Category: Renewable Energy Objective Questions

Solar Energy MCQs on “Solar Thermo-Mechanical Systems -2”.

1. How does an ideal Rankine cycle work?
a) Heat-addition process does not occur at constant temperature
b) Heat-addition process occurs at temperature
c) Heat-addition process does not occur at constant pressure
d) Heat-addition process occurs at constant pressure
Answer: a
Clarification: Like Carnot cycle, Rankine cycle is a heat engine phase cycle. It determines how working fluid is used to convert energy from one form to another. The heat-addition process in Rankine cycle does not occur at constant temperature.

2. Which of the following best describes the process of an ideal Rankine cycle?
a) Working fluid is heated in boiler → exhaust vapour is condensed → vapour runs the turbine → liquid residue is pumped back into boiler
b) Working fluid is heated in boiler → vapour runs the turbine → exhaust vapour is condensed → liquid residue is pumped back into boiler
c) Vapour runs the turbine → working fluid is heated in boiler → exhaust vapour is condensed → liquid residue is pumped back into boiler
d) Exhaust vapour is condensed → Working fluid is heated in boiler → vapour runs the turbine → liquid residue is pumped back into boiler
Answer: b
Clarification: In an ideal Rankine cycle, the working fluid is heated in boiler and converted to vapours which is used to run the turbine. The exhaust vapours from the turbine is condensed to form a liquid residue which is pumped back into the boiler to complete the cycle.

3. Why is the efficiency of Rankine cycle less than that of Carnot cycle?
a) Because of the working fluid
b) Because of the turbines
c) Because all the heat is not supplied at upper temperatures
d) Because all the heat is supplied at upper temperatures
Answer: c
Clarification: The efficiency of Rankine cycle is less than that of Carnot cycle because all the heat is not supplied at upper (higher) temperatures. However, is has a high work ratio and its steam consumption is less than Carnot cycle.

4. How can the efficiency of Rankine cycle be improved?
a) By supplying heat at higher temperatures
b) By supplying heat at lower temperatures
c) By rejecting more heat
d) By using a part of rejected heat
Answer: d
Clarification: Rankine cycle has lower efficiency that Carnot cycle because all the heat is not supplied at upper temperatures. The efficiency of Rankine cycle can be improved by using a part of rejected heat in heating the liquid.

5. How does Stirling cycle differ from Carnot cycle?
a) The two adiabatic steps in Carnot cycle are replaced by two constant volume steps
b) The two adiabatic steps in Carnot cycle are replaced by two constant temperature steps
c) The two isothermal steps in Carnot cycle are replaced by two constant volume steps
d) The two isobaric steps in Carnot cycle are replaced by two constant volume steps
Answer: a
Clarification: The working of Stirling cycle is similar to that of Carnot cycle except for two steps. The two adiabatic steps in Carnot cycle are replaced by two constant volume steps.

6. In Stirling cycle, the heat addition and rejection take place at _________
a) constant pressure
b) constant temperature
c) two different temperatures
d) multiple pressures
Answer: b
Clarification: In Stirling cycle, the heat addition and rejection take place at constant temperatures. A suitable gas or air is used as working fluid and the turbine, compressor and heat exchanger are closely coupled.

7. Which of the following best describes Brayton Cycle?
a) Exhaust gas → hot compressed gas → expands through turbine by doing work → heat exchanger → rejection of heat → gas goes to compressor
b) Exhaust gas → hot compressed gas → expands through turbine by doing work → heat exchanger → gas goes to compressor → rejection of heat
c) Hot compressed gas →expands through turbine by doing work → exhaust gas → heat exchanger → rejection of heat → gas goes to compressor
d) Heat exchanger → exhaust gas → hot compressed gas → expands through turbine by doing work → gas goes to compressor → rejection of heat
Answer: c
Clarification: In Brayton Cycle, the hot compressed gas expands through the turbine by doing work. The exhaust gas from the turbine is passed into heat exchanger to reject heat. Then this gas is fed into the compressor to be compressed and used again.

8. Which of the following governs the efficiency of any practical solar thermo-mechanical system?
a) Photovoltaics
b) Rankine Cycle
c) Brayton Cycle
d) Properties of working fluid
Answer: d
Clarification: Properties of working fluid govern the efficiency of any practical solar thermo-mechanical system. Rankine and Brayton Cycles are techniques to implement heat engines to convert the input energy into a usable output energy.

