NCERT Solutions Class 11 Geography Chapter 13: Movements of Ocean Water

NCERT Solutions Class 11 Geography Chapter 13 Movements of Ocean Water: are crafted to help students in preparing for their CBSE exams.

This chapter helps students learn about how water moves in the oceans. It talks about things like wind, temperature, and Earth’s rotation that make water move. With the help of these solutions, students can understand these topics better.

In this article, we are going to discuss the NCERT Solutions for Class 11 Geography Chapter 13: Movements of Ocean Water in detail.

NCERT Solutions of Class-11 Geography Chapter-13: Movements of Ocean Water

Exercises Page No: 125

Que 1. Multiple choice questions.

(i) Upward and downward movement of ocean water is known as the :

(a) tide (c) wave

(b) current (d) none of the above

Answer:

(a) tide

(ii) Spring tides are caused :

(a) As result of the moon and the sun pulling the earth gravitationally in the same direction.

(b) As result of the moon and the sun pulling the earth gravitationally in the opposite direction.

(c) Indention in the coast line.

(d) None of the above.

Answer:

(a) As result of the moon and the sun pulling the earth gravitationally in the same direction.

(iii) The distance between the earth and the moon is minimum when the moon is in :

(a) Aphelion (c) Perihelion

(b) Perigee (d) Apogee

Answer:

(b) Perigee

(iv) The earth reaches its perihelion in:

(a) October (c) July

(b) September (d) January

Answer:

(d) January

Que 2. Answer the following questions in about 30 words.

(i) What are waves?

Answer:

Waves are disturbances that propagate through a medium, often seen in oceans, lakes, and rivers, characterized by the transfer of energy without significant movement of mass.

(ii) Where do waves in the ocean get their energy from?

Answer:

Waves in the ocean derive their energy primarily from wind, which transfers energy to the water’s surface, creating waves.

(iii) What are tides?

Answer:

Tides are the periodic rise and fall of sea levels caused by gravitational forces exerted by the moon and the sun on Earth’s oceans.

(iv) How are tides caused?

Answer:

Tides are caused by the gravitational pull of the moon and the sun, which creates bulges in Earth’s oceans as they orbit around the planet.

(v) How are tides related to navigation?

Answer:

Tides affect water levels, impacting navigation by influencing the depth of water and currents in harbors, ports, and coastal areas, which sailors and navigators must consider for safe passage.

Que 3. Answer the following questions in about 150 words.

(i) How do currents affect the temperature? How does it affect the temperature of coastal areas in the N. W. Europe?

Answer:

Currents affect temperature by transporting heat from one region to another. In Northwest Europe, the North Atlantic Drift, an extension of the Gulf Stream, brings warm water from the tropics, moderating the climate and keeping coastal areas relatively warm compared to regions at similar latitudes. This is why places like the United Kingdom and Norway have milder winters despite being located at high latitudes.

(ii) What are the causes of currents?

Answer: Ocean currents are primarily caused by two forces:

Primary Forces:

• Heating by solar energy: Solar heating causes water to expand, creating slight gradients that induce water movement.
• Wind: Wind blowing over the ocean surface pushes water, creating friction that influences its movement.
• Gravity: Gravity pulls water down slopes, creating variations in gradients.
• Coriolis force: Earth’s rotation causes water to deflect, leading to the formation of gyres, large circular currents in ocean basins.

Secondary Forces:

• Difference in water density: Variations in density affect vertical mobility of ocean currents, with denser water sinking and lighter water rising.
• Difference in salinity: High salinity water is denser than low salinity water, similar to cold water being denser than warm water.

NCERT Solutions Class 11 Geography Chapter 13 Movements of Ocean Water Summary

Chapter 13 of Class 11 Geography talks about ocean currents, which are like rivers in the ocean. There are two main types: surface currents, which move on the top like wind-driven rivers, and deep ocean currents, which move below the surface.

These currents are caused by different things like wind, temperature, and Earth’s rotation. Wind pushes the water and makes surface currents. Differences in temperature and saltiness cause deep currents.

Ocean currents are important because they help move heat around the Earth, affecting weather and climate. They also influence where fish live and help ships navigate.

So, this chapter explains how ocean currents work and why they are important for our planet.

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NCERT Solutions Class 11 Geography Chapter 13 Movements of Ocean Water FAQs

What are ocean currents?

Ocean currents are continuous movements of seawater in the ocean, driven by factors such as wind, temperature, density, and Earth’s rotation.

What are the main types of ocean currents?

There are two main types of ocean currents: surface currents, which occur in the top layer of the ocean and are driven primarily by wind, and deep ocean currents, which circulate in the deeper layers of the ocean and are driven by differences in temperature and salinity.

What factors influence ocean currents?

Ocean currents are influenced by factors such as wind, temperature and density gradients, Earth’s rotation (Coriolis effect), and underwater topography.

Why are ocean currents important?

Ocean currents play a important role in regulating climate by redistributing heat around the globe. They also influence weather patterns, marine life, ecosystems, and human activities such as navigation and fishing.

How do ocean currents affect climate?

Ocean currents transport warm water from the equator to the poles and cold water from the poles to the equator, influencing temperature and weather patterns in different regions.

What is the Coriolis effect and how does it influence ocean currents?

The Coriolis effect is the deflection of moving objects, including ocean currents, caused by Earth’s rotation. In the Northern Hemisphere, currents are deflected to the right, while in the Southern Hemisphere, they are deflected to the left.