Test: Sources of Energy - 4 - UPSC MCQ

Explanation:
The statement "Rotation of earth is responsible for wind to blow" is a Correct statement.
Here's a detailed explanation:
1. Coriolis Effect: The rotation of the Earth causes the Coriolis effect, which influences the movement of air masses and the formation of wind patterns.
2. Rotation and Wind Direction: Due to the Earth's rotation, different parts of the Earth's surface have different speeds. The equator rotates faster than the poles. This speed difference creates a pressure gradient, causing air to move from high pressure to low pressure areas, resulting in wind.
3. Trade Winds and Prevailing Westerlies: The rotation of the Earth also affects the direction of wind patterns. Near the equator, the trade winds blow from east to west, while in the mid-latitudes, the prevailing westerlies blow from west to east. These wind patterns are a result of the Coriolis effect caused by the Earth's rotation.
4. Global Circulation Patterns: The rotation of the Earth plays a significant role in the formation of global circulation patterns. The Hadley cell, Ferrel cell, and Polar cell are the main atmospheric circulation cells that exist due to the Earth's rotation and the resulting wind patterns.
5. Jet Streams: The rotation of the Earth also influences the formation and behavior of high-altitude jet streams. These fast-flowing, narrow air currents are primarily driven by the temperature and pressure differences caused by the Earth's rotation.
In conclusion, the statement that the rotation of the Earth is responsible for wind to blow is correct. The Earth's rotation causes the Coriolis effect, which affects wind patterns, direction, and the formation of atmospheric circulation cells.

Answer:

An environment-friendly fuel is one that has minimal negative impact on the environment, particularly in terms of combustion and its byproducts. To determine if a fuel is environmentally friendly, we need to consider the following factors:

Calorific value:

• A fuel's calorific value refers to the amount of heat energy it can produce when burned.


• An environment-friendly fuel does not necessarily have a lower calorific value, as it depends on the specific requirements and efficiency of the system it is being used in.

Combustion products:

• The combustion products of a fuel can have a significant impact on the environment.


• An environment-friendly fuel should produce combustion products that are non-poisonous.


• This means that the emissions should not contain harmful pollutants or toxins that can negatively affect air quality or human health.

Pollutants:

• Environmentally friendly fuels should have minimal pollutants in their combustion products.


• This means that the emissions should not contribute to air pollution or the greenhouse effect.


• Examples of pollutants include carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides (NOx), and particulate matter (PM).

Ash production:

• An environment-friendly fuel should produce minimal amounts of ash during combustion.


• Ash can be a byproduct of certain fuels and can pose disposal and environmental challenges.


• Reducing ash production can help minimize waste and environmental impact.

Conclusion:

Based on the given options, the correct answer is B: Its combustion products are non-poisonous. This criterion aligns with the concept of an environmentally friendly fuel as it emphasizes the importance of minimizing harm to both human health and the environment.

Potential Site for Harnessing Tidal Energy in India:
The potential site for harnessing tidal energy in India is the Gulf of Kutch in Gujarat.
- Gulf of Kutch in Gujarat:
- Located in the western state of Gujarat, the Gulf of Kutch offers a favorable location for tidal energy harnessing.
- The Gulf of Kutch experiences strong tidal currents due to its proximity to the Arabian Sea.
- The region has a significant tidal range, with high and low tides occurring at regular intervals.
- The presence of narrow channels and creeks in the gulf helps to enhance the tidal energy potential.
- The area has been identified as suitable for setting up tidal energy projects due to its favorable tidal conditions.
- The development of tidal energy in the Gulf of Kutch can contribute to India's renewable energy goals and reduce reliance on fossil fuels.
Other Options:
- Northern areas: The northern areas of India, such as the Himalayan region, do not have significant tidal movements and are not suitable for harnessing tidal energy.
- Kalpakkam in Tamil Nadu: Kalpakkam is located on the east coast of India and does not have strong tidal currents, making it less suitable for tidal energy harnessing.
- Malabar coast: The Malabar coast, located in Kerala, experiences moderate tidal movements but may not have the ideal conditions for large-scale tidal energy projects.
In conclusion, the Gulf of Kutch in Gujarat is the potential site for harnessing tidal energy in India due to its strong tidal currents, significant tidal range, and favorable conditions for tidal energy projects.

