

14. A “cool roof” uses reflective surfaces.
a) False
b) True

Answer: a
Clarification: A “cool roof” uses reflective surfaces. This is to ensure that major amount of the incident solar radiation is reflected back and the temperature within the building is maintained. Green roof is another variation that uses vegetation instead of reflective surfaces.