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
261
The greenhouse effect is mainly caused by:
Answer:
Increase in CO₂
Elevated CO₂ and other GHGs trap outgoing infrared radiation, warming the lower atmosphere. Oxygen variations are not the mechanism. Anthropogenic emissions are the primary driver.
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262
Soil pollution can be caused by:
Answer:
an be caused by:
Acid deposition acidifies soils, mobilizes toxic metals, and disrupts nutrients. Aerosols and ozone are primarily air pollutants; PAN harms vegetation but “soil pollution” is most directly tied here to acid rain’s deposition effects.
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263
Noise pollution is measured in:
Answer:
Decibel
The decibel (dB) quantifies sound intensity on a logarithmic scale. Hertz measures frequency, candela measures luminous intensity, and Dobson units measure ozone column density.
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264
Phytoplankton are:
Answer:
re:
Phytoplankton are microscopic photosynthetic organisms in aquatic systems. They form the base of aquatic food chains. Zooplankton and fish depend on their productivity.
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265
Photosynthesis is found in:
Answer:
Producers
Producers (plants, algae, cyanobacteria) capture light energy to synthesize organic compounds. Consumers and decomposers depend on this primary production. Photosynthesis underpins most food webs.
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266
Nitrogen gas returns to the atmosphere chiefly by the action of:
Answer:
Denitrifying bacteria
Denitrifiers convert nitrates to gaseous N₂ (and N₂O), closing the nitrogen cycle. Nitrogen fixers do the opposite—convert N₂ to ammonia. Nitrifiers oxidize ammonia to nitrite/nitrate.
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267
The term “Ecology” was coined by:
Answer:
Ernst Haeckel
Haeckel introduced “Ökologie” in 1866 to describe the study of organisms in relation to their environment. Tansley later formalized the concept of the “ecosystem.” Aristotle and Linnaeus made other foundational contributions.
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268
The famous Minamata disease in Japan was due to accumulation of ______ in fish:
Answer:
Mercury
Industrial discharge led to methylmercury bioaccumulation in seafood, causing neurological damage in residents. The tragedy highlighted biomagnification risks. It led to stricter pollution controls.
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269
The 3R principle in waste management stands for:
Answer:
Reduce, Reuse, Recycle
The 3Rs prioritize cutting waste creation, then reusing items, and finally recycling materials. This hierarchy reduces resource extraction and landfill use. It’s central to circular economy strategies.
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270
The word “Tsunami” is derived from two Japanese words meaning:
Answer:
Tsu (harbour) and nami (wave)
“Tsunami” literally means “harbour wave,” reflecting their destructive amplification in harbours. They are long-wavelength sea waves generated by undersea disturbances. The term does not mean “big flow.”
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