Hydrosphere - Questions & Answers

1. Hydrosphere refers to the combined mass of water
(a) in the oceans
(b) rivers, streams and lakes
(c) in the atmosphere
(d) All of the above.
Answer: (d) All of the above.

2. Water is not usually thought of as a solid, and only a small fraction of the Earth's water is in a solid state, in the form of ice. This ice includes all forms of frozen water, from the ice sheets at the North and South poles to icebergs, ice on the top of mountains, frozen lakes in the winter, or even the ice in a freezer. Though all the ice on earth is part of the hydrosphere, the frozen aspect is known as the cryosphere. This frozen water is three-fourths of the earth's freshwater, which makes it quite important. Identify other sources of fresh water.
(a) rivers, lakes and streams
(b) underground water
(c) reservoirs and dams
(d) All of the above.
Answer: (d) All of the above.

3. Underground water is found in:
(a) soil
(b) subsoil
(c) underground streams
(d) All of the above.
Answer: (d) All of the above.

4. Assertion (A): Waves are oscillatory movements on the surface of the sea.
Reason (R): Waves result from the action of wind on the surface of the sea.
(a) Both A and R are true and R is the correct explanation of 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) Both A and R are true and R is the correct explanation of A.

5. Name the rise and fall of sea water due to the gravitational forces of the sun and the moon:
(a) Tides
(b) Waves
(c) Spheres
(d) Oscillations
Answer: (a) Tides

6. The difference in height between high tide and low tide is called _______
(a) Ebb
(b) Tidal wave
(c) Tidal range
(d) Tidal crest
Answer: (c) Tidal range

7. Apogee : Earth-moon distance _______ :: Perigee : Earth-moon distance _______
(a) maximum, minimum
(b) minimum, maximum
(c) equal, equal
(d) All of the above.
Answer: (a) maximum, minimum

8. Study the diagram and identify A and B.
(a) A: High tide B: Low tide
(b) A: Low tide B: Low tide
(c) A: Low tide B: High tide
(d) A: High tide B: High tide
Answer: (a) A: High tide B: Low tide

9. Assertion (A): Tidal range is not constant.
Reason (R): Tidal range varies due to the earth's rotation on its axis.
(a) Both A and R are true and R is the correct explanation of 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: (c) A is true but R is false.

10. Which of the following statements are true?
(1) The alternate advance and retreat of seawater along a coast is called tide.
(2) When water advances to its fullest extent on to the shore it is called high tide.
(3) When water recedes to its fullest extent from the shore it is called low tide.
(4) Some freshwater rivers and lakes can have tides too.
(a) (1) (2) (3) (4)
(b) Only (1)
(c) Only (2) and (3)
(d) (1) (2) and (3)
Answer: (a) (1) (2) (3) (4)

11. _______ flow from the lower latitudes towards the higher latitudes.
(a) Warm currents
(b) Cold currents
(c) Surface currents
(d) Deep water currents
Answer: (a) Warm currents

12. Which amongst the following is NOT one of the causes of Ocean Currents?
(a) Level of Salinity
(b) Temperature
(c) The Earth's Revolution
(d) Planetary Winds
Answer: (c) The Earth's Revolution

13. The water from the Atlantic ocean flows over the Mediterranean sea because
(a) The latter is more saline.
(b) The latter is warmer.
(c) of the direction of westerlies.
(d) of the earth's rotation.
Answer: (a) The latter is more saline.

14. Name the winds that blow between the Equator and the Tropics.
(a) Westerlies
(b) Trade Winds
(c) Monsoon Winds
(d) Summer Winds
Answer: (b) Trade Winds

15. What is the direction of air circulation over the oceans in the middle latitudes?
(a) Cyclonic
(b) Hemispherical
(c) Spherical
(d) Anticyclonic
Answer: (d) Anticyclonic

16. Assertion (A): Gulf stream flows in a clockwise direction.
Reason (R): In the Northern Hemisphere currents flow in a clockwise direction.
(a) Both A and R are true and R is the correct explanation of 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) Both A and R are true and R is the correct explanation of A.

