Test: Sources of Energy- 3 - UPSC MCQ

Wood is used as a fuel and can be renewed by planting more trees. Whereas, all other options are obtained from fossils and hence, are non-renewable.

The simple reason of covering the glass plates with solar cookers because the sunlight can pass through the glass easily and it gets absorbed inside the cooker. The more it traps the heat rays , thus it is helpful for heating the food.

Wind Speed Requirements for Wind-Electric Generators:
To work properly, wind-electric generators require a certain minimum wind speed. Let's explore the options given and determine which one is correct.
A: 1.5 km/h
- This wind speed is too low for wind-electric generators to function properly. It is not sufficient to generate significant power.
B: 15 km/h
- This wind speed is the correct answer. Wind-electric generators typically require a wind speed of at least 15 km/h to start generating power. It is the minimum threshold for efficient operation.
C: 150 km/h
- This wind speed is too high for wind-electric generators. While they can withstand strong winds, 150 km/h is beyond their operational limit and may cause damage.
D: 1500 km/h
- This wind speed is extremely high and far beyond the capability of wind-electric generators. Such wind speeds are typically associated with severe storms and hurricanes.
Therefore, the correct answer is B: 15 km/h. Wind-electric generators need wind speeds of at least 15 km/h to work properly.

Hydropower facilities can have large environmental impacts by changing the environment and affecting land use, homes, and natural habitats in the dam area. Most hydroelectric power plants have a dam and a reservoir.

The generation of electricity from the ocean is possible by harnessing the energy present in waves. This energy can be utilized to produce electricity through various methods such as wave energy converters. Additionally, the ocean also contains stored thermal energy, which can be tapped into to generate electricity using technologies like ocean thermal energy conversion (OTEC).
Here is a detailed explanation of the options:
A: Kinetic energy of the waves but not stored thermal energy
- Waves possess kinetic energy due to the motion of water particles. This energy can be harnessed using wave energy converters to generate electricity.
- However, this option states that stored thermal energy cannot be utilized, which is incorrect.
B: Stored thermal energy but not kinetic energy of the waves
- This option states that only stored thermal energy can be used to generate electricity from the ocean, neglecting the kinetic energy of the waves.
- Waves have significant kinetic energy that can be converted into electricity, making this option incorrect.
C: Kinetic energy of the waves as well as stored thermal energy
- This option correctly states that both kinetic energy of the waves and stored thermal energy can be utilized for electricity generation.
- Wave energy converters can harness the kinetic energy of waves, while OTEC systems can extract heat from the ocean's thermal gradient to generate power.
D: Neither kinetic energy of the waves nor stored thermal energy
- This option states that both kinetic energy of the waves and stored thermal energy cannot be used for electricity generation, which is incorrect.
Therefore, the correct answer is option C: Kinetic energy of the waves as well as stored thermal energy.

Which energy is not derived from the sun?
There are various sources of energy that are not derived from the sun. The energy sources include:
Nuclear energy:
- Nuclear energy is generated through the process of nuclear fission or fusion.
- It involves the splitting or combining of atomic nuclei to release a large amount of energy.
- This energy is not directly derived from the sun.
Wind energy:
- Wind energy is harnessed by converting the kinetic energy of wind into electrical energy.
- Wind turbines capture the wind's energy and convert it into electricity.
- Although wind is indirectly influenced by the sun's radiation, wind energy does not directly come from the sun.
Biomass energy:
- Biomass energy is derived from organic materials, such as plants and animal waste.
- These organic materials can be burned or converted into biogas to produce heat or electricity.
- Biomass energy is not directly dependent on the sun.
Ocean-wave energy:
- Ocean-wave energy is obtained from the motion of ocean waves.
- Wave energy converters capture the energy from the waves and convert it into electricity.
- While waves are generated by wind, ocean-wave energy does not directly come from the sun.
Therefore, the correct answer to the question is A: Nuclear energy. Nuclear energy is not derived from the sun.

Geothermal energy is feasible in regions that:
1. Are over hot spots in the crust:
- Geothermal energy is generated by harnessing the heat from the Earth's crust, particularly in areas where there are hot spots.
- These hot spots are locations where molten magma is close to the surface, causing the surrounding rocks to heat up.
2. Have a high geothermal gradient:
- The geothermal gradient refers to the rate at which the temperature increases with depth in the Earth's crust.
- Regions with a high geothermal gradient are more suitable for geothermal energy production as they indicate a significant amount of heat available.
3. Have suitable geological conditions:
- The presence of permeable rocks or fractures in the Earth's crust is essential for the extraction of geothermal energy.
- These geological conditions allow for the circulation of water or other fluids through the hot rocks, which can be used to generate electricity or provide heating.
4. Are relatively close to the Earth's surface:
- Geothermal energy is easier to extract in regions where the hot rocks are closer to the surface.
- In such areas, drilling deep wells is not required, making the extraction process more cost-effective.
5. Have appropriate water resources:
- Geothermal power plants require a significant amount of water for the extraction and conversion of geothermal energy.
- Therefore, regions with ample water resources, such as underground reservoirs or nearby lakes and rivers, are beneficial for geothermal energy production.
6. Have supportive government policies:
- The feasibility of geothermal energy also depends on the presence of supportive government policies and regulations.
- Governments that incentivize and promote the development of geothermal energy can make it more financially viable and attractive for investors.
In conclusion, geothermal energy is feasible in regions that are over hot spots in the crust, have a high geothermal gradient, suitable geological conditions, are relatively close to the Earth's surface, have appropriate water resources, and supportive government policies.