9. The choice of working fluid depends on the operating temperatures in the boiler.
a) True
b) False
Answer: a
Clarification: The choice of working fluid depends on the operating temperatures in the boiler. It also depends on the condenser being used and the type of heat engine.

10. What is the main problem in a solar thermo-mechanical system as the collection (operating) temperature increases?
a) Efficiency of collection system and engine decreases
b) Efficiency of collection system decreases but engine efficiency increases
c) Efficiency of collection system and engine increases
d) Efficiency of collection system increases and engine efficiency decreases
Answer: b
Clarification: The main problem in a solar thermo-mechanical system is that as the collection (operation) temperature increases efficiency of the collection system decreases. However, the engine efficiency increases as the temperature of working fluid increases.

11. The practical heat engine _______ theoretical efficiency.
a) has greater efficiency than
b) has the same efficiency as that of
c) has lesser efficiency as compared to the
d) always has minimum efficiency equal to that of
Answer: c
Clarification: The practical heat engine used in solar thermo-mechanical systems always has lesser efficiency as compared to the theoretical efficiency. It can never exceed the theoretical limit due to practical limitations.

12. What is the bare minimum requirement for the construction materials used in solar thermo-mechanical systems?
a) Contaminate the working fluid
b) Withstand heat from the working fluid
c) Withstand pressure from the working fluid
d) Withstand both, heat and pressure from working fluid
Answer: d
Clarification: The bare minimum requirement from the construction materials used in a solar thermo-mechanical system is that they withstand both, heat and pressure from the working fluid. The materials should not contaminate the fluid.

13. Which of the following affects the installation of a solar thermo-mechanical system?
a) Availability of land
b) Availability of photovoltaics
c) Availability of sunlight and clouds
d) Availability of rain
Answer: a
Clarification: Availability of land affects the installation of solar thermo-mechanical system. Sunlight is important but most places on earth receive sunlight. Clouds and rain are a hinderance to the system.

14. What is the minimum vapour pressure (in kPa) of the working fluid to drive a turbine?
a) 300
b) 700
c) 100
d) 50
Answer: b
Clarification: The minimum vapour pressure of the working fluid to drive a turbine is 700 kPa. The preferred vapour pressure 2000kPa for useful work.

15. Organic vapours are used small plants and low powered solar thermo-mechanical systems.
a) True
b) False
Answer: a
Clarification: Organic vapours are used small plants and low powered solar thermo-mechanical systems. This is simply driven by the demands and finances.

MCQs on all areas of Solar Energy,
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Biomass Energy Problems on “Solar Radiation on Inclined Plane Surface”.

1. When is the power density of the absorbing surface equal to the incident sunlight?
a) Absorbing surface and incident sunlight are perpendicular to each other
b) Absorbing surface and incident sunlight are parallel to each other
c) Absorbing surface and incident sunlight are inclined at an acute angle to each other
d) Absorbing surface and incident sunlight are inclined at an obtuse angle to each other

Answer: d
Clarification: Net power received from incident sunlight depends on two things – the power contained in the sunlight and the angle of the receiver with respect to the incident sunlight. Incident power equals the received power when the receiver is perpendicular to the incident sunlight.

2. For a fixed receiver, incident power density and received power density are always equal.
a) True
b) False

Answer: b
Clarification: For a fixed receiver, incident power density and received power density are not equal always. In fact, the net received power is often less than the incident power as the angle between the sun and the receiver changes continuously.

3. What is direct solar radiation?
a) Radiation scattered by molecules
b) Radiation reflected from an obstacle
c) Radiation traveling on a straight line from sun to earth
d) Sum of diffused and reflected radiation energies

Answer: c
Clarification: Direct solar radiation is that radiation which travels in a straight line from the sun. It travels to the earth without deviating from its path due to obstacles.

4. What is diffused solar radiation?
a) Sum of direct and reflected radiation energies
b) Radiation reflected from an obstacle
c) Radiation traveling on a straight line from sun to earth
d) Radiation scattered by molecules

Answer: d
Clarification: Diffused solar radiation is that radiation which has been scattered by molecules and particles in atmosphere. Though it deviates from its initial path, it does travel down to the earth.

