Towards Green Energy
Short Questions
1. How does a changing magnetic field induce current in a conductor?
Answer : A changing magnetic field induces a potential difference, causing current to flow.
2. Why is a turbine essential in most power plants?
Answer : It converts energy from a source into rotational energy to drive the generator.
3. What energy transformation occurs in a thermal power plant’s boiler?
Answer : Chemical energy in coal transforms into thermal energy to produce steam.
4. Why is the condenser critical in thermal power plants?
Answer : It recycles steam into water, maintaining the plant’s water cycle efficiency.
5. What gas contributes to acid rain in coal-based power plants?
Answer : Nitrogen dioxide from coal combustion leads to acid rain formation.
6. How is a chain reaction sustained in nuclear power plants?
Answer : Neutrons from uranium fission trigger further fission, sustaining the reaction.
7. Why is nuclear waste disposal a global challenge?
Answer : Radioactive waste emits harmful radiation, requiring safe, long-term storage.
8. What makes natural gas power plants more efficient than coal plants?
Answer : Higher combustion efficiency and fewer energy losses improve their performance.
9. Why don’t natural gas plants emit sulphur oxides?
Answer : Natural gas lacks sulphur, preventing sulphur oxide formation during combustion.
10. How is potential energy converted in hydroelectric plants?
Answer : Water’s potential energy becomes kinetic energy, driving the turbine.
11. Why is hydroelectric power debated as eco-friendly?
Answer : Dams cause ecosystem disruption and community displacement, raising concerns.
12. What role does a gearbox play in wind turbines?
Answer : It increases blade rotation speed to drive the generator efficiently.
13. Why is wind energy generation location-specific?
Answer : It requires high wind velocities, typically found in coastal or open areas.
14. What is the photovoltaic effect in solar cells?
Answer : Sunlight excites electrons in semiconductors, generating direct current electricity.
15. Why is an inverter needed in solar photovoltaic systems?
Answer : It converts DC electricity from solar cells to AC for household use.
16. How do solar thermal plants differ in energy conversion from photovoltaic cells?
Answer : They convert solar energy to thermal energy, then to electricity via turbines.
17. Why are fossil fuels considered non-green energy sources?
Answer : Their combustion causes pollution and depletes finite resources.
18. What limits the lifespan of coal reserves globally?
Answer : Current consumption rates predict depletion in about 200 years.
19. Why is green energy critical for sustainable development?
Answer : It reduces environmental degradation and relies on renewable resources.
20. How do solar panels achieve desired voltage and current?
Answer : Cells are connected in series for voltage and parallel for current.
Long Questions
1. How does electromagnetic induction generate electricity in power plants?
Answer : A changing magnetic field, created by a rotating magnet or moving conductor, induces a potential difference. This potential difference drives an electric current through a conductor in the generator. Turbines rotate the magnet, enabling continuous electricity production.
2. What is the process of electricity generation in a thermal power plant?
Answer : Coal is burned in a boiler to produce high-pressure steam from water. The steam drives a turbine connected to a generator, producing electricity. The steam is condensed back to water and recycled to the boiler.
3. Why do thermal power plants contribute to environmental degradation?
Answer : Burning coal emits carbon dioxide, sulphur oxide, and nitrogen oxide, causing air pollution. Soot particles harm respiratory health and contribute to asthma. These emissions also lead to global warming and acid rain.
4. How is electricity generated in a nuclear power plant?
Answer : Nuclear fission of uranium or plutonium releases thermal energy to produce steam. The steam drives a turbine, which powers a generator to produce electricity. The steam is condensed and recycled for continuous operation.
5. What are the risks associated with nuclear power generation?
Answer : Radioactive nuclear waste requires safe disposal due to harmful radiation. Accidents can release dangerous radiation, posing severe risks. Controlled fission is essential to prevent catastrophic chain reactions.
6. How does a natural gas power plant generate electricity?
Answer : Natural gas combusts with pressurized air to produce high-pressure gas. This gas drives a turbine connected to a generator, producing electricity. The process is efficient with fewer emissions than coal plants.
7. Why is natural gas power generation less polluting than coal-based plants?
Answer : Natural gas lacks sulphur, reducing sulphur oxide emissions during combustion. It produces less carbon dioxide, lowering its global warming impact. Higher efficiency means less fuel is needed for energy output.
8. What is the mechanism of electricity generation in a hydroelectric power plant?
Answer : Water from a dam’s reservoir flows downward, converting potential energy to kinetic energy. This kinetic energy rotates a turbine, driving a generator to produce electricity. The process is clean, relying on renewable water sources.
9. What environmental issues arise from hydroelectric power plants?
Answer : Dams submerge villages and forests, displacing communities and disrupting ecosystems. Blocked river flow affects aquatic life and biodiversity. These impacts question the eco-friendliness of hydroelectric power.
10. How do wind turbines convert wind energy into electricity?
Answer : Wind rotates turbine blades, transferring kinetic energy to a shaft via a gearbox. The gearbox increases rotation speed to drive a generator, producing electricity. This renewable process generates no emissions.
11. What are the challenges of using wind energy for electricity generation?
Answer : Wind turbines require high wind velocities, limiting suitable locations. Inconsistent wind speeds affect reliable power generation. High installation costs and potential impacts on wildlife are additional concerns.
12. How do solar photovoltaic cells produce electricity from sunlight?
Answer : Solar cells, made of silicon, convert sunlight into DC electricity via the photovoltaic effect. Cells are connected in series or parallel to achieve desired voltage and current. An inverter converts DC to AC for practical use.
13. What distinguishes solar thermal power plants from solar photovoltaic systems?
Answer : Solar thermal plants use sunlight to generate heat, producing steam to drive turbines. Photovoltaic systems directly convert sunlight into electricity using semiconductor cells. Thermal plants involve more energy conversions, while photovoltaic systems are simpler.
14. Why are renewable energy sources considered green energy?
Answer : Renewable sources like solar, wind, and hydroelectric are inexhaustible and sustainable. They generate electricity without polluting emissions or depleting resources. This minimizes environmental harm compared to fossil fuels.
15. Why is energy conservation critical in the context of fossil fuel usage?
Answer : Fossil fuels are finite and their combustion causes air pollution and global warming. Conserving energy reduces reliance on these depleting resources. It promotes sustainable use of renewable energy
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