We have included 35 MCQs for Chapter 13 of the NCERT Science book. In this chapter, “Earth as a System: Energy, Matter, and Life”, you will explore how energy and matter move through the Earth’s interconnected spheres. Here we will also learn more about how natural processes maintain balance on our planet.
The questions cover concepts such as the Earth’s spheres, solar radiation, insolation, albedo, atmospheric layers, greenhouse effect, winds, ocean currents, and cycles including the water, carbon, nitrogen, and oxygen cycles.
Let’s have a look at some of the primary points that will help you scan the chapter quickly:
- Earth system includes geosphere, hydrosphere, atmosphere, biosphere, cryosphere.
- Sun is Earth’s primary energy source.
- Speed of light = 3 × 10⁸ m s⁻¹.
- Solar radiation mainly includes UV, visible, infrared.
- UV wavelength range: 100–400 nm.
- 1 nanometre (nm) = 10⁻⁹ m.
- Solar constant ≈ 1.4 kW m⁻².
- Clear-sky insolation ≈ 1 kW m⁻².
- Albedo measures reflected solar radiation fraction.
- High albedo surfaces remain cooler.
- Atmosphere contains 78% nitrogen and 21% oxygen.
- Troposphere extends up to about 12 km.
- Temperature decreases ~6.5°C per kilometre.
- Greenhouse gases include CO₂, CH₄, water vapour.
- Biogeochemical cycles recycle water, carbon, nitrogen, oxygen.
35 MCQ Questions for Class 9 Science: Chapter 13 Earth as a System: Energy, Matter, and Life
Question 1. Which is Earth’s primary energy source?
a) Moon
b) Sun
c) Volcanoes
d) Oceans
Answer:
b) Sun — Drives most Earth processes.
Question 2. Earth functions as a:
a) Closed system only
b) Open system
c) Dead system
d) Mechanical system
Answer:
b) Open system — Exchanges energy continuously.
Question 3. Which is NOT an Earth sphere?
a) Biosphere
b) Hydrosphere
c) Lithosphere
d) Astrosphere
Answer:
d) Astrosphere — Not Earth’s subsystem.
Question 4. The geosphere mainly consists of:
a) Air
b) Water
c) Solid Earth
d) Living organisms
Answer:
c) Solid Earth — Rocks and landforms.
Question 5. Hydrosphere includes:
a) Mountains
b) Rivers and oceans
c) Atmosphere
d) Soil only
Answer:
b) Rivers and oceans — Earth’s water bodies.
Question 6. Biosphere contains:
a) Rocks only
b) Living organisms
c) Clouds only
d) Ice only
Answer:
b) Living organisms — All forms of life.
Question 7. Cryosphere refers to:
a) Forests
b) Ice-covered regions
c) Oceans
d) Deserts
Answer:
b) Ice-covered regions — Frozen water stores.
Question 8. Speed of light is approximately:
a) 3×10⁵ m/s
b) 3×10⁶ m/s
c) 3×10⁸ m/s
d) 3×10¹⁰ m/s
Answer:
c) 3×10⁸ m/s — Solar energy travels fast.
Question 9. Solar radiation mainly contains:
a) UV, visible, infrared
b) X-rays only
c) Radio waves only
d) Gamma rays only
Answer:
a) UV, visible, infrared — Major solar spectrum.
Question 10. Visible light wavelength range is:
a) 400–700 nm
b) 10–100 nm
c) 700–1000 nm
d) 1–10 nm
Answer:
a) 400–700 nm — Human eye detects.
Question 11. One nanometre equals:
a) 10⁻³ m
b) 10⁻⁶ m
c) 10⁻⁹ m
d) 10⁻¹² m
Answer:
c) 10⁻⁹ m — Extremely small length.
Question 12. Solar constant is about:
a) 14 kW/m²
b) 1.4 kW/m²
c) 0.14 kW/m²
d) 140 kW/m²
Answer:
b) 1.4 kW/m² — At atmosphere’s edge.
Question 13. Insolation means:
a) Reflected radiation
b) Incoming solar radiation
c) Earth’s heat
d) Ocean energy
Answer:
b) Incoming solar radiation — Energy received.
Question 14. Clear-sky insolation is roughly:
a) 10 kW/m²
b) 5 kW/m²
c) 1 kW/m²
d) 0.1 kW/m²
Answer:
c) 1 kW/m² — Surface solar energy.
Question 15. Albedo measures:
a) Absorbed heat
b) Reflected radiation fraction
c) Wind speed
d) Rainfall
Answer:
b) Reflected radiation fraction — Surface reflectivity.
Question 16. Which surface has highest albedo?
a) Forest
b) Ocean
c) Fresh snow
d) Soil
Answer:
c) Fresh snow — Reflects most sunlight.
Question 17. Atmosphere contains about:
a) 50% nitrogen
b) 78% nitrogen
c) 90% oxygen
d) 30% carbon dioxide
Answer:
b) 78% nitrogen — Dominant atmospheric gas.
Question 18. Oxygen forms approximately:
a) 21%
b) 50%
c) 78%
d) 1%
Answer:
a) 21% — Essential for respiration.
Question 19. Lowest atmospheric layer is:
a) Mesosphere
b) Thermosphere
c) Troposphere
d) Stratosphere
Answer:
c) Troposphere — Weather occurs here.
Question 20. Troposphere extends up to about:
a) 2 km
b) 12 km
c) 50 km
d) 100 km
Answer:
b) 12 km — Average thickness.
Question 21. Temperature generally decreases by:
a) 1°C/km
b) 3°C/km
c) 6.5°C/km
d) 10°C/km
Answer:
c) 6.5°C/km — Environmental lapse rate.