5. Which of the following is tried to maximized in tilted receivers (panels)?
a) Direct radiation
b) Diffused radiation
c) Reflected radiation
d) Diffracted radiation

Answer: a
Clarification: Receivers are tilted to maximize the collection of direct solar radiation from the sun. The tilt tries to ensure that the receivers are perpendicular to the direct radiation. It accounts for the continuous change in angle between the sun and the receiver.

6. When receivers (panels) are laid horizontally, they usually collect _______
a) Direct radiation
b) Diffused radiation
c) Deflected radiation
d) Heat

Answer: b
Clarification: When solar receivers (panels) are laid horizontally, they usually collect diffused radiation. This is because diffused radiation is equally distributed throughout the sky and hence can easily be gathered.

7. More the tilt in receivers (panels), larger amounts of diffused radiation is collected.
a) False
b) True

Answer: a
Clarification: More the tilt in receivers, larger amounts of direct radiation is collected. As the tilt increases, the amount of diffused radiation received considerably reduces.

8. What is reflected solar radiation?
a) Sum of direct and reflected radiation energies
b) Radiation reflected from an atmospheric obstacle
c) Radiation traveling on a straight line from sun to earth
d) Radiation reflected from a non-atmospheric obstacle

Answer: d
Clarification: Reflected solar radiation is that sunlight/radiation that is reflected from a non-atmospheric obstacle. The obstacles could be trees, ground, light poles, cars, etc. They do not contribute significantly towards electricity generation from solar panels.

9. Reflected solar radiation is used in _______
a) Snowy regions
b) Temperate region
c) Equatorial region
d) Tropical region

Answer: a
Clarification: Generally, reflected solar radiation does contribute significantly towards electricity generation. However, energy from reflected radiation is harvested in snowy regions as fresh snow reflects about 80-90% of the incident radiation.

10. What is global insolation?
a) Direct radiation + diffused radiation
b) Diffused radiation – direct radiation
c) Direct radiation + diffused radiation + reflected radiation
d) Reflected radiation * direct radiation

Answer: c
Clarification: Global insolation or total insolation is the sum of the radiation received by earth from sun. It is nothing but the sum of direct radiation, diffused radiation and reflected radiation. This is used as a reference for the insolation at some tilt.

11. What is normal radiation?
a) Direct radiation
b) Sun’s radiation and striking surface are perpendicular to each other
c) Incident solar radiation and striking surface are perpendicular to each other
d) Global insolation – direct radiation

Answer: b
Clarification: Normal radiation describes the radiation that strikes a surface that is perpendicular to the sun’s radiation. It is not same as direct radiation as the it does not talk about the incident radiation. It may so happen that normal radiation and direct radiation may be the same at some tilt.

12. What is hour angle of the sun?
a) Angle of radiation with earth’s surface
b) Angle between the hands of sun dial
c) Angle made by the sun’s rays with moon’s surface
d) Orientation of earth with respect to sun

Answer: d
Clarification: Hour angle of sun is defined as the actual orientation of earth with respect to the sun. Mathematically, it is calculated by converting earth’s one rotation in degrees and dividing it by the time taken – 360/24 = 15 degrees/h.

13. What is solar intensity?
a) Amount of outgoing solar energy
b) Amount of incoming solar energy on a plane surface
c) Amount of outgoing solar energy on a plane surface per unit time
d) Amount of incoming solar energy on a plane surface per unit time per unit area

Answer: d
Clarification: Solar intensity is defined as the amount of incoming solar energy on a plane surface per unit time per unit area. It is a weighted average of the full radiation and is equal to 1367 Watt/square meter.

14. What is solar azimuth angle?
a) Orientation of earth with respect to sun
b) Orientation of moon with respect to sun
c) Angle of radiation with earth’s surface
d) Angular distance between zero azimuth and sun’s projection on ground

Answer: d
Clarification: Solar azimuth angle is defined as the angular distance between zero azimuth and the projection of the line of sight to sun on the ground. Zero azimuth is a line due north or due south. Azimuth angle is measured clockwise from zero azimuth.

15. Diffuse radiation models can be classified into ________ and __________
a) direct and reflective
b) adiabatic and isotropic
c) isotropic and anisotropic
d) anisotropic and adiabatic

Answer: c
Clarification: Diffuse radiation models can be classified into isotropic and anisotropic. Isotropic models of diffuse radiation model diffuse radiation intensity by assuming uniform distribution throughout the sky (medium). Anisotropic models include suitable modules that are used to represent regions of increased (varied) diffuse radiation.