17. Name the warm Atlantic Ocean Current which keeps the ports of Great Britain ice free even in winters.
(a) The West Atlantic Drift
(b) The East Atlantic Drift
(c) The North Atlantic Drift
(d) The South Atlantic Drift
Answer: (c) The North Atlantic Drift

18. Assertion (A): The Labrador Current remains frozen for nine months.
Reason (R): The cold Arctic Current is responsible for frozen seas of the Labrador Current.
(a) Both A and R are true and R is the correct explanation of 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) Both A and R are true and R is the correct explanation of A.

19. Identify the Warm Currents flowing in the Atlantic ocean.
(a) Gulf Stream — North Atlantic Drift
(b) Labrador Current — Irminger Current
(c) Canaries Current — Cayenne Current
(d) Alaska Current — California Current
Answer: (a) Gulf Stream — North Atlantic Drift

20. The Gulf Stream Current is deflected towards the east as a result of the earth's rotation and the westerlies to become the
(a) Labrador Current
(b) North Atlantic Drift
(c) Sargasso Sea
(d) Arctic Current
Answer: (b) North Atlantic Drift

21. Assertion (A): The water which gets collected under the surface of the land, known as underground water, remains in soil, sub-soil or bedrock.
Reason (R): The water from precipitation, that is from rain or snow flows on the surface.
(a) Both A and R are true and R is the correct explanation of 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: (b) Both A and R are true but R does not explain A.

22. Assertion (A): On the seventh or eighth day of every fortnight a neap tide, which is lower in height than a low tide, occurs.
Reason (R): The tide producing forces of the sun and the moon work in opposite direction causing a low tide.
(a) Both A and R are true and R is the correct explanation of 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: (d) A is false but R is true.

23. Which current is also known as the 'Black Stream'?
(a) Atlantic current
(b) Kuroshio current
(c) Oyashio current
(d) Newfoundland current
Answer: (b) Kuroshio current

24. Name the current that keeps the hub of world trade, the Port of Montreal, open all year round.
(a) Gulf Stream
(b) Labrador current
(c) Canaries current
(d) Florida current
Answer: (a) Gulf Stream

25. Which currents have created one of the world's richest fishing grounds?
(a) Labrador current and Gulf stream
(b) Labrador current and Irminger current
(c) Oyashio current and Kuroshio current
(d) Both (a) and (c).
Answer: (d) Both (a) and (c).

26. Assertion (A): Warm currents flow from the low latitudes in Tropical Zones towards the high latitudes.
Reason (R): They bring warm water into cold water areas.
(a) Both A and R are true and R is the correct explanation of 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: (b) Both A and R are true but R does not explain A.

27. Assertion (A): The air circulation over the oceans in the middle latitudes is mainly anticyclonic.
Reason (R): The oceanic circulation pattern corresponds with the circulation of air.
(a) Both A and R are true and R is the correct explanation of 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: (b) Both A and R are true but R does not explain A.

28. Currents influence which of the following?
(a) temperature
(b) rainfall
(c) fish population
(d) all of the above.
Answer: (d) all of the above.

1. Name any two ways in which movement of ocean water takes place.
Answer: Movement of ocean water takes place primarily through waves, tides, and currents. (Any two can be mentioned).

2. What are tides? Name one factor that causes tides.
Answer: Tides are the periodic rise and fall of sea water. They are primarily caused by the gravitational forces of the sun and the moon.

3. What is the time interval between tides? Name the factors responsible for this time interval.
Answer: Every place experiences a tide roughly after 12 hours and 26 minutes. The time interval and its 26-minute delay are caused by the Earth's rotation on its axis combined with the Moon's revolution around the Earth.

4. What are Spring and Neap tides?
Answer: Spring Tides are exceptionally high tides caused when the sun, the moon, and the earth are almost in a straight line. Neap Tides are lower than normal tides that occur when the sun and the moon are at right angles with reference to the earth.

5. Mona had gone to visit her friend's boat on the Visakhapatnam jetty. She was surprised to see that the boats seemed to have sunk because the water level in the jetty was low and the gangways to the boats were almost vertical. As a student of geography name and explain the phenomena that caused this.
Answer: The phenomenon is called an ebb or low tide. This happens when the sea water falls and moves back towards the sea, resulting in a significantly lower water level at the coast, which makes the docked boats sit much lower relative to the jetty.

