Polar ice caps and glaciers have high albedo. If global warming causes significant melting of ice, exposing darker ocean or land, which feedback loop is most likely to occur?

C) Reduced albedo leads to more absorption of solar energy, causing further warming and more melting.

More ice forms because colder water refreezes, reversing global warming.

Exposed dark surfaces absorb less energy, cooling the region.

Reduced albedo leads to more absorption of solar energy, causing further warming and more melting.

Increased evaporation from open water forms more clouds, which reflect sunlight and stabilize temperature.

Consider the water cycle driven by solar energy. Which of the following sequences correctly describes the movement of water through the cycle?

A) Solar energy → Evaporation → Condensation → Precipitation → Runoff

Solar energy → Evaporation → Condensation → Precipitation → Runoff

Solar energy → Precipitation → Condensation → Evaporation → Runoff

Solar energy → Condensation → Evaporation → Precipitation → Runoff

Solar energy → Runoff → Evaporation → Condensation → Precipitation

On a sunny day, a black asphalt road feels much hotter than a light concrete pavement. Using the concept of albedo, which of the following best explains this?

C) The asphalt has a lower albedo, absorbing more solar radiation.

The asphalt has a higher albedo, absorbing less solar radiation.

The concrete has a lower albedo, absorbing more solar radiation.

The asphalt has a lower albedo, absorbing more solar radiation.

Both surfaces have the same albedo, but asphalt retains heat longer.

The warming of the Arabian Sea has been linked to changes in the Indian monsoon. Which of the following best explains how this warming affects the monsoon?

B) Warmer water increases evaporation, strengthening monsoon winds and causing more rainfall, but with variability across regions.

Warmer water reduces evaporation, weakening monsoon winds and reducing rainfall.

Warmer water increases evaporation, strengthening monsoon winds and causing more rainfall, but with variability across regions.

Warmer water increases evaporation uniformly, leading to equal rainfall distribution across India.

Warmer water absorbs more solar radiation, cooling the atmosphere and delaying the monsoon.

Assertion (A): The melting of Arctic sea ice can accelerate global warming through a positive feedback mechanism. Reason (R): Ice has a high albedo, so its replacement by darker ocean water increases absorption of solar radiation, leading to further warming.

Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is not the correct explanation of A.

A boy wears a black shirt and a white shirt on a sunny day. Which shirt will feel warmer and why?

The black shirt will feel warmer because it has a lower albedo, meaning it absorbs more solar radiation and reflects less, while the white shirt reflects most radiation.

Despite continuous input of solar energy, Earth's average temperature does not keep increasing indefinitely. Explain the role of Earth's radiation balance, greenhouse gases, and albedo in maintaining this stable temperature.

Earth radiates back infrared radiation into space. Some of this is trapped by greenhouse gases, warming the atmosphere. A balance is achieved between incoming solar radiation absorbed and outgoing terrestrial radiation. Albedo (reflected sunlight) also reduces absorbed energy. Changes in greenhouse gases or albedo can disturb this balance.

How does the albedo of a surface determine its temperature when exposed to sunlight? Provide one example from nature to support your explanation.

A surface with high albedo reflects most of the sunlight, so it absorbs less energy and remains cooler; a surface with low albedo absorbs more energy and becomes warmer. For example, snow has a high albedo (0.80–0.90) and stays cold, while dark ocean water has a low albedo and gets warmer.

If a large area of dark forest is replaced by a lighter-colored grassland, how might the local temperature change? Explain using the concept of albedo.

The grassland has a higher albedo than the dark forest, meaning it reflects more sunlight and absorbs less. This reduces the heat absorption, so the local temperature may decrease compared to when it was a forest.

Define the terms 'geosphere', 'hydrosphere', 'cryosphere', 'atmosphere', and 'biosphere'. Provide one specific example of an interaction between any two of these spheres that you might observe in your surroundings.

The geosphere refers to the solid Earth, including rocks, soil, and landforms. The hydrosphere includes all liquid water on Earth's surface, such as oceans, rivers, and groundwater. The cryosphere comprises frozen water in the form of ice and snow. The atmosphere is the layer of air surrounding the Earth. The biosphere encompasses all living organisms and their habitats. An example of interaction: Rain (hydrosphere) falling on mountains (geosphere) erodes rocks and carries sediments to rivers, which supports aquatic life (biosphere).

A geoengineering proposal suggests spraying fine seawater droplets into the atmosphere to increase the reflectivity of marine clouds. Evaluate how such an intervention might impact the Earth's spheres, including possible risks for the hydrosphere, cryosphere, and biosphere, particularly marine ecosystems.