Ocean Energy Multiple Choice Questions on “Tidal Energy – 1”.

1. What is tidal power?
a) Energy from tides
b) Energy from water
c) Energy from moon
d) Energy from sun

Answer: a
Clarification: Tidal power converts the energy from tides to usable forms. Though tides are water, it is not the same as the energy harnessed from a flowing river. Tides are caused due to moon.

2. Which of the following categories does tidal power fall into?
a) Hydrothermal
b) Hydropower
c) Solar
d) Wind

Answer: b
Clarification: Tidal power comes under the category of hydropower. Hydrothermal is basically energy harnessed from hot water/steam found in geothermal sites. Solar and wind are not related to water.

3. What is/are the cause(s) of tides?
a) Gravitational pull of moon
b) Gravitational pull of moon and sun
c) Gravitational pull of sun and moon and rotation of earth
d) Gravitational pull of sun

Answer: c
Clarification: Tides are caused by the gravitational pull of moon, sun and the rotation of earth. It is the cumulative effect of all the three factors. No single factor individually dominates the other.

4. What is the minimum height of tides required for harnessing tidal energy economically?
a) 1 foot
b) 5 feet
c) 8 feet
d) 10 feet

Answer: d
Clarification: To harness tidal energy economically, the minimum height of the tides should be 10 feet. Most of the plants harness the tidal energy to generate electricity which is either used in remote locations or sent to the grid.

5. In terms of predictability, tidal energy _____ solar and wind.
a) is more predictable than
b) is less predictable than
c) has similar predictability like
d) cannot be predicted unlike

Answer: a
Clarification: In terms of predictability, tidal energy is more predictable than solar and wind. This because of its origins – gravitational forces and earth’s rotation. Intensity of sunlight and wind speeds vary greatly within a day unlike the tides.

6. Tidal barrage is similar to ______
a) wind plant
b) dam
c) wind turbines
d) coal plant

Answer: b
Clarification: Tidal barrage is similar to a dam. As the name suggests, a barrage (barrier) is constructed across an inlet of an ocean bay to harness the energy.

7. Which of the following best describes the working of a tidal barrage for an incoming tide?
a) Incoming tides → generator → barrage → basin
b) Incoming tides → basin → generator → barrage
c) Incoming tides → barrage → basin → generator
d) Generator → barrage → basin → incoming tides

Answer: c
Clarification: The incoming tides flow through the barrage into the basin. Once the basin is filled, the water is emptied by allowing it to pass through an electric generator thereby generating electricity.

8. Which of the following best describes the working of tidal barrage for outgoing tides?
a) Generator → basin → ocean → outgoing tide
b) Generator → ocean → basin → outgoing tide
c) Ocean → generator → basin → outgoing tide
d) Outgoing tide → generator → basin → ocean

Answer: d
Clarification: The outgoing tides flow through the generator which converts the kinetic energy into electrical energy. The water is then emptied into the ocean via a separate basin.

9. Tidal barrages are a two-way tidal power system.
a) True
b) False

Answer: a
Clarification: Tidal barrages are a two-way power system. This is because they use both, the incoming and the outgoing tides to generate electricity. The water flow is controlled by sluice gates.

10. Which of the following is a potential problem of a tidal barrage?
a) Impacts on deep sea/ocean marine life
b) Impacts on estuaries of the tidal basin
c) A two-way tidal power system
d) Decrease in turbidity

Answer: b
Clarification: One of the main problems that a tidal barrage can cause is the destruction of estuaries of the tidal basin. Tidal barrages also increase the turbidity of the water near the basin. They don’t affect the deep sea marine life.

11. Which of the following tidal barrages has the largest capacity to generate electricity?
a) La Rance
b) Annapolis Royal
c) The Sihwa Lake Tidal Power Station
d) Russian tidal plants

Answer: c
Clarification: The Sihwa Lake Tidal Power Station in South Korea has the largest capacity to generate electricity. The tidal plant in La Rance, France is the oldest and has the second largest capacity. Next comes the tidal power plant in Annapolis Royal in Nova Scotia.

12. What are the three ways to harness tidal energy?
a) Tidal streams, tidal barrages and wind
b) Tidal barrages, wind and sun
c) Tidal lagoons, river streams and geothermal reservoirs
d) Tidal lagoons, tidal streams and tidal barrages

Answer: d
Clarification: The three different ways to harness tidal energy are tidal streams, tidal barrages and tidal lagoons. Geothermal reservoirs, wind and sun are not tidal resources.