Wind Speed Requirements for Wind-Electric Generators

Wind-electric generators require a certain minimum wind speed in order to function properly. The wind speed determines the amount of power that can be generated by the turbine. The minimum wind speed required for a wind-electric generator is:

A: 1.5 km/h

- This wind speed is too low for a wind-electric generator to operate efficiently. It is not sufficient to generate significant power.

B: 150 km/h

- This wind speed is too high for most wind-electric generators to operate. It is well above the maximum operating limit for most turbines.

C: 1500 km/h

- This wind speed is extremely high and well beyond the capabilities of any wind-electric generator. It is not realistic or feasible for a turbine to operate at such high speeds.

D: 15 km/h

- This wind speed is the correct minimum requirement for a wind-electric generator to work properly. At this speed, the turbine can start turning and generate a significant amount of power.

Therefore, the correct answer is D: 15 km/h. Wind-electric generators require wind speeds of at least 15 km/h to function properly and generate power.

Cadmium rods are used as control rods as they are capable of absorbing neutrons without themselves Fissioning. Boron rods are used as control rods in nuclear  reactor to control the fission rate of uranium and plutonium.

Solar Cells: Element Used in Making
- Silicon: Silicon is the primary element used in making solar cells. It is a semiconductor material that possesses the necessary properties for converting sunlight into electricity.
- Solar cells are made up of silicon wafers, which are thin slices of silicon that are doped with impurities to create a p-n junction, forming the basic structure of a solar cell.
- The p-n junction allows for the separation of charge carriers (electrons and holes) when sunlight strikes the surface of the solar cell. This separation creates an electric field, which generates an electric current when connected to an external circuit.
- Silicon is abundant in the Earth's crust and has excellent electrical properties, making it an ideal material for solar cell production.
- Lead: Lead is not commonly used in the production of solar cells. While lead may be present in some older or less advanced solar cell technologies, modern solar cells predominantly utilize silicon as the primary material.
- Stannous: Stannous, also known as tin, is not a commonly used element in the production of solar cells. Silicon remains the primary material due to its superior electrical properties and abundance.
- Sulphur: Sulphur is not used in the production of silicon solar cells. However, it is worth noting that there are other types of solar cells, such as organic solar cells, that may incorporate sulphur compounds as part of their structure.

Atomic Number = Mass no. - No. Of neutrons
⇒ 295 - 196
⇒  99 
So, option ( a) is the correct answer.

Explanation:
The correct answer is C: Nuclear energy. Here is a detailed explanation of why this option is not ultimately derived from the Sun's energy:
- Wind energy: Wind energy is derived from the Sun's energy. The Sun's heat causes air to move, resulting in wind. Wind turbines harness the kinetic energy of the wind and convert it into electrical energy.
- Geothermal energy: Geothermal energy is derived from the heat generated by the Earth's core. While the Sun's energy does not directly heat the Earth's core, it does contribute to the overall heat budget of the planet, including the energy stored in the Earth's crust.
- Bio-mass: Biomass refers to organic matter, such as plants and trees, that can be burned to produce heat or converted into biofuels. Biomass is derived from the Sun's energy through the process of photosynthesis, where plants convert sunlight into chemical energy.
- Nuclear energy: Nuclear energy is generated through nuclear reactions, specifically nuclear fission or fusion. It is not directly derived from the Sun's energy, as nuclear reactions occur due to the release of energy from the nucleus of an atom, not from the Sun's radiation.
In summary, while wind energy, geothermal energy, and biomass are all ultimately derived from the Sun's energy, nuclear energy is not.