Spraying seawater increases cloud condensation nuclei over oceans, creating brighter, more reflective clouds (higher albedo). This reflects more solar radiation, cooling the Earth. The hydrosphere: reduced sea surface temperatures could alter ocean currents and stratification, affecting nutrient upwelling. The cryosphere: cooling could slow ice melt, preserving glaciers and ice sheets, but if uneven, regional sea ice patterns might change. The biosphere: marine ecosystems depend on sunlight and temperature; reduced light could decrease phytoplankton photosynthesis, disrupting the marine food web. Also, changes in temperature and circulation may shift habitats for fish and corals. On land, altered rainfall patterns could affect forests and agriculture. Risks: unintended weather changes, droughts in some regions, and ethical concerns about large-scale atmospheric manipulation.

The Sun emits radiation across the electromagnetic spectrum, but mainly in the ultraviolet, visible, and infrared regions. The Earth's atmosphere filters out harmful high-energy radiation. (1) Which type of radiation is mostly absorbed by the ozone layer? (2) Why is visible light important for life on Earth? (3) Give one harmful effect and one beneficial use of ultraviolet radiation.

UV radiation is absorbed by the ozone layer. Visible light drives photosynthesis, the basis of food chains. UV can cause skin cancer but is useful in sterilisation.

Class 9 Science Chapter 13: Earth as a System – Energy, Matter and Life — Important Questions & Sample Paper

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Yes — this page has 44+ original Class 9 Science Chapter 13 (“Earth as a System – Energy, Matter and Life”) important questions with answers (Multiple Choice (MCQ), Assertion–Reason, Short Answer, Short Answer, Long Answer, Case Study). Practise them free, or generate a full CBSE board-pattern sample paper (80 marks) and export it to PDF or Word — in English & Hindi, for 2026-27.

Chapter 13, 'Earth as a System – Energy, Matter and Life', introduces students to the interconnected components of our planet. The chapter defines Earth as a dynamic system comprising five major spheres: the atmosphere, hydrosphere, lithosphere, biosphere, and cryosphere. It explains how solar energy drives vital processes like the water cycle and influences global temperature through the albedo effect—the reflectivity of surfaces. Students explore the greenhouse effect, which maintains Earth's habitable temperature, and learn how human actions, such as changing surface albedo or geoengineering, can impact these delicate balances. Exam questions often test understanding of these interactions, for example, tracing water movement in the water cycle, predicting temperature changes from painting roofs white, or evaluating the consequences of spraying seawater to brighten clouds. Students also apply concepts like atmospheric scattering and absorption to explain why surface insolation is lower than the solar constant, linking theory to real-world solar energy applications. This chapter builds foundational skills in systems thinking and environmental analysis, crucial for higher studies and competitive exams. By mastering the material through sample questions—from naming the spheres to justifying albedo-based cooling—learners develop the ability to reason about Earth's complex, life-sustaining processes.

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Science — Earth as a System – Energy, Matter and Life

Class 9Time: 3 hrsMax Marks: 80

SECTION A

1.
Polar ice caps and glaciers have high albedo. If global warming causes significant melting of ice, exposing darker ocean or land, which feedback loop is most likely to occur?
(a) More ice forms because colder water refreezes, reversing global warming.(b) Exposed dark surfaces absorb less energy, cooling the region.(c) Reduced albedo leads to more absorption of solar energy, causing further warming and more melting.(d) Increased evaporation from open water forms more clouds, which reflect sunlight and stabilize temperature.
1
2.
Consider the water cycle driven by solar energy. Which of the following sequences correctly describes the movement of water through the cycle?
(a) Solar energy → Evaporation → Condensation → Precipitation → Runoff(b) Solar energy → Precipitation → Condensation → Evaporation → Runoff(c) Solar energy → Condensation → Evaporation → Precipitation → Runoff(d) Solar energy → Runoff → Evaporation → Condensation → Precipitation
1
3.
On a sunny day, a black asphalt road feels much hotter than a light concrete pavement. Using the concept of albedo, which of the following best explains this?
(a) The asphalt has a higher albedo, absorbing less solar radiation.(b) The concrete has a lower albedo, absorbing more solar radiation.(c) The asphalt has a lower albedo, absorbing more solar radiation.(d) Both surfaces have the same albedo, but asphalt retains heat longer.
1

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Marks distribution & blueprint

In a CBSE exam, this chapter typically contributes questions across the following types. The last column shows how many original questions of each type we have ready in our bank for this chapter:

Question type	Marks each	In our bank
Multiple Choice (MCQ)	1 mark	13
Assertion–Reason	1 mark	6
Short Answer	2 marks	8
Short Answer	3 marks	6
Long Answer	5 marks	5
Case Study	4 marks	6

44 original, exam-style questions in our bank for this chapter — with answers.

