These Composition and Structure of Atmosphere Important Questions cover important NCERT concepts related to atmosphere, atmospheric composition, gases, ozone layer, water vapour, atmospheric layers and weather elements.
The chapter-wise questions include MCQs, one-word questions, assertion and reason questions and analytical descriptive questions useful for UPSC, SSC, Railways, State PSC, CUET, CBSE board exams and competitive examinations.
NCERT Page Coverage: Page 64–66
These MCQs from Composition and Structure of Atmosphere help students revise important concepts related to atmospheric composition, atmospheric layers and weather-related processes.
The atmosphere is mainly composed of:
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Approximately 99 per cent of atmospheric mass is confined within:
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Which gas is essential for respiration in humans and animals?
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Carbon dioxide is important because it:
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Which gas is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation?
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The increase in atmospheric carbon dioxide is mainly due to:
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The ozone layer is mainly located between:
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The ozone layer protects Earth from:
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Water vapour in the atmosphere mainly acts like a:
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Water vapour decreases from:
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Dust particles in the atmosphere act as:
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Which atmospheric layer contains most weather phenomena?
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The average height of troposphere is about:
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The thickness of troposphere is greatest near:
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Temperature in troposphere decreases at the rate of:
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The boundary between troposphere and stratosphere is called:
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Which atmospheric layer contains ozone layer?
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The mesosphere extends up to about:
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The ionosphere contains electrically charged particles called:
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Radio waves are reflected back to Earth by:
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The uppermost atmospheric layer is:
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Which layer is most important for biological activity?
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Dust particles are highly concentrated in:
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The temperature at mesopause reaches approximately:
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The atmosphere gradually merges with outer space in:
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Which atmospheric component is highly variable?
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Which atmospheric layer is directly responsible for weather and climate changes?
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Convectional currents are strongest near:
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Which gas quantity becomes negligible at about 120 km height?
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Which among the following is NOT an element of weather and climate?
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| Question | Answer | Page Reference |
|---|---|---|
| What surrounds Earth as a gaseous envelope? | Atmosphere | Page 64 |
| Which gas is essential for respiration? | Oxygen | Page 64 |
| Which gas causes greenhouse effect? | Carbon dioxide | Page 64 |
| Which layer absorbs ultraviolet rays? | Ozone layer | Page 64 |
| Between which heights is ozone mainly found? | 10–50 km | Page 64 |
| Which atmospheric component acts like a blanket? | Water vapour | Page 64 |
| What do dust particles act as for cloud formation? | Hygroscopic nuclei | Page 65 |
| Which is the lowermost atmospheric layer? | Troposphere | Page 65 |
| What is the average height of troposphere? | 13 km | Page 65 |
| Which boundary separates troposphere and stratosphere? | Tropopause | Page 65 |
| Which atmospheric layer contains ozone layer? | Stratosphere | Page 65 |
| Which layer lies above stratosphere? | Mesosphere | Page 65 |
| What is the upper boundary of mesosphere called? | Mesopause | Page 65 |
| Which layer reflects radio waves? | Ionosphere | Page 65 |
| Which particles are found in ionosphere? | Ions | Page 65 |
| Which is the uppermost atmospheric layer? | Exosphere | Page 66 |
| Which atmospheric layer is most important for weather changes? | Troposphere | Page 65 |
| Which gas becomes negligible above 120 km? | Oxygen | Page 64 |
| Which weather element measures moisture in air? | Humidity | Page 66 |
| Which region has maximum troposphere thickness? | Equator | Page 65 |
Assertion (A): Atmosphere is essential for survival of organisms.
Reason (R): Atmosphere contains life-supporting gases like oxygen and carbon dioxide.
Options:
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Assertion (A): Carbon dioxide contributes to greenhouse effect.
Reason (R): Carbon dioxide absorbs terrestrial radiation and reflects part of it back to Earth.
Options:
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Assertion (A): Ozone layer is important for life on Earth.
Reason (R): Ozone absorbs harmful ultraviolet radiation from the Sun.
Options:
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Assertion (A): Water vapour acts like a blanket around Earth.
Reason (R): Water vapour preserves Earth’s radiated heat.
Options:
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Assertion (A): Dust particles help in cloud formation.
Reason (R): Dust particles act as hygroscopic nuclei around which condensation occurs.
Options:
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Assertion (A): Troposphere is the most important atmospheric layer for human life.
Reason (R): All weather and climate changes occur in troposphere.
Options:
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Assertion (A): Troposphere is thicker near the equator.
Reason (R): Strong convectional currents transport heat to greater heights near equator.
Options:
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Assertion (A): Temperature decreases with height in troposphere.
Reason (R): Troposphere receives heat mainly from Earth’s surface.
Options:
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Assertion (A): Stratosphere contains ozone layer.
Reason (R): Ozone layer protects life by absorbing ultraviolet rays.
Options:
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Assertion (A): Ionosphere is important for radio communication.
Reason (R): Radio waves are reflected back to Earth by ionosphere.
Options:
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Assertion (A): Mesosphere is extremely cold.
Reason (R): Temperature decreases with increasing altitude in mesosphere.
Options:
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Assertion (A): Water vapour amount varies from place to place.
Reason (R): Temperature and moisture conditions vary across regions.
Options:
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Assertion (A): Oxygen becomes negligible at greater heights.
Reason (R): Atmospheric composition changes with altitude.
Options:
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Assertion (A): Dust particles are more concentrated in subtropical and temperate regions.
Reason (R): Dry winds are more common in these regions.
Options:
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Assertion (A): Exosphere gradually merges with outer space.
Reason (R): Atmospheric contents become extremely rarefied at higher altitudes.
Options:
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Explain the meaning and importance of atmosphere.
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Describe the composition of atmosphere.
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Explain the importance of carbon dioxide in atmosphere.
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Discuss the causes and effects of greenhouse effect.
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Explain the role of ozone layer in protecting life on Earth.
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Describe the distribution and importance of water vapour in atmosphere.
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Explain the significance of dust particles in atmosphere.
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Describe the structure of atmosphere with suitable diagram explanation.
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Explain the characteristics of troposphere.
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Why is troposphere considered the most important atmospheric layer?
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Explain the concept of tropopause.
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Discuss the characteristics and importance of stratosphere.
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Explain the significance of ozone layer in stratosphere.
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Describe the characteristics of mesosphere.
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Explain the role of ionosphere in radio communication.
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Discuss the characteristics of exosphere.
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Differentiate between troposphere and stratosphere.
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Explain why atmospheric density decreases with altitude.
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Discuss the major elements of weather and climate.
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Explain how atmospheric composition supports life on Earth.
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