These Water (Oceans) Important Questions cover the most important MCQs, one-word questions, assertion and reason questions and descriptive questions from NCERT Class 11 Geography Chapter 12. The questions are prepared from NCERT concepts and important exam-oriented topics for quick revision and practice.
This page is useful for UPSC, SSC, PSC, Railway, CUET and Class 11 Geography preparation, helping students revise important concepts related to oceans, ocean relief, ocean temperature, salinity, ocean movements and marine circulation.
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Download Revision PDFs →These MCQs from Water (Oceans) are designed for quick objective revision and competitive exam preparation. The questions cover important oceanographic concepts, ocean relief features, salinity, temperature and ocean circulation discussed in the NCERT chapter.
MCQ 1: About how much percentage of Earth’s surface is covered by water?
A. 51%
B. 61%
C. 71%
D. 81%
Answer: C. 71% | Page Reference: Page 104
MCQ 2: The Pacific Ocean is the:
A. Smallest ocean
B. Deepest and largest ocean
C. Warmest ocean only
D. Saltiest ocean only
Answer: B. Deepest and largest ocean | Page Reference: Page 104
MCQ 3: The average depth of oceans is approximately:
A. 1000 metres
B. 2500 metres
C. 3800 metres
D. 7000 metres
Answer: C. 3800 metres | Page Reference: Page 104
MCQ 4: The continental shelf is:
A. Deep ocean trench
B. Gently sloping submerged extension of continent
C. Mid-ocean ridge
D. Volcanic island only
Answer: B. Gently sloping submerged extension of continent | Page Reference: Page 105
MCQ 5: The continental slope connects:
A. Ocean trenches and ridges
B. Continental shelf and deep ocean floor
C. Islands and coral reefs
D. Rivers and deltas only
Answer: B. Continental shelf and deep ocean floor | Page Reference: Page 105
MCQ 6: The deep ocean floor is also called:
A. Abyssal plain
B. Continental shelf
C. Lagoon
D. Coral reef
Answer: A. Abyssal plain | Page Reference: Page 105
MCQ 7: The Mariana Trench is located in:
A. Atlantic Ocean
B. Indian Ocean
C. Pacific Ocean
D. Arctic Ocean
Answer: C. Pacific Ocean | Page Reference: Page 106
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MCQ 8: Mid-oceanic ridges are mainly formed due to:
A. Sediment deposition
B. Plate tectonic activity
C. River erosion
D. Coral growth only
Answer: B. Plate tectonic activity | Page Reference: Page 106
MCQ 9: Ocean water salinity is measured in:
A. Percentages only
B. Parts per thousand
C. Kilometres
D. Degrees Celsius
Answer: B. Parts per thousand | Page Reference: Page 107
MCQ 10: Average salinity of ocean water is about:
A. 15‰
B. 25‰
C. 35‰
D. 50‰
Answer: C. 35‰ | Page Reference: Page 107
MCQ 11: Salinity increases with:
A. Heavy rainfall
B. River inflow
C. High evaporation
D. Ice melting only
Answer: C. High evaporation | Page Reference: Page 107
MCQ 12: Ocean temperature decreases with increasing:
A. Salinity only
B. Depth
C. Wind speed only
D. Tides only
Answer: B. Depth | Page Reference: Page 108
MCQ 13: The boundary separating warm surface water and cold deep water is called:
A. Thermocline
B. Halocline
C. Pycnocline
D. Shelf break
Answer: A. Thermocline | Page Reference: Page 108
MCQ 14: Horizontal movement of ocean water is called:
A. Tide
B. Ocean current
C. Wave
D. Tsunami
Answer: B. Ocean current | Page Reference: Page 109
MCQ 15: Warm ocean currents generally move from:
A. Poles to equator
B. Equator to poles
C. East to west only
D. West to east only
Answer: B. Equator to poles | Page Reference: Page 109
MCQ 16: The Gulf Stream is a:
A. Cold current
B. Warm current
C. Polar current
D. Tidal current only
Answer: B. Warm current | Page Reference: Page 109
MCQ 17: The Labrador Current is a:
A. Warm current
B. Cold current
C. Equatorial current
D. Monsoon current
Answer: B. Cold current | Page Reference: Page 109
MCQ 18: Ocean waves are mainly generated by:
A. Earthquakes only
B. Winds
C. Volcanic eruptions only
D. Salinity changes only
Answer: B. Winds | Page Reference: Page 110
MCQ 19: Tides are caused mainly by:
A. Ocean currents only
B. Gravitational pull of Moon and Sun
A. Earthquakes only
D. Volcanoes only
