How do differences in water density affect the vertical mobility of ocean currents? 1. Water with high salinity is less dense than water with low salinity. 2. Cold water is denser than warm water. 3. Denser water tends to rise while lighter water tends to sink. Which of the statements given above is/are correct?

The correct option is 2 only Explanation Ocean currents are influenced by various factors, including differences in water density. Density variations, primarily driven by temperature and salinity, play a crucial role in the vertical movement of ocean water, a process known as thermohaline circulation. Statement-wise Analysis 1. Statement 1: Water with high salinity is less dense than water with low salinity. Incorrect. Salinity increases the density of water. Water with higher salinity contains more dissolved salts per unit volume, making it denser than water with lower salinity at the same temperature. 2. Statement 2: Cold water is denser than warm water. Correct. As water cools, its molecules move closer together, increasing its density. Conversely, as water warms, its molecules spread out, decreasing its density. This principle is fundamental to thermohaline circulation, where cold, dense water sinks. 3. Statement 3: Denser water tends to rise while lighter water tends to sink. Incorrect. This statement reverses the fundamental principle of buoyancy. Denser water tends to sink, while lighter water tends to rise. This vertical movement is a key driver of ocean currents, as denser water displaces less dense water, causing it to move upwards. Key Takeaway Ocean water density is primarily determined by temperature and salinity; cold, saline water is denser and tends to sink, while warm, less saline water is lighter and tends to rise.

NCERT Class 11 Geography — Chapter 2: Movements of Ocean Water

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How do differences in water density affect the vertical mobility of ocean currents?

Water with high salinity is less dense than water with low salinity.
Cold water is denser than warm water.
Denser water tends to rise while lighter water tends to sink.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A2 and 3 only
B1, 2 and 3
C1 and 2 only
D2 only

Did you get this right?

Solution

The correct option is
2 only

Explanation

Ocean currents are influenced by various factors, including differences in water density. Density variations, primarily driven by temperature and salinity, play a crucial role in the vertical movement of ocean water, a process known as thermohaline circulation.

Statement-wise Analysis

Statement 1: Water with high salinity is less dense than water with low salinity.
Incorrect. Salinity increases the density of water. Water with higher salinity contains more dissolved salts per unit volume, making it denser than water with lower salinity at the same temperature.
Statement 2: Cold water is denser than warm water.
Correct. As water cools, its molecules move closer together, increasing its density. Conversely, as water warms, its molecules spread out, decreasing its density. This principle is fundamental to thermohaline circulation, where cold, dense water sinks.
Statement 3: Denser water tends to rise while lighter water tends to sink.
Incorrect. This statement reverses the fundamental principle of buoyancy. Denser water tends to sink, while lighter water tends to rise. This vertical movement is a key driver of ocean currents, as denser water displaces less dense water, causing it to move upwards.

Key Takeaway

Ocean water density is primarily determined by temperature and salinity; cold, saline water is denser and tends to sink, while warm, less saline water is lighter and tends to rise.

Your note

More from Chapter 2: Movements of Ocean Water

Consider the following factors: 1. The shape of bays and estuaries has no influence on the magnitude of tides. 2. Presence of wide continental shelves. 3. Presence of mid-oceanic islands. Which of the above factors can influence the height or magnitude of tidal bulges?

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Which of the following best describes the general movement of warm ocean currents?

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With reference to the movements of ocean water, consider the following statements: 1. Ocean currents represent the horizontal motion of water while tides represent the vertical motion. 2. In waves, the water moves ahead from one place to another along with the wave train. 3. The upwelling of cold water from the subsurface is a form of horizontal motion. Which of the statements given above is/are correct?

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Consider the following statements regarding the characteristics of ocean waves: 1. The largest waves are typically found in open oceans rather than enclosed seas. 2. Steep waves are generally old and originate from far away places. 3. Slow and steady waves usually originate from far away places. Which of the statements given above is/are correct?

medium

The maximum height of a wave is determined by which of the following factors? 1. The strength of the wind has no role in determining wave height. 2. The duration for which the wind blows. 3. The area over which the wind blows in a single direction. Select the correct answer using the code given below:

easy

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The correct option is
2 only

Explanation

Statement-wise Analysis

Statement 1: Water with high salinity is less dense than water with low salinity.
Incorrect. Salinity increases the density of water. Water with higher salinity contains more dissolved salts per unit volume, making it denser than water with lower salinity at the same temperature.
Statement 2: Cold water is denser than warm water.
Correct. As water cools, its molecules move closer together, increasing its density. Conversely, as water warms, its molecules spread out, decreasing its density. This principle is fundamental to thermohaline circulation, where cold, dense water sinks.
Statement 3: Denser water tends to rise while lighter water tends to sink.
Incorrect. This statement reverses the fundamental principle of buoyancy. Denser water tends to sink, while lighter water tends to rise. This vertical movement is a key driver of ocean currents, as denser water displaces less dense water, causing it to move upwards.

Key Takeaway

Ocean water density is primarily determined by temperature and salinity; cold, saline water is denser and tends to sink, while warm, less saline water is lighter and tends to rise.