These Water (Oceans) Important Questions cover important NCERT concepts related to oceans, ocean relief features, salinity, ocean temperature, waves, tides and ocean currents.
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 104–111
These MCQs from Water (Oceans) help students revise important oceanographic concepts related to ocean relief, salinity, tides, waves and ocean currents.
About how much percentage of Earth’s surface is covered by water?
Page Reference: Page 104
The Pacific Ocean is the:
Page Reference: Page 104
The average depth of oceans is approximately:
Page Reference: Page 104
The continental shelf is:
Page Reference: Page 105
The continental slope connects:
Page Reference: Page 105
The deep ocean floor is also called:
Page Reference: Page 105
The Mariana Trench is located in:
Page Reference: Page 106
Mid-oceanic ridges are mainly formed due to:
Page Reference: Page 106
Ocean water salinity is measured in:
Page Reference: Page 107
Average salinity of ocean water is about:
Page Reference: Page 107
Salinity increases with:
Page Reference: Page 107
Ocean temperature decreases with increasing:
Page Reference: Page 108
The boundary separating warm surface water and cold deep water is called:
Page Reference: Page 108
Horizontal movement of ocean water is called:
Page Reference: Page 109
Warm ocean currents generally move from:
Page Reference: Page 109
The Gulf Stream is a:
Page Reference: Page 109
The Labrador Current is a:
Page Reference: Page 109
Ocean waves are mainly generated by:
Page Reference: Page 110
Tides are caused mainly by:
Page Reference: Page 111
The highest tides are called:
Page Reference: Page 111
| Question | Answer | Page Reference |
|---|---|---|
| How much of Earth’s surface is covered by water? | 71% | Page 104 |
| Which is the largest ocean? | Pacific Ocean | Page 104 |
| What is the submerged extension of continent called? | Continental shelf | Page 105 |
| Which feature connects shelf and deep ocean floor? | Continental slope | Page 105 |
| What is the deep ocean floor called? | Abyssal plain | Page 105 |
| Which is the deepest ocean trench? | Mariana Trench | Page 106 |
| In which unit is salinity measured? | Parts per thousand | Page 107 |
| What is average ocean salinity? | 35‰ | Page 107 |
| Which layer separates warm and cold ocean water? | Thermocline | Page 108 |
| What is horizontal movement of ocean water called? | Ocean current | Page 109 |
| Which warm current flows in Atlantic Ocean? | Gulf Stream | Page 109 |
| Which cold current flows near Canada? | Labrador Current | Page 109 |
| What mainly generates ocean waves? | Winds | Page 110 |
| What causes tides? | Gravitational pull of Moon and Sun | Page 111 |
| Which tides are highest? | Spring tides | Page 111 |
| Which tides occur during right-angle position of Moon and Sun? | Neap tides | Page 111 |
| Which giant sea waves are caused by underwater earthquakes? | Tsunami | Page 110 |
| Where are coral reefs mainly found? | Warm shallow tropical waters | Page 106 |
| Which factor increases salinity? | Evaporation | Page 107 |
| Which ocean feature is economically important for fishing? | Continental shelf | Page 105 |
Assertion (A): Continental shelves are economically important regions.
Reason (R): Rich fishing grounds and mineral resources are found on continental shelves.
Options:
Page Reference: Page 105
Assertion (A): Salinity increases in regions of high evaporation.
Reason (R): Evaporation removes water but leaves salts behind.
Options:
Page Reference: Page 107
Assertion (A): Ocean temperature decreases with depth.
Reason (R): Sunlight penetrates only upper layers of ocean water.
Options:
Page Reference: Page 108
Assertion (A): Thermocline separates warm and cold ocean water.
Reason (R): Temperature changes rapidly across thermocline zone.
Options:
Page Reference: Page 108
Assertion (A): Warm ocean currents increase coastal temperatures.
Reason (R): Warm currents transport heat from equatorial regions.
Options:
Page Reference: Page 109
Assertion (A): Cold ocean currents lower temperatures of nearby coasts.
Reason (R): Cold currents originate from higher latitudes.
Options:
Page Reference: Page 109
Assertion (A): Ocean waves are mainly generated by winds.
Reason (R): Friction between air and water transfers energy to ocean surface.
Options:
Page Reference: Page 110
Assertion (A): Tsunamis are highly destructive ocean waves.
Reason (R): Underwater earthquakes displace large volumes of water suddenly.
Options:
Page Reference: Page 110
Assertion (A): Tides are caused by gravitational pull of Moon and Sun.
Reason (R): Gravitational attraction affects ocean water levels on Earth.
Options:
Page Reference: Page 111
Assertion (A): Spring tides are higher than neap tides.
Reason (R): Gravitational pull of Sun and Moon acts together during spring tides.
Options:
Page Reference: Page 111
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