Explanation:
The correct answer is option C: nuclear energy. Here's why:
1. Wood: Wood is a widely used biomass energy source. It is derived from trees and can be burned to produce heat or converted into biofuels.
2. Gobar-gas: Gobar-gas, also known as biogas, is another example of a biomass energy source. It is produced by the anaerobic digestion of organic materials such as animal manure, crop residues, and food waste.
3. Nuclear energy: Nuclear energy is not considered a biomass energy source. It is obtained from the nucleus of an atom through processes such as nuclear fission or fusion. Unlike biomass energy sources, nuclear energy does not rely on organic materials.
4. Coal: Coal is a fossil fuel and not a biomass energy source. It is formed from the remains of plants and trees that lived millions of years ago. While coal is derived from organic matter, it undergoes geological processes that distinguish it from biomass energy sources.
In summary, while wood, gobar-gas, and coal are examples of biomass energy sources, nuclear energy is not.

Explanation:
The correct answer is C: nuclear energy. Here is a detailed explanation of why nuclear energy is not ultimately derived from the Sun's energy:
1. Geothermal energy:
- Geothermal energy is generated from the heat stored within the Earth's core.
- This heat is a result of the radioactive decay of elements such as uranium and thorium.
- These radioactive elements were formed during the formation of the Earth, billions of years ago.
- Therefore, geothermal energy indirectly originates from the Sun's energy as it is a byproduct of the Earth's formation and ongoing radioactive decay.
2. Wind energy:
- Wind energy is created by the movement of air masses, which is primarily driven by the uneven heating of the Earth's surface by the Sun.
- The Sun's energy heats the Earth's surface unevenly, causing differences in air pressure.
- These pressure differences create winds as air moves from areas of high pressure to areas of low pressure.
- Thus, wind energy is a direct result of the Sun's energy.
3. Bio-mass:
- Bio-mass refers to organic matter derived from plants and animals.
- Plants use photosynthesis to convert sunlight into chemical energy, which is stored in their tissues.
- This stored energy is then transferred to other organisms through the food chain.
- When bio-mass is burned or decomposed, the stored energy is released in the form of heat or electricity.
- Therefore, bio-mass energy is ultimately derived from the Sun's energy.
4. Nuclear energy:
- Nuclear energy is generated by the process of nuclear fission or fusion.
- Nuclear fission involves splitting the nucleus of an atom, usually uranium or plutonium, which releases a large amount of energy.
- Nuclear fusion involves combining the nuclei of atoms, such as in the Sun's core, which also releases a significant amount of energy.
- However, the nuclear reactions that produce energy in nuclear power plants are not directly dependent on the Sun's energy.
- Nuclear fuel, such as uranium, is a non-renewable resource that was formed through various natural processes on Earth.
- Therefore, nuclear energy is not ultimately derived from the Sun's energy.
In summary, while most sources of energy, such as geothermal, wind, and bio-mass, are ultimately derived from the Sun's energy, nuclear energy is not. Nuclear energy is generated through nuclear fission or fusion processes that are independent of the Sun's energy.

Biomass is another semi - conventional energy source because it is in the process of becoming mainstream. Biomass energy comes from plant material. Biomass can be used for heating and generating electricity. 
Nuclear energy is one of the most environmental friendly conventional  sources of energy as it produces fewer greenhouse gas emissions during the production of electricity.

Number of Neutrons Released in the Fission of U-235
To determine the number of neutrons released in the fission of U-235, we need to understand the process of nuclear fission and the specific properties of U-235.
1. Nuclear Fission:
Nuclear fission is a process in which the nucleus of an atom is split into two or more smaller nuclei. This process releases a large amount of energy and additional neutrons.
2. U-235:
Uranium-235 (U-235) is a specific isotope of uranium that is commonly used as fuel in nuclear reactors. U-235 is fissile, meaning it can undergo nuclear fission when bombarded with low-energy neutrons.
3. Neutron Induced Fission of U-235:
When U-235 absorbs a low-energy neutron, it becomes unstable and splits into two smaller nuclei, releasing a large amount of energy and additional neutrons. These released neutrons can then go on to induce fission in other U-235 nuclei, creating a chain reaction.
4. Neutron Multiplication Factor (k):
The number of neutrons released in each fission event plays a crucial role in sustaining a chain reaction. The neutron multiplication factor, denoted as "k," represents the average number of neutrons produced in each fission event that go on to cause subsequent fissions.
5. Average Number of Neutrons Released in U-235 Fission:
The average number of neutrons released in the fission of U-235 is approximately 2.5. This means that, on average, each fission event of U-235 produces 2.5 neutrons that can induce fission in other U-235 nuclei.
6. Answer:
Based on the information provided, the correct answer is D: 3.0.

Explanation:
An alpha particle is a type of ionizing radiation that consists of two protons and two neutrons, making it identical to the nucleus of a helium atom. It is commonly represented as ⁴He²⁺, indicating its atomic mass of 4 and its electric charge of +2.
Key Points:
- An alpha particle is a high-energy particle emitted during certain types of radioactive decay.
- It consists of two protons and two neutrons, which gives it a mass of 4 atomic mass units.
- The presence of two protons means that it carries a charge of +2.
- The combination of two protons and two neutrons makes the alpha particle identical to the nucleus of a helium atom.
- The symbol for an alpha particle is α.
- Alpha particles have relatively low penetration power and can be stopped by a sheet of paper or a few centimeters of air.
- They are commonly emitted by radioactive elements such as uranium and radium.
Therefore, the correct answer is A: Helium nucleus.