MCQs
1. The primary source of energy for Earth is:
A. Moon
B. Volcanoes
C. Sun
D. Oceans
Answer: C
2. The solid part of Earth consisting of rocks and
landforms is:
A. Hydrosphere
B. Atmosphere
C. Geosphere
D. Biosphere
Answer: C
3. Which sphere includes rivers, lakes and oceans?
A. Cryosphere
B. Hydrosphere
C. Atmosphere
D. Biosphere
Answer: B
4. Glaciers and polar ice caps belong to:
A. Geosphere
B. Biosphere
C. Cryosphere
D. Atmosphere
Answer: C
5. All living organisms together form the:
A. Hydrosphere
B. Biosphere
C. Cryosphere
D. Geosphere
Answer: B
6. The layer of air surrounding Earth is:
A. Biosphere
B. Atmosphere
C. Lithosphere
D. Cryosphere
Answer: B
7. Solar radiation reaches Earth in the form of:
A. Sound waves
B. Mechanical waves
C. Electromagnetic waves
D. Water waves
Answer: C
8. The speed of light in vacuum is:
c=3\times10^8\ \mathrm{m/s}
A. 3 × 10⁵ m/s
B. 3 × 10⁶ m/s
C. 3 × 10⁸ m/s
D. 3 × 10¹⁰ m/s
Answer: C
9. Which radiation is mostly absorbed by the ozone layer?
A. Infrared rays
B. Visible light
C. Ultraviolet rays
D. Radio waves
Answer: C
10. Visible light mainly helps in:
A. Nuclear reactions
B. Photosynthesis
C. Earthquakes
D. Magnetic storms
Answer: B
11. Greenhouse gases trap:
A. UV radiation only
B. Outgoing infrared radiation
C. Sound energy
D. Gamma rays
Answer: B
12. Which gas is a greenhouse gas?
A. Nitrogen
B. Oxygen
C. Carbon dioxide
D. Helium
Answer: C
13. The amount of solar radiation reaching Earth’s
surface is called:
A. Albedo
B. Insolation
C. Radiation balance
D. Refraction
Answer: B
14. The solar constant is approximately:
1.4\ \mathrm{kWm^{-2}}
A. 0.14 kWm⁻²
B. 1.4 kWm⁻²
C. 14 kWm⁻²
D. 140 kWm⁻²
Answer: B
15. Surfaces with high albedo:
A. Absorb more heat
B. Reflect more sunlight
C. Become hotter quickly
D. Emit gamma rays
Answer: B
16. Which surface has the highest albedo?
A. Ocean water
B. Black soil
C. Snow
D. Asphalt road
Answer: C
17. Cities become warmer than nearby rural areas due to:
A. Snowfall
B. Urban heat island effect
C. Photosynthesis
D. Polar winds
Answer: B
18. Equatorial regions receive more heat because:
A. Sunlight spreads over larger area
B. Sunlight falls more directly
C. Earth rotates faster there
D. Air is thinner
Answer: B
19. Most weather phenomena occur in the:
A. Stratosphere
B. Mesosphere
C. Troposphere
D. Exosphere
Answer: C
20. Ozone layer is mainly found in:
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
Answer: B
21. Valley breeze occurs:
A. During night
B. During daytime
C. During winter only
D. During rainfall only
Answer: B
22. Mountain breeze occurs:
A. During daytime
B. During night
C. At noon only
D. During storms only
Answer: B
23. Winds move from:
A. Low pressure to high pressure
B. High pressure to low pressure
C. Equator to Sun
D. Oceans to mountains only
Answer: B
24. Warm ocean currents generally move:
A. From poles to equator
B. From equator to poles
C. Vertically downward only
D. Toward deserts only
Answer: B
25. The cyclic movement of nutrients between living and
non-living components is:
A. Photosynthesis
B. Biogeochemical cycle
C. Respiration
D. Weathering
Answer: B
26. Water vapour changes into clouds by:
A. Evaporation
B. Condensation
C. Sublimation
D. Respiration
Answer: B
27. Plants absorb carbon dioxide during:
A. Respiration
B. Combustion
C. Photosynthesis
D. Decomposition
Answer: C
28. Nitrogen-fixing bacteria convert atmospheric nitrogen
into:
A. Oxygen
B. Ammonia
C. Carbon dioxide
D. Methane
Answer: B
29. Rhizobium bacteria are commonly found in:
A. Animal intestine
B. Root nodules of legumes
C. Ocean plankton
D. Human lungs
Answer: B
30. Excessive growth of algae due to fertilisers is
called:
A. Erosion
B. Denitrification
C. Eutrophication
D. Condensation
Answer: C
Assertion–Reason MCQs
31.