13. The United States has an economical tidal power plant.
a) True
b) False

Answer: a
Clarification: At the very best, the United States does not have an economical tidal power. China, France, England, Canada and Russia are some of the popular countries known to harness tidal energy.

14. What is a tidal stream?
a) A river streams
b) A fast-flowing body of water due to tides
c) A fast-flowing body of water deposited into ocean
d) A fast-flowing body of water due to winds

Answer: b
Clarification: A tidal stream is a fast-flowing body of water created by tides. It is not the same as a river stream. When compared to a river stream it has a much higher kinetic energy.

15. Tidal generators produce steady and reliable stream of electricity.
a) True
b) False

Answer: a
Clarification: Tidal generators produce steady and reliable stream of electricity. This is because unlike sun’s intensity and wind speeds which vary over short duration of time, tides are predictable and stable.

Renewable Energy Multiple Choice Questions on “Environmental Aspects of Energy – 2”.

1. Which of the following is the cleanest fossil fuel?
a) Natural gas
b) Petrol
c) Petroleum
d) Coal
Answer: a
Clarification: Natural gas is often described as the cleanest fossil fuel. Petroleum is a raw form of fossil fuel found in oceans and seas. Petrol is a processed product of petroleum.

2. What is IPCC?
a) A government organization that provides scientific information regarding climate change and its effects
b) An intergovernmental body of UN that provides scientific information regarding climate change and its effects
c) An intergovernmental organization that provides scientific information regarding climate change and its effects
d) A private company that sells scientific information regarding climate change
Answer: b
Clarification: IPCC stands for “Intergovernmental Panel on Climate Change”. It is an intergovernmental body of UN that provides scientific information regarding climate change and its effects. It is non-profit organization.

3. What is the objective of the main international treaty on climate change?
a) To provide scientific information on climate change
b) To destabilise the greenhouse gas concentrations so that anthropogenic actions interfere with the climate system
c) To stabilise the greenhouse gas concentrations so that anthropogenic actions do not interfere with the climate system
d) To bring peace between all countries
Answer: c
Clarification: The objective of the main international treaty on climate is to stabilise the greenhouse gas concentrations so that anthropogenic actions do not interfere with the climate system. The treaty itself does not provide information on climate change.

4. What is the aim of Paris Agreement in 2015? Note that C indicates Celsius.
a) To keep the decrease in global average temperature to below 2 degree C
b) To keep the decrease in global average temperature to above 2 degree C
c) To keep the increase in global average temperature to above 2 degree C
d) To keep the increase in global average temperature to below 2 degree C
Answer: d
Clarification: The Paris Agreement is an agreement within United Nations Framework Convention on Climate Change dealing with greenhouse gas emissions. Its long term goal is to keep the decrease in global average temperature to below 2 degree C.

5. Which of the following IPCC assessment reports was a critical input in Paris Agreement?
a) Fifth Assessment Report
b) First Assessment Report
c) Second Assessment Report
d) Tenth Assessment Report
Answer: a
Clarification: IPCC’s fifth Assessment Report (AR) was a critical scientific input into Paris Agreement held in 2015. The AR5 report was developed through a scoping process involving climate change experts from all relevant disciplines.

6. Where is the ozone hole located?
a) Asia
b) Antarctica
c) Europe
d) America
Answer: b
Clarification: The ozone hole is located over Antarctica. It was and still is the largest observed ozone hole. It was caused due continuous emissions of CFCs and freons.

7. What is main potential water pollutant from a geothermal reservoir?
a) Carbon
b) Silicon
c) Sulphur
d) Nitrogen
Answer: c
Clarification: The main water pollutant from a geothermal reservoir is sulphur. This is because underground reservoirs contain large amounts of sulphur and other minerals.

8. How does a geothermal plant prevent the leakage of sulphur into environment?
a) By trapping it inside the reservoir during extraction of hot water
b) By trapping it inside the reservoir before extraction of hot water
c) By disposing it into water bodies
d) By using a closed-loop water system
Answer: d
Clarification: Most geothermal plants prevent leakage of sulphur and other minerals into the environment by using a closed-loop water system. The spent water is pumped directly back into the geothermal reservoir.