Important & sample questions (with answers)

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Q1. Polar ice caps and glaciers have high albedo. If global warming causes significant melting of ice, exposing darker ocean or land, which feedback loop is most likely to occur?
1 mark
Multiple Choice (MCQ)
(A) More ice forms because colder water refreezes, reversing global warming.(B) Exposed dark surfaces absorb less energy, cooling the region.(C) Reduced albedo leads to more absorption of solar energy, causing further warming and more melting.(D) Increased evaporation from open water forms more clouds, which reflect sunlight and stabilize temperature.
▸ Answer▾ Answer
C) Reduced albedo leads to more absorption of solar energy, causing further warming and more melting.
Q2. Consider the water cycle driven by solar energy. Which of the following sequences correctly describes the movement of water through the cycle?
1 mark
Multiple Choice (MCQ)
(A) Solar energy → Evaporation → Condensation → Precipitation → Runoff(B) Solar energy → Precipitation → Condensation → Evaporation → Runoff(C) Solar energy → Condensation → Evaporation → Precipitation → Runoff(D) Solar energy → Runoff → Evaporation → Condensation → Precipitation
▸ Answer▾ Answer
A) Solar energy → Evaporation → Condensation → Precipitation → Runoff
Q3. On a sunny day, a black asphalt road feels much hotter than a light concrete pavement. Using the concept of albedo, which of the following best explains this?
1 mark
Multiple Choice (MCQ)
(A) The asphalt has a higher albedo, absorbing less solar radiation.(B) The concrete has a lower albedo, absorbing more solar radiation.(C) The asphalt has a lower albedo, absorbing more solar radiation.(D) Both surfaces have the same albedo, but asphalt retains heat longer.
▸ Answer▾ Answer
C) The asphalt has a lower albedo, absorbing more solar radiation.
Q4. The warming of the Arabian Sea has been linked to changes in the Indian monsoon. Which of the following best explains how this warming affects the monsoon?
1 mark
Multiple Choice (MCQ)
(A) Warmer water reduces evaporation, weakening monsoon winds and reducing rainfall.(B) Warmer water increases evaporation, strengthening monsoon winds and causing more rainfall, but with variability across regions.(C) Warmer water increases evaporation uniformly, leading to equal rainfall distribution across India.(D) Warmer water absorbs more solar radiation, cooling the atmosphere and delaying the monsoon.
▸ Answer▾ Answer
B) Warmer water increases evaporation, strengthening monsoon winds and causing more rainfall, but with variability across regions.
Q5. Assertion (A): The melting of Arctic sea ice can accelerate global warming through a positive feedback mechanism. Reason (R): Ice has a high albedo, so its replacement by darker ocean water increases absorption of solar radiation, leading to further warming.
1 mark
Assertion–Reason
(A) Both A and R are true and R is the correct explanation of A.(B) Both A and R are true but R is not the correct explanation of A.(C) A is true but R is false.(D) A is false but R is true.
▸ Answer▾ Answer
Both A and R are true and R is the correct explanation of A.
Q6. A boy wears a black shirt and a white shirt on a sunny day. Which shirt will feel warmer and why?
2 marks
Short Answer
▸ Answer▾ Answer
The black shirt will feel warmer because it has a lower albedo, meaning it absorbs more solar radiation and reflects less, while the white shirt reflects most radiation.
Q7. Despite continuous input of solar energy, Earth's average temperature does not keep increasing indefinitely. Explain the role of Earth's radiation balance, greenhouse gases, and albedo in maintaining this stable temperature.
2 marks
Short Answer
▸ Answer▾ Answer
Earth radiates back infrared radiation into space. Some of this is trapped by greenhouse gases, warming the atmosphere. A balance is achieved between incoming solar radiation absorbed and outgoing terrestrial radiation. Albedo (reflected sunlight) also reduces absorbed energy. Changes in greenhouse gases or albedo can disturb this balance.
Q8. How does the albedo of a surface determine its temperature when exposed to sunlight? Provide one example from nature to support your explanation.
3 marks
Short Answer
▸ Answer▾ Answer
A surface with high albedo reflects most of the sunlight, so it absorbs less energy and remains cooler; a surface with low albedo absorbs more energy and becomes warmer. For example, snow has a high albedo (0.80–0.90) and stays cold, while dark ocean water has a low albedo and gets warmer.
Q9. If a large area of dark forest is replaced by a lighter-colored grassland, how might the local temperature change? Explain using the concept of albedo.
3 marks
Short Answer
▸ Answer▾ Answer
The grassland has a higher albedo than the dark forest, meaning it reflects more sunlight and absorbs less. This reduces the heat absorption, so the local temperature may decrease compared to when it was a forest.
Q10. Define the terms 'geosphere', 'hydrosphere', 'cryosphere', 'atmosphere', and 'biosphere'. Provide one specific example of an interaction between any two of these spheres that you might observe in your surroundings.
5 marks
Long Answer
▸ Answer▾ Answer
The geosphere refers to the solid Earth, including rocks, soil, and landforms. The hydrosphere includes all liquid water on Earth's surface, such as oceans, rivers, and groundwater. The cryosphere comprises frozen water in the form of ice and snow. The atmosphere is the layer of air surrounding the Earth. The biosphere encompasses all living organisms and their habitats. An example of interaction: Rain (hydrosphere) falling on mountains (geosphere) erodes rocks and carries sediments to rivers, which supports aquatic life (biosphere).
Q11. A geoengineering proposal suggests spraying fine seawater droplets into the atmosphere to increase the reflectivity of marine clouds. Evaluate how such an intervention might impact the Earth's spheres, including possible risks for the hydrosphere, cryosphere, and biosphere, particularly marine ecosystems.
5 marks
Long Answer
▸ Answer▾ Answer
Spraying seawater increases cloud condensation nuclei over oceans, creating brighter, more reflective clouds (higher albedo). This reflects more solar radiation, cooling the Earth. The hydrosphere: reduced sea surface temperatures could alter ocean currents and stratification, affecting nutrient upwelling. The cryosphere: cooling could slow ice melt, preserving glaciers and ice sheets, but if uneven, regional sea ice patterns might change. The biosphere: marine ecosystems depend on sunlight and temperature; reduced light could decrease phytoplankton photosynthesis, disrupting the marine food web. Also, changes in temperature and circulation may shift habitats for fish and corals. On land, altered rainfall patterns could affect forests and agriculture. Risks: unintended weather changes, droughts in some regions, and ethical concerns about large-scale atmospheric manipulation.
Q12. The Sun emits radiation across the electromagnetic spectrum, but mainly in the ultraviolet, visible, and infrared regions. The Earth's atmosphere filters out harmful high-energy radiation.
4 marks
Case Study
1. (i) Which type of radiation is mostly absorbed by the ozone layer?1 mark
2. (ii) Why is visible light important for life on Earth?1 mark
3. (iii) Give one harmful effect and one beneficial use of ultraviolet radiation.2 marks
▸ Answer▾ Answer
UV radiation is absorbed by the ozone layer. Visible light drives photosynthesis, the basis of food chains. UV can cause skin cancer but is useful in sterilisation.