Answer: B. Gravitational pull of Moon and Sun | Page Reference: Page 111
MCQ 20: The highest tides are called:
A. Neap tides
B. Spring tides
C. Ebb tides
D. Drift tides
Answer: B. Spring tides | Page Reference: Page 111
MCQ 21: Neap tides occur when:
A. Sun, Moon and Earth are in straight line
B. Moon and Sun pull at right angles
C. Earth rotates fastest
D. Cyclones occur only
Answer: B. Moon and Sun pull at right angles | Page Reference: Page 111
MCQ 22: Tsunamis are mainly caused by:
A. Strong winds
B. Underwater earthquakes
C. High tides
D. Heavy rainfall only
Answer: B. Underwater earthquakes | Page Reference: Page 110
MCQ 23: Coral reefs are mainly formed in:
A. Cold polar waters
B. Warm shallow tropical waters
C. Deep ocean trenches
D. Freshwater lakes only
Answer: B. Warm shallow tropical waters | Page Reference: Page 106
MCQ 24: The continental shelf is economically important because of:
A. Dense forests only
B. Rich fishing grounds and mineral resources
C. Earthquake zones only
D. Glacier formation only
Answer: B. Rich fishing grounds and mineral resources | Page Reference: Page 105
MCQ 25: Which factor lowers salinity?
A. High evaporation
B. Low rainfall
C. Freshwater inflow
D. High temperature only
Answer: C. Freshwater inflow | Page Reference: Page 107
MCQ 26: The movement of ocean water due to wind friction is mainly called:
A. Tide
B. Current
C. Tsunami
D. Upwelling only
Answer: B. Current | Page Reference: Page 109
MCQ 27: Warm ocean currents generally influence nearby coasts by:
A. Cooling temperatures
B. Increasing temperature and humidity
C. Reducing rainfall completely
D. Causing deserts only
Answer: B. Increasing temperature and humidity | Page Reference: Page 109
MCQ 28: Cold currents generally lead to:
A. Increased rainfall
B. Lower coastal temperatures
C. Cyclone formation only
D. Tidal waves only
Answer: B. Lower coastal temperatures | Page Reference: Page 109
MCQ 29: The rise and fall of ocean water is called:
A. Ocean current
B. Wave motion
C. Tides
D. Thermocline
Answer: C. Tides | Page Reference: Page 111
MCQ 30: The deepest parts of oceans are generally:
A. Continental shelves
B. Abyssal plains
C. Ocean trenches
D. Coral reefs
Answer: C. Ocean trenches | Page Reference: Page 106
These one-word and factual questions help students quickly revise important oceanographic concepts, ocean relief features and ocean movements from the chapter. The section is especially useful for UPSC, SSC, PSC, Railway, CUET and other objective examinations.
- How much of Earth’s surface is covered by water?
Answer: 71% | Page Reference: Page 104 - Which is the largest ocean?
Answer: Pacific Ocean | Page Reference: Page 104 - What is the submerged extension of continent called?
Answer: Continental shelf | Page Reference: Page 105 - Which feature connects shelf and deep ocean floor?
Answer: Continental slope | Page Reference: Page 105 - What is the deep ocean floor called?
Answer: Abyssal plain | Page Reference: Page 105 - Which is the deepest ocean trench?
Answer: Mariana Trench | Page Reference: Page 106 - In which unit is salinity measured?
Answer: Parts per thousand | Page Reference: Page 107 - What is average ocean salinity?
Answer: 35‰ | Page Reference: Page 107 - Which layer separates warm and cold ocean water?
Answer: Thermocline | Page Reference: Page 108 - What is horizontal movement of ocean water called?
Answer: Ocean current | Page Reference: Page 109 - Which warm current flows in Atlantic Ocean?
Answer: Gulf Stream | Page Reference: Page 109 - Which cold current flows near Canada?
Answer: Labrador Current | Page Reference: Page 109 - What mainly generates ocean waves?
Answer: Winds | Page Reference: Page 110 - What causes tides?
Answer: Gravitational pull of Moon and Sun | Page Reference: Page 111 - Which tides are highest?
Answer: Spring tides | Page Reference: Page 111 - Which tides occur during right-angle position of Moon and Sun?
Answer: Neap tides | Page Reference: Page 111 - Which giant sea waves are caused by underwater earthquakes?
Answer: Tsunami | Page Reference: Page 110 - Where are coral reefs mainly found?
Answer: Warm shallow tropical waters | Page Reference: Page 106 - Which factor increases salinity?