9. Which of the following gases is commonly emitted into the atmosphere from an open-loop geothermal system?
a) Hydrogen sulphide
b) Hydrogen
c) Carbon
d) Silicon
Answer: a
Clarification: Hydrogen sulphide is commonly emitted into the atmosphere from an open-loop geothermal system. Carbon and silicon are not gases. Even if hydrogen is emitted it is not the most common one.

10. How does hydrogen sulphide from geothermal plants contribute towards pollution?
a) By reacting with acidic gases to cleans the precipitating rainwater
b) By forming sulphur dioxide
c) By changing into one of the noble gases
d) By reacting with ozone
Answer: b
Clarification: Hydrogen sulphide reacts and changes into sulphur dioxide. Sulphur dioxide contributes to the formation of acid rain which is harmful to the environment.

11. Which of the following is the largest emitter of sulphur dioxide?
a) Geothermal plants
b) Photosynthesis
c) Coal plants
d) Respiration
Answer: c
Clarification: If not the coal plants are one of the largest emitters of sulphur dioxide. Photosynthesis releases oxygen and respiration releases carbon dioxide. Though geothermal plants release hydrogen sulphide which converts into sulphur dioxide, their contribution is negligible when compared to coal plants.

12. Land requirement of a geothermal plant depends on _______
a) greenhouse gas emissions
b) hydrogen sulphide emissions
c) the wildlife
d) amount of power capacity
Answer: d
Clarification: Land requirement of a geothermal plant depends on the amount of power capacity. It also depends on other factors like the substation and the type of energy conversion system.

13. Which of the following is one of the major problems caused by a geothermal plant to land?
a) Land subsidence
b) Land fertilisation
c) Reservoir cleansing
d) Noble gas emissions
Answer: a
Clarification: Land subsidence is one of the major problems caused by a geothermal plant to land. It is basically the sinking of land surface due to various activities in the plant and reservoir. Geothermal plants neither fertilise the land nor emit noble gases.

14. Photovoltaic manufacturing requires hazardous materials.
a) True
b) False
Answer: a
Clarification: Manufacturing of photovoltaics require hazardous materials like arsenic and cadmium. Consumption of such metals even in small amounts could be deadly for the workers in the factory.

15. Life cycle assessment is a good indicator of the net environmental impact of any technology.
a) True
b) False
Answer: a
Clarification: Life cycle assessment is a good indicator of the net environmental impact of any technology including renewable energy. This is because it studies the environmental impacts of the processes involved, materials used to manufacture the technology and the manufacturing processes of the materials.

Solar Energy Interview Questions on “Empirical Equations for Estimating Solar Radiation Availability on Horizontal Surface for Cloudy Skies”.

1. What is the relationship between insolation and cloud cover in sky?
a) Inverse
b) Directly proportional
c) Square
d) Exponential

Answer: a
Clarification: From ancient time, people knew the relationship between sunshine and cloud cover. There is an inverse relationship between insolation and the amount of sky covered by clouds.

2. Which of the following is a reason for inverse relationship between insolation and cloud cover in sky?
a) Sunshine duration records are caused by sun being obstructed by transparent cloud cover
b) Sunshine duration records are caused by sun being obstructed by opaque cloud cover
c) Sunshine duration records are caused by sunshine being transmitted through opaque cloud cover
d) Sunshine duration records are caused by sun being obstructed by cloud cover

Answer: b
Clarification: There is an inverse relationship between insolation and cloud cover in sky. This is because of sunshine duration records are caused by sun being obstructed by transparent cloud cover.

3. Which does Angstrom-Savinov formula tell?
a) Relationship between local solar radiation and global cloudiness
b) Relationship between local solar radiation and local cloudiness
c) Relationship between global solar radiation and mean cloudiness
d) Relationship between global solar radiation and global cloudiness

Answer: c
Clarification: Angstrom-Savinov formula is a relationship between global solar radiation (H) and mean cloudiness (C). It is given by mathematical relationship, H=H₀[1−(1−k)C].

4. What does the constant “k” signify in the Angstrom-Savinov formula?
a) Global solar radiation
b) Mean cloudiness
c) Reflection of solar radiation within clouds
d) Transmission of solar radiation within clouds

Answer: d
Clarification: The constant “k” signifies the transmission of solar radiation within clouds. It is defined to account for the partial and practical transmission of solar radiation through clouds.