Assertion (A): Polar regions are colder than
equatorial regions.
Reason (R): Solar radiation spreads over a larger area near the poles.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
32.
Assertion (A): The atmosphere helps maintain suitable
temperature on Earth.
Reason (R): Greenhouse gases trap outgoing infrared radiation.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
33.
Assertion (A): Ocean currents influence climate.
Reason (R): They transport heat from equatorial regions to poles.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
34.
Assertion (A): Excessive fertiliser use can damage
aquatic ecosystems.
Reason (R): Nutrient enrichment causes algal blooms and oxygen
depletion.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
Case-Based MCQs
Case Study 1
A mountain town experiences cool air flowing downhill at
night.
35. This wind is called:
A. Valley breeze
B. Sea breeze
C. Mountain breeze
D. Trade wind
Answer: C
36. Mountain breeze forms because:
A. Slopes cool faster at night
B. Valley heats faster during day
C. Oceans cool rapidly
D. Sunlight becomes stronger
Answer: A
37. Such local winds mainly occur in:
A. Coastal plains
B. Desert regions
C. Mountainous areas
D. Polar regions
Answer: C
Case Study 2
Scientists observed increasing atmospheric carbon dioxide
levels over several decades.
38. Major reason for this increase is:
A. Photosynthesis
B. Burning fossil fuels
C. Nitrogen fixation
D. Condensation
Answer: B
39. Excess atmospheric CO₂ mainly leads to:
A. Cooling of Earth
B. Ozone formation only
C. Global warming
D. Increased snowfall everywhere
Answer: C
Competency-Based MCQs
40. If Earth had no atmosphere, the planet would:
A. Become warmer
B. Become too cold for life
C. Receive no sunlight
D. Stop rotating
Answer: B
41. Which atmospheric layer protects life by absorbing UV
radiation?
A. Troposphere
B. Mesosphere
C. Ozone layer in stratosphere
D. Thermosphere
Answer: C
42. Which process returns oxygen to atmosphere?
A. Respiration
B. Combustion
C. Photosynthesis
D. Denitrification
Answer: C
43. Which activity can reduce greenhouse gas emissions?
A. Deforestation
B. Burning coal
C. Using renewable energy
D. Increasing fossil fuel use
Answer: C
44. Why do dark surfaces heat faster?
A. They reflect more radiation
B. They absorb more solar radiation
C. They produce UV rays
D. They reduce greenhouse gases
Answer: B
45. Warm Arabian Sea water may affect:
A. Earthquakes
B. Southwest monsoon
C. Magnetic field
D. Ozone hole only
Answer: B
46. Which process in nitrogen cycle converts nitrates
back into nitrogen gas?
A. Assimilation
B. Nitrification
C. Denitrification
D. Ammonification
Answer: C
47. Plants and microbes help maintain ecosystem balance
mainly through:
A. Recycling nutrients
B. Producing plastic
C. Blocking sunlight
D. Increasing pollution
Answer: A
48. Which cycle directly connects glaciers, rainfall and
rivers?
A. Oxygen cycle
B. Nitrogen cycle
C. Water cycle
D. Carbon cycle
Answer: C
49. If forests are cleared, local rainfall may decrease
because:
A. Transpiration reduces
B. Oxygen increases
C. Soil becomes colder
D. UV radiation decreases
Answer: A
50. Which statement BEST explains Earth as a system?
A. Earth’s spheres work independently
B. Changes in one sphere can affect others
C. Only atmosphere controls climate
D. Oceans have no role in ecosystems
Answer: B