Ocean Thermal Energy Conversion (OTEC)
Definition:
Ocean Thermal Energy Conversion (OTEC) is a sustainable energy technology that harnesses the temperature difference between warm surface seawater and cold deep seawater to generate electricity.
Full Form:
The full form of OTEC is Ocean Thermal Energy Conversion.
Explanation:
Ocean Thermal Energy Conversion (OTEC) is a process that involves the following steps:
1. Heat Exchange: Warm surface seawater is used to heat a working fluid with a low boiling point, such as ammonia or propane.
2. Power Generation: The working fluid vaporizes and expands in a turbine, generating electricity.
3. Cold Water Condensation: Cold deep seawater is used to condense the vaporized working fluid back into a liquid state.
4. Recirculation: The condensed working fluid is recirculated back to the heat exchanger to repeat the cycle.
Advantages of OTEC:
- Renewable and Sustainable: OTEC utilizes the temperature difference between warm surface water and cold deep water, which is a constant and renewable resource.
- Clean Energy: OTEC does not produce greenhouse gas emissions or other pollutants during operation.
- Potential for Desalination: OTEC systems can also be used for desalination, providing fresh water in addition to electricity.
- Coastal Development: OTEC plants can be integrated with coastal infrastructure, reducing transmission losses and promoting local economic development.
Limitations of OTEC:
- High Initial Costs: The construction and installation of OTEC plants can be expensive.
- Distance from Shore: OTEC plants need to be located relatively close to shore to access both warm surface water and cold deep water.
- Environmental Impact: OTEC plants may have some impact on marine ecosystems, such as changes in water temperature and flow patterns.
In conclusion, Ocean Thermal Energy Conversion (OTEC) is a promising renewable energy technology that utilizes the temperature difference in ocean water to generate electricity. It offers several advantages, including sustainability, clean energy production, and the potential for desalination. However, it also faces challenges such as high initial costs and potential environmental impacts.

Statement A : Oceans serve as the most potential source of renewable energy
- This statement is true.
- Oceans have the potential to provide a significant amount of renewable energy.
- Various technologies, such as tidal energy, wave energy, and ocean thermal energy conversion, can harness the power of the ocean to generate electricity.
- Oceans cover about 71% of the Earth's surface, making them a vast resource for renewable energy.
Statement B : Energy from nuclear fusion creates more pollution than energy from nuclear fission
- This statement is false.
- Nuclear fusion is considered a cleaner and safer form of energy compared to nuclear fission.
- Nuclear fusion does not produce long-lived radioactive waste like nuclear fission.
- Fusion reactions involve the fusion of light atomic nuclei, such as hydrogen isotopes, which release a large amount of energy without emitting harmful pollutants or greenhouse gases.
Conclusion:
- Statement A is true as oceans are a potential source of renewable energy.
- Statement B is false as energy from nuclear fusion is cleaner and produces less pollution compared to energy from nuclear fission.

Present Contribution of Hydro Electric Power Stations to the Electricity Generated in India
The present contribution of hydroelectric power stations to the electricity generated in India is 23%.
Here is a detailed explanation:
1. Overview of Electricity Generation in India
- India is one of the largest electricity producers in the world.
- The country has a diverse mix of energy sources for electricity generation, including fossil fuels (coal, oil, and natural gas), renewable sources (hydroelectric power, wind energy, solar power), and nuclear power.
2. Role of Hydroelectric Power Stations
- Hydroelectric power stations play a significant role in the electricity generation in India.
- They harness the power of flowing or falling water to generate electricity.
- Hydroelectric power is considered a clean and renewable energy source.
3. Contribution of Hydroelectric Power Stations in India
- As of the present scenario, hydroelectric power stations contribute 23% of the total electricity generated in India.
- This means that nearly a quarter of the country's electricity comes from hydroelectric power.
- Hydroelectric power is the second-largest source of electricity in India after thermal power.
4. Factors Influencing Hydroelectric Power Generation
- The contribution of hydroelectric power to the overall electricity generation in India can vary depending on several factors, including:
- Availability of water resources and suitable locations for dams and reservoirs.
- Monsoon patterns and rainfall levels, as they directly impact water availability.
- Government policies and incentives to promote hydroelectric power generation.
5. Future Prospects and Potential
- India has significant untapped hydropower potential, especially in regions like the Himalayas and the Northeastern states.
- The government has set targets to increase the share of renewable energy, including hydroelectric power, in the overall electricity mix.
- With advancements in technology and infrastructure, the contribution of hydroelectric power stations to electricity generation in India is expected to increase in the coming years.
In conclusion, hydroelectric power stations currently contribute 23% of the electricity generated in India. This clean and renewable energy source plays a crucial role in the country's energy mix, and there is potential for further growth in the future.