5. The constant “k” in Angstrom-Savinov formula depends on ________
a) latitude of the location
b) longitude of the location
c) solar radiation
d) cloud opacity

Answer: a
Clarification: The constant “k” accounts for transmission of solar radiation through clouds. It depends on the latitude of the location. It does not depend on the solar radiation and cloud capacity.

6. How does the constant “k” in Angstrom-Savinov vary in high and low latitudes?
a) Between 0.55 in high latitudes and 0.22 in low latitudes
b) Between 0.55 in high latitudes and 0.33 in low latitudes
c) Between 0.33 in high latitudes and 0.55 in low latitudes
d) Between 0 in high latitudes and 0.9 in low latitudes

Answer: b
Clarification: The constant “k” in Angstrom-Savinov has a range from 0.33 to 0.55. It varies between 0.55 in high latitudes and 0.33 in low latitudes.

7. Which of the following models uses linear regression to estimate solar radiation from sunshine duration?
a) Angstrom-Savinov
b) Ertekin and Yladtz
c) Anstrom-Prescott
d) Sen

Answer: c
Clarification: Anstrom-Prescott model uses linear regression to estimate solar radiation from sunshine duration. H/H₀=a+b*(S/S₀) is the regression equation. H is global radiation and S is the sunshine duration.

8. Akinoglu and Fcevit uses a _______ to estimate solar radiation.
a) linear model
b) power model
c) exponential model
d) quadratic model

Answer: d
Clarification: Akinoglu and Fcevit uses a quadratic model to estimate solar radiation. Like Angstom-Savinov, it also estimates solar radiation from sunshine duration.

9. How is an empirical model developed?
a) From data acquired via sensors or measuring instruments
b) From theoretical analysis
c) From deep learning
d) From trial and error

Answer: a
Clarification: Empirical models of any system is developed from data acquired via sensors or measuring instruments. The developers decide the variables and the output and perform various numerical analysis to formulate a relationship.

10. What does the ratio of global solar radiation (H) and estimated daily global radiation for cloudless sky (H₀) indicate?
a) Solar radiation transmission ratio
b) Clearness index
c) Solar radiation reflection percentage
d) Turbidity

Answer: b
Clarification: The ratio of global solar radiation (H) and estimated daily global radiation for cloudless sky (H₀) indicates clearness index. It neither indicates solar radiation transmission ratio nor does it indicate turbidity. Solar radiation reflection percentage is indicated by albedo.

11. Which of the following is important during data acquisition from measuring instruments? Assume that details about data to be collected is known.
a) Type of data
b) Materials used to manufacture measuring instruments
c) Location, environment and characteristics of measuring instrument
d) Brand of measuring instruments

Answer: c
Clarification: Assuming that details about the data to be collected is known, location, environment and characteristics of measuring instrument is important. This is because instruments can give different values under different conditions. Basically, data acquisition procedure should be consistent and authentic.

12. Which of the following statistical indicator is used to evaluate any type of model?
a) mean
b) median
c) error
d) root mean square error

Answer: d
Clarification: Root mean square error is a commonly used statistical indicator to evaluate any type of model. It basically describes the mean error between simulated/measured/observed values and the true values.

13. Why do ground-based observers overestimate overcast cloud cover?
a) Clouds appear to fill large area of sky when near horizon
b) Clouds appear to fill large area of sky when far from horizon
c) Clouds appear to fill small area of sky when near horizon
d) Clouds appear to fill small area of sky when far from horizon

Answer: a
Clarification: Ground-based observers tend to overestimate overcast cloud covers. This is because clouds with vertical extents appear to fill a greater area of sky when located near the horizon than when they are overhead.

14. Reduction of error between simulated values and the true values increases accuracy of the empirical model.
a) True
b) False

Answer: a
Clarification: Reduction of error between simulated values and the true values increases accuracy of the empirical model. This is because decrement in error indicates that simulated values are moving closer to true/desired values.

15. Cloud cover estimation is free from error.
a) True
b) False

Answer: b
Clarification: Like any other estimation, cloud cover estimation is not free from errors. For instance, a small hole in the cloud could remain open for a long period of time thereby allowing more sunlight to pass through than estimated.

Wind Energy Multiple Choice Questions on “Origin of Winds – 1”.