6. Name two types of ocean currents based on their temperature. Give an example of each.
Answer: 1. Warm Currents, e.g., the Gulf Stream. 2. Cold Currents, e.g., the Labrador Current.

7. For what is the Gulf Stream famous?
Answer: The Gulf Stream is famous for being a powerful, warm ocean current that influences the climate of the North American east coast and keeps the ports of Western and Northern Europe ice-free even during harsh winters.

8. What happens when warm and cold currents meet?
Answer: When warm and cold ocean currents meet, they produce dense fogs that are highly dangerous for navigation. However, the mixing zones also concentrate organic material and attract plankton, turning them into some of the richest fishing grounds in the world.

9. Tara had gone to Canada to visit her cousins staying in Newfoundland. Her cousins took her to the seaside where they encountered heavy fog. As a student of geography Tara explained the cause of the fog. What did Tara say? What is the main occupation of the people in that place?
Answer: Tara explained that the dense fog is caused by the meeting of the warm Gulf Stream and the cold Labrador Current. The main occupation of the people in Newfoundland is fishing, because the mixing of these contrasting currents creates extremely rich fishing grounds.

1. (a) How are tides formed?
Answer: Tides are formed primarily due to the gravitational pull of the moon and the sun on the Earth's surface water. This gravitational attraction, along with the reactionary centrifugal force caused by the Earth's rotation, creates bulges in the ocean resulting in tides.

1. (b) Differentiate between High Tides and Low Tides.
Answer: High tide is the rise of sea water and its movement towards the coast, resulting in high water levels. Low tide (or ebb) is the fall of sea water and its retreat back towards the sea, resulting in low water levels.

1. (c) Give a reason for each of the following:
(i) There are two high and two low tides in a day.
Answer: As the earth rotates, the side facing the moon experiences a high tide due to gravitational pull. Simultaneously, the opposite side experiences a high tide due to the reactionary centrifugal force. As a place rotates through these two bulges and the two depressions between them, it experiences two high and two low tides daily.

(ii) Each day a tide is delayed by 26 minutes.
Answer: While the Earth rotates on its axis over 24 hours, the Moon is also revolving around the Earth. By the time the Earth completes one rotation, the Moon has moved further in its orbit. It takes the Earth an extra 52 minutes every 24 hours to "catch up", meaning each 12-hour tide cycle is delayed by 26 minutes.

(iii) The tidal range differs from one water body to the other.
Answer: The tidal range changes depending on the variable locations and alignments of the Moon and the Sun, which alter the intensity of tide-producing forces. Local geographic features of different water bodies also heavily influence how water behaves.

1. (d) Draw a well labelled diagram showing the formation of spring and neap tides.
Answer: [Diagram Requirement: Students are expected to draw the Earth, Moon, and Sun in a straight horizontal line to represent the combined gravitational pull of Spring Tides. A separate drawing should show the Moon at a right angle to the Earth and Sun to represent the opposing forces of Neap Tides.]

2. (a) Describing the two types of ocean currents based on their temperature.
Answer: 1. Warm Currents: These flow from low latitudes in the Tropical Zones towards high latitudes, bringing warm water into cold regions. 2. Cold Currents: These have a lower surface temperature and flow from high polar latitudes, bringing cold water into warm water areas.

2. (b) State any two factors responsible for causing the currents.
Answer: Two factors responsible for causing ocean currents are variations in the Level of Salinity and differences in Temperature across the oceans.

2. (c) Give a reason for each of the following:
(i) Warm currents produce a milder climate.
Answer: The air above a warm current becomes warm and acquires greater capacity to absorb moisture. When winds blow this warm, moist air over adjacent coastal areas, it raises local temperatures and brings rainfall, creating a milder climate.

(ii) The eastern coasts of USA are comparatively cold.
Answer: The eastern coasts of the USA are comparatively cold because they are influenced by the icy waters of the Labrador Current that flows southwards from the Arctic Ocean.

(iii) The coasts of Norway are not frozen in winter whereas its adjoining coasts are frozen for most parts of the year.
Answer: The coasts of Norway remain unfrozen because they are continually warmed by the North Atlantic Drift, a powerful warm current that keeps the coastal temperatures above freezing year-round.