Incorrect Statement Regarding Solar Cooker:
A: It does not require solar cells to convert solar energy into electrical energy.
- This statement is correct. Solar cookers do not require solar cells to convert solar energy into electrical energy. Solar cells are used in solar panels to generate electricity, but solar cookers use the direct heat from the sun to cook food.
B: In it, cooking takes comparatively longer time.
- This statement is correct. Solar cookers rely on the sun's energy to heat up and cook food. Compared to traditional cooking methods, solar cookers generally take longer to cook food because they rely on the natural intensity of sunlight.
C: It requires neither fuel nor attention while cooking.
- This statement is correct. Solar cookers use the sun's energy as the fuel source and do not require any additional fuel, such as gas or electricity. Once the food is placed in the solar cooker, it can be left unattended as it cooks.
D: It is made from semiconductor material.
- This statement is incorrect. Solar cookers are not made from semiconductor material. They are typically made from reflective materials, such as metal or glass, which help concentrate and trap the sun's heat for cooking purposes.
Therefore, the incorrect statement is option D: "It is made from semiconductor material."

1 amu energy = 931 MeV 
Therefore, 3/2 amu = [ 3/2 * 931] MeV
⇒ 1396.5 MeV 

To make a hydrogen bomb, one would still need uranium or plutonium as well as two other isotopes of hydrogen, called deuterium and tritium. The hydrogen bomb relies on fusion, the process of taking two separate atoms and putting them together to form a third atom. 

Why do we use black surfaces in solar devices?
There are several reasons why black surfaces are used in solar devices. Here is a detailed explanation:
1. Absorption of sunlight:
- Black surfaces have a high absorption rate for sunlight.
- They are able to absorb a larger amount of solar radiation compared to lighter surfaces.
- This is because black surfaces have a higher level of pigmentation, which allows them to absorb more photons.
2. Conversion of sunlight into heat:
- When black surfaces absorb sunlight, the energy is converted into heat.
- This heat can then be used for various purposes, such as heating water or generating electricity in solar devices.
- Black surfaces are efficient in converting sunlight into heat energy due to their high absorption rate.
3. Enhanced heat transfer:
- Black surfaces have the ability to transfer heat more effectively compared to lighter surfaces.
- This is because dark-colored materials have a higher thermal conductivity.
- The heat absorbed by black surfaces can be easily transferred to the surrounding area or to a working fluid within the solar device.
4. Minimization of reflection:
- Black surfaces minimize the reflection of sunlight.
- When light is reflected off a surface, it is not being utilized for energy conversion.
- By using black surfaces, the amount of reflected light is reduced, ensuring that more sunlight is available for energy conversion.
5. Aesthetics:
- Black surfaces are commonly used in solar devices for aesthetic purposes.
- The dark color gives a sleek and modern look to the devices, making them visually appealing.
In conclusion, black surfaces are used in solar devices because they have a high absorption rate for sunlight, efficiently convert sunlight into heat, enhance heat transfer, minimize reflection, and provide an aesthetically pleasing appearance.