Question 22. Ozone layer lies mainly in:
a) Troposphere
b) Stratosphere
c) Mesosphere
d) Exosphere
Answer:
b) Stratosphere — Absorbs harmful UV.
Question 23. Greenhouse effect helps:
a) Cool Earth drastically
b) Maintain Earth’s temperature
c) Remove atmosphere
d) Increase albedo
Answer:
b) Maintain Earth’s temperature — Supports life.
Question 24. Which is a greenhouse gas?
a) Nitrogen
b) Oxygen
c) Carbon dioxide
d) Helium
Answer:
c) Carbon dioxide — Traps heat.
Question 25. Methane chemical formula is:
a) CO₂
b) CH₄
c) N₂
d) O₂
Answer:
b) CH₄ — Potent greenhouse gas.
Question 26. Water cycle involves movement of:
a) Rocks
b) Water
c) Oxygen
d) Nitrogen
Answer:
b) Water — Continuous circulation.
Question 27. Evaporation converts:
a) Gas to liquid
b) Liquid to gas
c) Solid to liquid
d) Gas to solid
Answer:
b) Liquid to gas — Driven by heat.
Question 28. Condensation forms:
a) Clouds
b) Rocks
c) Soil
d) Wind
Answer:
a) Clouds — Water vapor cools.
Question 29. Carbon cycle transfers:
a) Water
b) Carbon compounds
c) Nitrogen only
d) Oxygen only
Answer:
b) Carbon compounds — Through ecosystems.
Question 30. Photosynthesis removes:
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Hydrogen
Answer:
b) Carbon dioxide — Used to make food.
Question 31. Nitrogen fixation converts nitrogen into:
a) Useful compounds
b) Oxygen
c) Water
d) Carbon dioxide
Answer:
a) Useful compounds — Plants can absorb.
Question 32. Rhizobium bacteria help in:
a) Photosynthesis
b) Nitrogen fixation
c) Respiration
d) Pollination
Answer:
b) Nitrogen fixation — Root nodule bacteria.
Question 33. Oxygen cycle is linked with:
a) Photosynthesis and respiration
b) Erosion only
c) Volcanism only
d) Weathering only
Answer:
a) Photosynthesis and respiration — Continuous exchange.
Question 34. Matter on Earth is mostly:
a) Created continuously
b) Recycled continuously
c) Destroyed permanently
d) Lost to space
Answer:
b) Recycled continuously — Through natural cycles.
Question 35. Earth system components are:
a) Independent only
b) Interconnected
c) Unrelated
d) Isolated
Answer:
b) Interconnected — Changes affect others.
10 True and False Questions for Chapter 13 Earth as a System: Energy, Matter, and Life
Question 1. The Sun is Earth’s primary energy source. (True/False)
Answer:
True
Question 2. The biosphere includes only plants. (True/False)
Answer:
False
Question 3. The cryosphere consists of Earth’s frozen water. (True/False)
Answer:
True
Question 4. One nanometre equals 10⁻⁹ metre. (True/False)
Answer:
True
Question 5. Albedo measures the absorption of sunlight. (True/False)
Answer:
False
Question 6. Nitrogen makes up most of Earth’s atmosphere. (True/False)
Answer:
True
Question 7. The ozone layer is located mainly in the troposphere. (True/False)
Answer:
False
Question 8. Carbon dioxide is a greenhouse gas. (True/False)
Answer:
True
Question 9. Photosynthesis removes carbon dioxide from the atmosphere. (True/False)
Answer:
True
Question 10. Matter on Earth is continuously recycled through natural cycles. (True/False)
Answer:
True
10 Fill in the Blanks Questions for Chapter 13 Earth as a System: Energy, Matter, and Life
Question 1. The __________ is the primary source of Earth’s energy.
Answer:
Sun
Question 2. The solid part of Earth is called the __________.
Answer:
Geosphere
Question 3. One nanometre is equal to __________ metre.
Answer:
10⁻⁹
Question 4. Incoming solar radiation is known as __________.
Answer:
Insolation
Question 5. The fraction of reflected solar radiation is called __________.
Answer:
Albedo
Question 6. The lowest layer of Earth’s atmosphere is the __________.
Answer:
Troposphere
Question 7. The gas that forms about 78% atmosphere is __________.
Answer:
Nitrogen
Question 8. Carbon dioxide is a __________ gas.
Answer:
Greenhouse
Question 9. The process converting liquid water into vapour is __________.
Answer:
Evaporation
Question 10. Rhizobium bacteria help in __________ fixation.
Answer:
Nitrogen
Question on Match the Columns
Unmatched Columns – Questions
| Column A | Column B |
|---|---|
| (i) Geosphere | (a) Incoming solar radiation |
| (ii) Insolation | (b) Fraction of reflected sunlight |
| (iii) Albedo | (c) Frozen water regions of Earth |
| (iv) Cryosphere | (d) Solid part of Earth |
| (v) Troposphere | (e) Lowest atmospheric layer |
| (vi) Rhizobium | (f) Nitrogen-fixing bacterium |
Matched Columns – Answer
| Column A | Column B |
|---|---|
| (i) Geosphere | (d) Solid part of Earth |
| (ii) Insolation | (a) Incoming solar radiation |
| (iii) Albedo | (b) Fraction of reflected sunlight |
| (iv) Cryosphere | (c) Frozen water regions of Earth |
| (v) Troposphere | (e) Lowest atmospheric layer |
| (vi) Rhizobium | (f) Nitrogen-fixing bacterium |