2. (d) Describe one effect of each of the following three ocean currents.
(i) Labrador Current of the Atlantic Ocean.
Answer: It transports dangerous icebergs from Greenland southward into the transatlantic shipping lanes, posing a severe threat to commerce and ships.

(ii) The Kuroshio current
Answer: Its warm waters transport tropical warmth northward, sustaining the northernmost coral reefs in the world off the coast of Japan and keeping nearby ports ice-free.

(iii) Oyashio Current of the Pacific Ocean.
Answer: It brings extremely high nutrient contents southwards, helping to form some of the richest fishing grounds in the world when it meets warm currents.

3. (a) State the origin and flow of the Gulf Stream.
Answer: The Gulf Stream originates in the Gulf of Mexico, exits through the Strait of Florida, and flows northward along the eastern coastlines of the United States and Newfoundland. It then splits and crosses the Atlantic Ocean towards Europe.

3. (b) What is the effect of Gulf Stream on the coasts of North America and Western Europe?
Answer: It exerts a warming influence and brings rainfall to the eastern coast of North America. When it extends to Western Europe as the North Atlantic Drift, it provides a significantly warmer and milder climate and keeps European ports open and ice-free in the winter.

3. (c) Give a reason for each of the following:
(i) The waters of the Oyashio Current form the richest fishing grounds in the world.
Answer: The waters of the Oyashio Current have an extremely high nutrient content from cold water and large tides, which attracts massive amounts of plankton, subsequently creating rich feeding grounds for fish.

(ii) There is heavy rainfall in Queensland but the Atacama desert is arid.
Answer: Queensland receives heavy rainfall due to winds blowing over the warm East Australian Current. Conversely, the Atacama Desert is arid because the cold Peru Current flows near its coast, which cools the air and strongly discourages evaporation and rainfall.

(iii) Rich fishing grounds are located on the Pacific coast of North America.
Answer: Rich fishing grounds exist due to the circulation of cold, nutrient-rich water currents and their interactions with warmer water, which organically supports huge populations of plankton and fish.

3. (d) Describe three major effects of currents.
Answer: 1. Effect on Climate: They heavily modify the temperature and rainfall of the coastal regions they wash. 2. Effect on Marine Organisms: By moving organic materials and nutrients, they attract plankton and create rich fishing grounds. 3. Effect on Commerce: Warm currents keep high-latitude ports open year-round for trade, while cold currents can hinder commerce by introducing icebergs into shipping lanes.

1. You are watching the sea waves from the balcony of a seaside resort in Mumbai on a New Moon Day. Suddenly you noticed rise of sea water and its movement towards the coast. What was this wave and after how much time will it be repeated?
Answer: This sudden rise of sea water moving towards the coast is a High Tide (specifically a very high Spring Tide since it is a New Moon Day). The next high tide will be repeated after approximately 12 hours and 26 minutes.

2. Imagine that the Ocean Currents stop flowing. What would be its consequences for the human beings?
Answer: If ocean currents stopped flowing, the earth's climate would become violently imbalanced. Equatorial regions would become extremely hot while temperate and polar zones would become heavily frozen, disrupting global agriculture. Global trade and navigation would be crippled by frozen ports and unpredictable weather, and the fishing industry would collapse due to the lack of nutrient circulation required for marine life.

1. On an outline map of the world name and show the direction of one warm and one cold current each of the Pacific Ocean and the Atlantic Ocean.
Answer: [Map Work Task: Students should mark the Gulf Stream (warm, moving north-east) and the Labrador Current (cold, moving south) in the Atlantic Ocean. In the Pacific Ocean, students should mark the Kuroshio Current (warm, moving north) and the Oyashio Current (cold, moving south).]

2. Give a diagrammatic representation of the process of the rise and fall of tides.
Answer: [Diagram Work Task: Students should draw a spherical Earth surrounded by a layer of water, showing two large outward bulges of water (representing High Tides) on opposing sides caused by the Moon's gravitational pull and centrifugal force, and depressions at the top and bottom (representing Low Tides).]