Statement A: Oceans serve as the most potential source of renewable energy
Statement B: Energy from nuclear fusion creates more pollution than energy from nuclear fission
Answer: B. Statement A is true, B is false
Explanation:
Statement A: Oceans serve as the most potential source of renewable energy
- Oceans have the potential to provide various forms of renewable energy, such as wave energy, tidal energy, and ocean thermal energy conversion.
- These energy sources are abundant, sustainable, and do not produce greenhouse gas emissions.
- Therefore, statement A is true.
Statement B: Energy from nuclear fusion creates more pollution than energy from nuclear fission
- Nuclear fusion is a process that releases energy by combining atomic nuclei, while nuclear fission is a process that releases energy by splitting atomic nuclei.
- Both processes have the potential to generate significant amounts of energy without greenhouse gas emissions.
- However, nuclear fusion has the advantage of producing less radioactive waste compared to nuclear fission.
- Therefore, statement B is false.
In conclusion, statement A is true as oceans serve as a potential source of renewable energy, while statement B is false as energy from nuclear fusion does not create more pollution than energy from nuclear fission.

Energy Sources Not Derived from the Sun:
There are several sources of energy that are not derived from the sun. These include:
1. Ocean wave energy: Ocean waves are generated by the wind, which is ultimately powered by the sun. However, wave energy itself is not directly derived from the sun.
2. Biomass energy: Biomass refers to organic materials such as wood, agricultural crops, and waste. These materials can be burned or converted into biogas to produce energy. While the sun is necessary for the growth of biomass, the energy is not directly derived from the sun.
3. Nuclear energy: Nuclear energy is generated through nuclear reactions, specifically nuclear fission or fusion. It does not rely on sunlight or solar radiation for its generation.
4. Wind energy: Wind is a result of uneven heating of the Earth's surface by the sun. However, wind energy is not derived directly from the sun but rather from the kinetic energy of moving air masses.
Out of these options, the energy source that is not derived from the sun is nuclear energy (option C). Nuclear energy is generated through the process of nuclear reactions, which involve the splitting or fusion of atomic nuclei. This process does not rely on sunlight or solar radiation for its generation.

The solar panel is made by combining a large number of solar cells:
- Solar cells: These are the basic building blocks of a solar panel. They are made of semiconductor materials, such as silicon, which can convert sunlight into electricity through the photovoltaic effect.
- Combining: Multiple solar cells are connected together in series or parallel to form a solar panel. This allows them to generate a higher voltage or current, depending on the desired application.
- Large number: Solar panels typically consist of many solar cells. The number of cells used depends on the desired power output and size of the panel. More cells result in higher power output.
- Series connection: Solar cells can be connected in series, where the positive terminal of one cell is connected to the negative terminal of the next cell. This increases the voltage output of the panel.
- Parallel connection: Solar cells can also be connected in parallel, where the positive terminals are connected together and the negative terminals are connected together. This increases the current output of the panel.
- Encapsulation: Once the solar cells are connected, they are encapsulated in a protective material, such as tempered glass, to protect them from environmental factors like moisture and physical damage.
- Backsheet and frame: The encapsulated solar cells are then attached to a backsheet, which provides further protection and insulation. The panel is also mounted on a frame to provide structural support.
- Junction box: A junction box is attached to the back of the solar panel, which houses the electrical connections. This allows the solar panel to be easily connected to other panels or an electrical system.
- Wiring: Electrical wires are used to connect the solar cells in series or parallel and to connect the solar panel to the junction box.
- Final testing: Once the solar panel is assembled, it undergoes testing to ensure it is functioning properly and generating the expected amount of electricity.
In conclusion, a solar panel is made by combining a large number of solar cells, which are connected together in series or parallel. These cells are encapsulated, attached to a backsheet and frame, and connected to a junction box. The final product is tested for functionality before being used to generate solar power.

