Source: NCERT Official Textbook
This cycle is crucial for sustaining life, but increasing demand and pollution are leading to a global water crisis. The second major section details the Relief of the Ocean Floor, revealing a topography as varied as that on land. The ocean floor is divided into four major divisions: the shallow Continental Shelf, the steep Continental Slope, the vast and flat Deep Sea Plain, and the extremely deep Oceanic Deeps or Trenches.
The chapter also explains minor features like Mid-Oceanic Ridges, Seamounts, Submarine Canyons, Guyots (flat-topped seamounts), and Atolls (coral islands). Finally, the chapter examines the physical properties of seawater: Temperature and Salinity.
It analyzes the factors affecting ocean temperature distribution, such as latitude, land/water distribution, winds, and currents, and explains the vertical temperature profile featuring the Thermocline.
Salinity—the total dissolved salts in seawater—is defined, and its horizontal and vertical variations are discussed in relation to evaporation, precipitation, river inflow, and ocean currents. The chapter underscores the interrelationship between the ocean’s physical properties and its role in the Earth’s systems.
The hydrological cycle describes the movement of water: (Pg. 2)
Which is the shallowest part of the ocean with an average gradient of 1° or less? (Pg. 3)
The continental slope connects the: (Pg. 4)
Which ocean has the highest number of explored deeps? (Pg. 4)
What is a flat-topped seamount called? (Pg. 5)
Which factor causes upwelling of cold water, lowering coastal temperatures? (Pg. 5)
Why do oceans in the northern hemisphere record relatively higher temperatures than those in the southern hemisphere? (Pg. 6)
Which of the following factors does NOT directly affect the surface salinity of oceans? (Pg. 6)
(Exercise) Identify the element which is not a part of the hydrological cycle: (Pg. 8)
(Exercise) The average depth of the continental slope varies between: (Pg. 8)
(Exercise) Which one is NOT a minor relief feature in the oceans? (Pg. 9)
(Exercise) Salinity is expressed as the amount of salt in grams dissolved in sea water per: (Pg. 9)
(Exercise) Which one is the smallest ocean? (Pg. 9)
About ______ per cent of the planetary water is found in the oceans. (Pg. 3) Page 101
The steep slope where the continental shelf typically ends is called the ______. (Pg. 3) Page 101
Deep sea plains are the ______ and smoothest regions of the world. (Pg. 4) Page 102
A mountain with a pointed summit rising from the seafloor but not reaching the ocean surface is called a ______. (Pg. 4) Page 102
Low islands in tropical oceans consisting of coral reefs surrounding a central depression are called ______. (Pg. 5) Page 103
The boundary region in the ocean where temperature decreases rapidly with depth is called the ______. (Pg. 5) Page 103
The average temperature of the ocean surface water is about ______ °C. (Pg. 6) Page 104
Salinity is usually expressed as parts per thousand or ______. (Pg. 6) Page 104
(Exercise) The earth is called the ‘Blue Planet’ because of its abundant supply of ______. (Pg. 9) Page 107
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