Question 1

Q1: (i) Identify the element which is not a part of the hydrological cycle (a) Evaporation (b) Hydration (c) Precipitation (d) Condensation

Accepted Answer

(b) Hydration The hydrological cycle describes the movement of water and includes processes like evaporation, condensation, and precipitation, as mentioned in the chapter. Hydration, which is a chemical process of adding water to a substance, is not a part of this large-scale natural cycle.

Question 2

Q2: (ii) The average depth of continental slope varies between (a) 2-20 m (b) 200-2,000 m (c) 20-200 m (d) 2,000-20,000 m

Accepted Answer

(b) 200-2,000 m According to the chapter, the continental slope connects the continental shelf and the ocean basins. The text states that "The depth of the slope region varies between 200 and 3,000 m." The option 200-2,000 m is the closest range provided.

Question 3

Q3: (iii) Which one of the following is not a minor relief feature in the oceans: (a) Seamount (b) Atoll (c) Oceanic Deep (d) Guyot

Accepted Answer

(c) Oceanic Deep The chapter classifies the ocean floor into four major divisions: the Continental Shelf, the Continental Slope, the Deep Sea Plain, and the Oceanic Deeps. Features like seamounts, guyots, and atolls are listed under the category of 'Minor Relief Features'. Therefore, an Oceanic Deep...

Question 4

Q4: (iv) Salinity is expressed as the amount of salt in grams dissolved in sea water per (a) 10 gm (b) 1,000 gm (c) 100 gm (d) 10,000 gm

Accepted Answer

(b) 1,000 gm The text defines salinity as "the total content of dissolved salts in sea water." It further clarifies that "It is calculated as the amount of salt (in gm) dissolved in 1,000 gm (1 kg) of seawater."

Question 5

Q5: (v) Which one of the following is the smallest ocean: (a) Indian Ocean (b) Arctic Ocean (c) Atlantic Ocean (d) Pacific Ocean

Accepted Answer

(b) Arctic Ocean The chapter lists the five major oceans as the Pacific, the Atlantic, the Indian, the Southern, and the Arctic. Among these, the Arctic Ocean is the smallest in terms of area.

Question 6

Q1: (i) Why do we call the earth a Blue Planet?

Accepted Answer

The earth is called the 'Blue Planet' because of its abundant supply of water. Approximately 71 percent of the planet's surface is covered by water, primarily in the oceans, giving it a distinct blue appearance from space.

Question 7

Q2: (ii) What is a continental margin?

Accepted Answer

A continental margin is the extended edge of a continent that is submerged under the ocean. It consists of the continental shelf, which is the shallow, extended part of the landmass, and the continental slope, where the seafloor drops steeply to the deep ocean basin.

Question 8

Q3: (iii) List out the deepest trenches of various oceans.

Accepted Answer

The deepest trenches are areas of significant depth in the ocean floor. While the text notes that 32 trenches are in the Pacific, 19 in the Atlantic, and 6 in the Indian Ocean, it does not name them. The deepest known trenches are:    Pacific Ocean: Mariana Trench    Atlantic Ocean: Puerto Rico Tren...

Question 9

Q4: (iv) What is a thermocline?

Accepted Answer

A thermocline is a boundary region in the ocean, typically found below the surface layer, where there is a rapid decrease in water temperature with increasing depth. It separates the warmer upper layer of the ocean from the colder, deeper water below.

Question 10

Q5: (v) When you move into the ocean what thermal layers would you encounter? Why the temperature varies with depth?

Accepted Answer

Moving down into the ocean in middle and low latitudes, one encounters three thermal layers: a warm top layer, a thermocline layer where temperature drops rapidly, and a very cold deep layer. Temperature varies with depth because the sun's heat only penetrates the surface layers, and this heat is tr...

Question 11

Q6: (vi) What is salinity of sea water?

Accepted Answer

Salinity is the term used to define the total amount of dissolved mineral salts in seawater. It is typically expressed as parts per thousand (‰) and is calculated as the amount of salt in grams dissolved in 1,000 grams (1 kg) of seawater.

Question 12

Q1: (i) How are various elements of the hydrological cycle interrelated?

Accepted Answer

The various elements of the hydrological cycle are deeply interrelated, forming a continuous, circular movement of water on, above, and below the Earth's surface. The cycle is driven by solar energy. It begins with evaporation from water bodies like oceans, where liquid water turns into water vapor...

Question 13

Q2: (ii) Examine the factors that influence the temperature distribution of the oceans.

Accepted Answer

The temperature distribution of the oceans is influenced by several key factors that operate both globally and locally. These factors are:    Latitude: The primary factor is latitude. Since the amount of solar insolation decreases from the equator towards the poles, the surface water temperature of...

Question 14

Q1: (i) Consult the atlas and show ocean floor relief on the outline of the world map.

Accepted Answer

To complete this task, you would need an outline map of the world and an atlas with physical or bathymetric maps of the oceans. 1.  Continental Shelf: Lightly shade the shallow areas immediately adjacent to the continents. These are extensive in some areas, like the Siberian Shelf in the Arctic Ocea...

Question 15

Q2: (ii) Identify the areas of mid oceanic ridges from the Indian Ocean.

Accepted Answer

Using an atlas, one can identify the interconnected system of mid-oceanic ridges in the Indian Ocean. The main ridges form an inverted 'Y' shape: 1.  The Central Indian Ridge: This ridge runs in a north-south direction in the central Indian Ocean, separating the African Plate from the Indo-Australia...

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