Importance of carefully choosing the site of a hydroelectric plant:

There are several factors that should be taken into consideration when choosing the site for a hydroelectric plant:

Affects the organisms of the region:
- The site selection should consider the impact on the local ecosystem and biodiversity.
- Construction of the plant may require the flooding of large areas, which can displace or harm local wildlife.
- The alteration of river flow can also disrupt fish migration patterns and affect aquatic organisms.
Produces a large amount of electricity:
- The site should have a sufficient and reliable water source to ensure a continuous supply of water to the plant.
- It should also have a significant water flow or head (height difference) to generate a substantial amount of electricity.
Is expensive:
- The cost of constructing a hydroelectric plant can be high, especially if extensive infrastructure is required.
- Factors such as land acquisition, environmental impact assessments, and transmission infrastructure should be considered.
Produces a large amount of CO and CO2:
- Hydroelectric power is considered a clean energy source as it does not directly produce CO2 emissions during operation.
- However, the construction process may involve emissions due to the use of heavy machinery and transportation.
In conclusion, the site selection for a hydroelectric plant should carefully balance the environmental impact, electricity generation potential, cost considerations, and emissions during construction. It is crucial to conduct thorough assessments and studies to ensure the chosen site is the most suitable option.

Biogas is produced from organic waste which biodegrades by means of bacteria in an anaerobic environment through a process of Anaerobic Digestion. It uses anaerobic digestion to recycle the organic materials (plant and animal products), turning them into biogas, which contains both energy (gas), and valuable soil products (liquids and solids). Anaerobic digestion is a series of biological processes in which microorganisms break down biodegradable material in the absence of oxygen. Hence the correct answer would be (A).

Types of Radiations emitted by a 100W Electric Lamp:
The 100W electric lamp emits various types of radiations in addition to visible light. These include:
Infrared Radiation:
- Infrared radiation is a type of electromagnetic radiation with longer wavelengths than visible light.
- It is emitted by objects that have heat. When the lamp is glowing, it produces heat, and therefore, it emits infrared radiation.
- Infrared radiation is commonly used for heating purposes and in devices such as remote controls.
Ultraviolet Radiation:
- Ultraviolet radiation is a type of electromagnetic radiation with shorter wavelengths than visible light.
- Some of the energy from the electric lamp is converted into ultraviolet radiation.
- Ultraviolet radiation is not visible to the human eye but can have harmful effects on the skin and eyes if exposed for an extended period.
X-rays:
- X-rays are a type of high-energy electromagnetic radiation.
- Although a 100W electric lamp does not emit a significant amount of X-rays, there may be a minimal emission due to the high energy and temperature involved.
- X-rays are commonly used in medical imaging, such as X-ray scans and radiography.
Gamma Radiation:
- Gamma radiation is the most energetic form of electromagnetic radiation.
- It is not emitted by a 100W electric lamp. Gamma radiation is typically associated with radioactive materials and nuclear reactions.
Therefore, in addition to visible light, a 100W electric lamp primarily emits infrared radiation and may emit a minimal amount of ultraviolet radiation and X-rays. It does not emit gamma radiation.

Geothermal energy is feasible in regions that:
- Are over hot spots in the crust: Geothermal energy is harnessed from the heat generated by the Earth's core. Hot spots in the crust, such as areas near volcanoes or areas with significant tectonic activity, have higher geothermal energy potential.
- Have thermal: Geothermal energy is derived from the heat stored within the Earth. Regions that have thermal energy reservoirs, such as areas with high temperatures underground, are suitable for geothermal energy production.
- Are near the sea: Coastal areas have the potential to utilize geothermal energy through the process of ocean thermal energy conversion (OTEC). This technology harnesses the temperature difference between warm surface waters and cold deep waters to generate electricity.
- Do not have coal mines: The presence of coal mines is not a requirement for geothermal energy feasibility. Geothermal energy relies on the Earth's natural heat, whereas coal mining is related to the extraction of fossil fuel for energy production.
Overall, geothermal energy is most feasible in regions that have hot spots in the crust, thermal energy reservoirs, and proximity to the sea. These factors contribute to a higher potential for geothermal energy generation and utilization.

A hydrogen bomb is based on nuclear fusion reactions. So, a light element P of mass number 2 is the most suitable to make it.