1. Which of the following provides energy for winds to blow naturally?
a) Sun
b) Water
c) Man
d) Food

Answer: a
Clarification: The energy that drives winds originates from the sun’s heat received along with sunlight. The heat creates areas of low pressure and high pressure, thereby causing winds to blow. Wind is abiotic and does not need food. Any wind blowing due to man is artificial. Water aids in magnifying a low or high pressure area but does not cause winds.

2. Wind flows from _______ pressure area to ________ pressure area.
a) high, high
b) high, low
c) low, high
d) low, low

Answer: b
Clarification: Wind always flows from a high pressure area to a low pressure area. The difference in pressures causes wind to flow from in a direction. Winds originate from the heat received by sun which heat’s the earth’s surface unevenly resulting in a pressure difference.

3. What is a gust?
a) No change in wind speed
b) A brief decrease in wind speed for a very long period of time
c) A brief increase in wind speed for a very short period of time
d) A brief increase in wind speed for a very long period of time

Answer: c
Clarification: A gust or a wind gust is a brief increase in wind speed for a very short period of time, typically less than 20 seconds and has a transient characteristic unlike a squall.

4. What is a squall?
a) A sudden, sharp increase in wind speed lasting for a few hours
b) A sudden, sharp decrease in wind speed lasting for a few minutes
c) A sudden, sharp decrease in wind speed lasting for a few hours
d) A sudden, sharp increase in wind speed lasting for a few minutes

Answer: d
Clarification: A squall is a sudden, sharp increase in wind speed lasting for a few minutes. Squalls occur during rain showers, thunderstorms or heavy snow fall.

5. A windstorm _______
a) is strong enough to cause property damage
b) is not stronger than gust
c) does not exist
d) is not strong enough to cause property damage

Answer: a
Clarification: A windstorm consists of winds strong enough to cause property damage like uprooting of trees and damaging erected buildings. Wind speed in a typical windstorm exceeds 55km/s and can be extremely detrimental.

6. What are planetary or prevailing winds?
a) Winds not blowing from one latitude to another
b) Winds blowing from one latitude to another
c) Gusts
d) Winds that do not cover large areas of earth

Answer: b
Clarification: Planetary winds are winds that blow from one latitude to another throughout the year due to latitudinal differences in air pressure. They cover large areas of earth.

7. Which of the following are the two most important planetary winds?
a) Hosting
b) Trades and economics
c) Trade winds and westerly winds
d) Deployment

Answer: c
Clarification: Trade winds and westerly winds are the two most important planetary or prevailing winds. Other options – trade and economics, hosting and deployment are not related to winds.

8. What are trade winds?
a) Winds blowing from equatorial low pressure areas to sub-tropical high pressure areas
b) Winds that trade with each other
c) Winds blowing from equatorial high pressure areas to sub-tropical low pressure areas
d) Winds blowing from sub-tropical high pressure areas to equatorial low pressure areas

Answer: d
Clarification: Trade winds are extremely steady winds blowing from sub-tropical high pressure areas to equatorial low pressure areas. They maintain a constant direction throughout their course.

9. How does Coriolis effect trade winds in Northern Hemisphere?
a) Coriolis effect deflects trade winds to the right
b) Coriolis effect deflects trade winds to the left
c) Coriolis effect does not affect the trade winds in Northern Hemisphere
d) Coriolis effect only affects the trade winds in Southern Hemisphere

Answer: a
Clarification: Coriolis effect and Ferrel’s law disrupt the flow of trade winds from north to south and deflect them towards right in the Northern Hemisphere. Thus, they blow in a north east direction in the Northern Hemisphere.

10. How does Coriolis effect trade winds in Southern Hemisphere?
a) Coriolis effect deflects trade winds to the right
b) Coriolis effect deflects trade winds to the left
c) Coriolis effect does not affect the trade winds in Southern Hemisphere
d) Coriolis effect only affects the trade winds in Northern Hemisphere

Answer: b
Clarification: Coriolis effect and Ferrel’s law disrupt the flow of trade winds flowing from north to south and deflect them towards left in the Southern Hemisphere. Thus, they blow in a south east direction in the Southern Hemisphere.

11. Trade winds ______
a) do not maintain a constant direction but blow steadily
b) maintain a constant direction but do not blow steadily
c) maintain a constant direction and blow steadily
d) shrinking technique

Answer: c
Clarification: Trade winds are also called as tropical easterlies. They maintain the same direction and blow steadily in that direction. Shrinking technique is not related to winds.