Answer: Evaporation | Page Reference: Page 107 - Which ocean feature is economically important for fishing?
Answer: Continental shelf | Page Reference: Page 105
These assertion and reason questions from Water (Oceans) help students develop conceptual clarity and analytical understanding of ocean relief, salinity, currents and oceanic movements. They are highly useful for board exams and competitive examinations.
Question 1
Assertion (A): Continental shelves are economically important regions.
Reason (R): Rich fishing grounds and mineral resources are found on continental shelves.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 105
Question 2
Assertion (A): Salinity increases in regions of high evaporation.
Reason (R): Evaporation removes water but leaves salts behind.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 107
Question 3
Assertion (A): Ocean temperature decreases with depth.
Reason (R): Sunlight penetrates only upper layers of ocean water.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 108
Question 4
Assertion (A): Thermocline separates warm and cold ocean water.
Reason (R): Temperature changes rapidly across thermocline zone.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 108
Question 5
Assertion (A): Warm ocean currents increase coastal temperatures.
Reason (R): Warm currents transport heat from equatorial regions.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 109
Question 6
Assertion (A): Cold ocean currents lower temperatures of nearby coasts.
Reason (R): Cold currents originate from higher latitudes.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 109
Question 7
Assertion (A): Ocean waves are mainly generated by winds.
Reason (R): Friction between air and water transfers energy to ocean surface.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 110
Question 8
Assertion (A): Tsunamis are highly destructive ocean waves.
Reason (R): Underwater earthquakes displace large volumes of water suddenly.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 110
Question 9
Assertion (A): Tides are caused by gravitational pull of Moon and Sun.
Reason (R): Gravitational attraction affects ocean water levels on Earth.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 111
Question 10
Assertion (A): Spring tides are higher than neap tides.
Reason (R): Gravitational pull of Sun and Moon acts together during spring tides.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 111
Question 11
Assertion (A): Neap tides occur during first and third quarter moon phases.
Reason (R): Sun and Moon pull at right angles during neap tides.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 111
Question 12
Assertion (A): Coral reefs grow mainly in warm shallow waters.
Reason (R): Coral organisms require sunlight and warm temperatures.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 106
Question 13
Assertion (A): Mid-oceanic ridges are associated with tectonic activity.
Reason (R): Divergent plate boundaries create new oceanic crust.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 106
Question 14
Assertion (A): Freshwater inflow lowers ocean salinity.
Reason (R): Rivers dilute salt concentration in ocean water.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 107
Question 15
Assertion (A): Pacific Ocean is the deepest ocean.
Reason (R): Mariana Trench is located in Pacific Ocean.
A. Both A and R are true and R is the correct explanation
B. Both A and R are true but R is not the correct explanation
C. A is true but R is false
D. A is false but R is true
Correct Option: A | Page Reference: Page 104–106
These important descriptive and analytical questions from Water (Oceans) are useful for board examinations and competitive exams. The questions focus on conceptual understanding, ocean relief, salinity and oceanic circulation.
- Explain the importance of oceans on Earth.
Page Reference: Page 104 - Describe the major relief features of ocean floor.
Page Reference: Page 105–106 - Explain the characteristics and importance of continental shelves.
Page Reference: Page 105 - Discuss the formation and significance of ocean trenches.
Page Reference: Page 106 - Explain the formation of mid-oceanic ridges.
Page Reference: Page 106 - Discuss the causes and distribution of ocean salinity.
Page Reference: Page 107 - Explain the factors affecting ocean temperature.
Page Reference: Page 108 - Describe the concept and significance of thermocline.
Page Reference: Page 108 - Explain the causes and characteristics of ocean currents.
Page Reference: Page 109 - Differentiate between warm and cold ocean currents.
Page Reference: Page 109 - Discuss the influence of ocean currents on climate.
Page Reference: Page 109 - Explain the formation and characteristics of ocean waves.
Page Reference: Page 110 - Describe the causes and effects of tsunamis.
Page Reference: Page 110 - Explain the causes of tides.
Page Reference: Page 111 - Differentiate between spring tides and neap tides.
Page Reference: Page 111 - Discuss the economic importance of oceans.
Page Reference: Page 104–111 - Explain the role of oceans in regulating climate.
Page Reference: Page 108–109 - Describe the importance of coral reefs in marine ecosystem.
Page Reference: Page 106 - Explain how salinity influences ocean circulation.
Page Reference: Page 107–109 - Discuss the relationship between oceanic movements and coastal environments.
Page Reference: Page 109–111
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