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
391
Closing (decommissioning) a nuclear power plant can cost more than building it.
Answer:
True
Decommissioning involves decades of dismantling, decontamination, spent fuel management, and long-term waste handling. Regulatory and safety requirements drive high costs. Life-cycle planning must budget for this end-of-life phase.
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392
A fast-growing city asks how to improve air quality first. The most effective initial step is to:
Answer:
Improve transportation (car-pool lanes, buses, light rail)
Urban transport is a major source of NOx, PM, and ozone precursors. Modal shifts and reduced vehicle-kilometers cut emissions quickly. Other options have minimal immediate urban air-quality impact.
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393
Acid deposition (acid rain):
Answer:
Often crosses national boundaries, causing disputes
SOâ‚‚/NOx emissions can travel long distances before depositing, making it a transboundary issue. It acidifies soils and waters, damaging biota and infrastructure. Ozone depletion is stratospheric chemistry, not caused by acid rain.
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394
A septic tank is:
Answer:
septic tank is:
Septic tanks settle solids and promote anaerobic digestion in quiescent conditions. There is no fixed media, so biomass remains suspended/settled. Effluent typically requires soil-based polishing.
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395
Automobile air pollution is best reduced by fitting:
Answer:
Catalytic converter
Catalytic converters oxidize CO and hydrocarbons and reduce NOx to less harmful gases. They are standard on modern vehicles. Other devices are for stationary sources.
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396
Which device removes the finest particulate matter most effectively?
Answer:
Electrostatic precipitator
ESPs charge fine particles and collect them on plates with high efficiency, especially for sub-micron dust. Cyclones are for coarse particles. Baghouses are also excellent but can be limited by temperature/chemistry.
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397
Best device for removing gaseous air pollutants from exhaust streams:
Answer:
Wet scrubber
Wet scrubbers absorb or chemically neutralize gases using liquids. ESPs and baghouses target particulates; cyclones remove coarse dust. Gas control often needs absorption/adsorption or catalytic systems.
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398
Which is an example of ex-situ conservation?
Answer:
Seed banks
Seed banks store germplasm outside natural habitats. National parks, sanctuaries, and sacred groves protect species in situ. Ex-situ complements in-situ for comprehensive conservation.
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399
The least porous soil among the following is:
Answer:
Clayey soil
Clay particles are tiny and pack tightly, leaving minimal macropores for air and water movement. Loam balances pore sizes; peat is highly porous; silt is intermediate. Low porosity affects aeration and drainage.
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400
Which is NOT used for ex-situ plant conservation?
Answer:
Shifting cultivation
Ex-situ methods conserve genetic resources outside natural habitats. Shifting cultivation is a land-use practice, not a conservation tool. Seed and field gene banks and botanical gardens are standard ex-situ strategies.
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