Frequently asked questions

What are the five major spheres of the Earth system?

The five spheres are the atmosphere (gaseous envelope), hydrosphere (all liquid water), lithosphere (solid Earth including soil and rock), biosphere (all living organisms), and cryosphere (frozen water regions like glaciers and ice sheets). They constantly exchange energy and matter.

How does the albedo effect influence Earth's temperature?

Albedo is the fraction of solar radiation reflected by a surface. High-albedo surfaces (e.g., ice, white rooftops) reflect more sunlight, causing cooling, while low-albedo surfaces (e.g., dark oceans, forests) absorb more heat, raising temperatures. Changes in albedo can alter local and global climate patterns.

Why is the solar constant at Earth's surface lower than at the top of the atmosphere?

The solar constant (~1.4 kW/m²) is reduced as sunlight passes through the atmosphere because of scattering by gases and aerosols, absorption by ozone, water vapor, and clouds, and reflection back to space. Under clear skies, maximum surface insolation is about 1 kW/m², which has direct implications for solar panel efficiency.

What is the greenhouse effect and why is it essential for life?

The greenhouse effect is the natural warming caused by atmospheric gases (like CO₂ and water vapor) that trap outgoing infrared radiation. Without it, Earth’s average surface temperature would be around -18°C instead of 15°C, making the planet too cold for most life forms to survive.

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