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
511
Which of the following best describes chlorofluorocarbons (CFCs)?
Answer:
All of the above
CFCs were once considered safe chemicals, used in refrigeration and sprays. Their stability allows them to reach the stratosphere intact. There they cause ozone destruction.
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512
Ozone thickness is measured in:
Answer:
Dobson units
The Dobson Unit is a standard measure of ozone column density. One DU equals a layer of pure ozone 0.01 mm thick at standard temperature and pressure. It is used globally by scientists.
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513
The normal average thickness of the stratospheric ozone layer is about:
Answer:
300 DU
Ozone is measured in Dobson Units (DU). A global average of ~300 DU provides UV protection. Seasonal and regional variations occur, especially over Antarctica.
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514
The major compound responsible for destruction of stratospheric ozone is:
Answer:
CFCs
Chlorofluorocarbons release chlorine atoms in the stratosphere. One chlorine atom can destroy thousands of ozone molecules. This is the main cause of the ozone hole.
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515
Which of the following statements about ozone is true?
Answer:
All of the above
Ozone acts as both a pollutant and protector. At ground level, it causes smog and breathing issues. In the stratosphere, it shields life from UV rays.
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516
The ozone layer is found in which atmospheric region?
Answer:
Stratosphere
The ozone layer lies 15–35 km above Earth in the stratosphere. It absorbs harmful ultraviolet (UV) radiation. This protects living organisms from DNA damage.
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517
The process where acid rain removes nutrients from soil is called:
Answer:
Leaching
Leaching occurs when rainwater dissolves and washes away soil nutrients. Acidic conditions accelerate this process. This depletes fertility and affects plant growth.
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518
Which of the following is an effect of acid rain?
Answer:
n effect of acid rain?
Acid rain leaches nutrients from soil, lowering fertility. It also acidifies lakes, harming aquatic life. Indirectly, it damages crops and forests.
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519
The reduction in brightness of the Taj Mahal is mainly due to:
Answer:
Air pollution
Sulphur dioxide and particulate matter from nearby industries discolor the marble. This phenomenon is called “marble cancer.” Acid rain further erodes its surface.
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520
Atmospheric oxidation of SO₂ and SO₃ is influenced by:
Answer:
All of the above
The conversion of sulfur oxides to sulfates is promoted by sunlight, moisture, and reactive gases. Hydrocarbons enhance oxidation reactions. This leads to acid rain formation.
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