General Science/Everyday Science MCQs
Topic Notes: General Science/Everyday Science
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
291
Noise pollution can be minimized by:
Answer:
Reducing noise at the source
Source control (quieter engines, mufflers, isolation mounts) is the most effective measure. Barriers, zoning, and personal protection add layers of defense. Urbanization by itself does not reduce noise and may increase it.
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292
A major source of fly ash is:
Answer:
Thermal power plants
Coal-fired power stations generate large quantities of fly ash carried with flue gases. Proper electrostatic precipitators and ash handling reduce emissions. Fly ash can be reused in cement and bricks.
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293
Mining practices often lead to:
Answer:
Loss of grazing and fertile land
Mining removes topsoil, fragments landscapes, and can contaminate soils and waterways. While mining may indirectly attract workers (population changes), the direct environmental impact is land degradation. Rehabilitation is essential but challenging.
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294
Which of the following are **biodegradable** pollutants?
Answer:
Domestic sewage
Domestic sewage contains organic matter that microorganisms can degrade. Many plastics persist for decades; some detergents are biodegradable, but not all. The most clearly biodegradable among these options is sewage.
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295
A natural source of air pollution among the following is:
Answer:
natural source of air pollution among the following is:
Volcanoes emit ash and gases (SO₂, CO₂), directly polluting the air. Solar flares are space weather events, not terrestrial air pollutants, and earthquakes don’t emit atmospheric pollutants per se. Thus, volcanism is the correct natural source.
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296
Environmental pollution is largely due to:
Answer:
ue to:
Rapid urbanization increases waste, traffic, and emissions; deforestation reduces carbon sinks and increases erosion. Afforestation generally mitigates pollution and improves ecosystems. Thus both (a) and (b) contribute.
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297
Molasses from the sugar industry is used to produce:
Answer:
Bioethanol
Fermentation of molasses (a sugar-rich by-product) yields ethanol, used as transport fuel or blended with petrol. Biodiesel comes from oils/fats via transesterification, not molasses. Hydrogen production typically requires different processes.
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298
Biogas is mainly composed of:
Answer:
Methane and carbon dioxide
Typical biogas contains ~55–70% methane and ~30–45% CO₂, with traces of H₂S and moisture. Methane provides the energy content. Cleaning (scrubbing) can upgrade biogas to biomethane.
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299
The primary source of electromagnetic radiation for Earth is the:
Answer:
Sun
The Sun emits a broad spectrum of EM radiation (UV, visible, IR) that powers climate and photosynthesis. Tides and wind are energy flows driven indirectly by solar and lunar forces. Water is a medium, not a radiation source.
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300
Cow dung can be used:
Answer:
All of the above
Dried dung is a traditional fuel, while anaerobic digestion produces methane-rich biogas for cooking or power. The digested slurry remains a valuable fertilizer. This circular use reduces waste and emissions.
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