CBSE Class 11 Fundamental of Physical Geography NCERT Solutions Chapter 14

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NCERT Solutions PDF Class 11 PDF

This chapter delves into the dynamic 'Movements of Ocean Water' for CBSE Class 11 Fundamental of Physical Geography. It provides detailed NCERT Solutions covering essential concepts like waves, tides, and ocean currents. Students will learn about the causes and characteristics of these phenomena, including the factors influencing wave energy, the gravitational forces behind tides, and the impact of currents on climate. The solutions offer clear explanations and step-by-step answers to help students grasp complex oceanic processes. These solutions are designed to aid in thorough exam revision, ensuring a strong understanding of oceanography for the upcoming examinations.

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BoardCBSE
ClassClass 11
SubjectFundamental of Physical Geography
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 14

Chapter summary

Chapter 14 of Fundamental of Physical Geography focuses on the crucial topic of 'Movements of Ocean Water'. The NCERT Solutions provided here explain the formation and characteristics of ocean waves, the causes and types of tides (including spring tides and neap tides), and the nature of ocean currents. It also elaborates on how these movements, particularly currents, influence global temperatures and climate, with specific examples like the North Atlantic Drift affecting Europe. The solutions aim to clarify these concepts for Class 11 students.

Learning outcomes

  • Understand the definition and causes of ocean waves.
  • Explain the origin and types of tides, including spring tides.
  • Identify the factors influencing the distance between the Earth and the Moon (perigee/apogee).
  • Describe how ocean currents affect global temperatures and climate.
  • Relate tidal movements to their impact on navigation and port accessibility.

Topics covered

Paper topics

  • Ocean Waves
  • Wave Energy
  • Tides
  • Spring Tides
  • Neap Tides
  • Perigee and Apogee
  • Perihelion and Aphelion
  • Ocean Currents
  • Effect of Currents on Temperature
  • Effect of Currents on Climate
  • Tides and Navigation
  • Port of Kolkata

Important topics

  • Causes and characteristics of waves
  • Tidal forces and their effects
  • Spring tides and neap tides
  • Perigee, Apogee, Perihelion, Aphelion
  • Influence of ocean currents on climate
  • Role of tides in navigation

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Questions and Solutions

Multiple choice question

1. Upward and downward movement of ocean water is known as the:
  1. tide
  2. current
  3. wave
  4. none of the above
Solution: The alternate rise and fall of the ocean surface is a characteristic phenomenon. This rhythmic vertical movement of seawater is defined as a tide. Currents refer to the horizontal movement of water, and waves are oscillatory movements caused by disturbances like wind. Therefore, the correct answer is (a) tide.

Multiple choice question

2. Spring tides are caused:
  1. As result of the moon and the sun pulling the earth gravitationally in the same direction.
  2. As result of the moon and the sun pulling the earth gravitationally in the opposite direction.
  3. Indention in the coast line.
  4. None of the above.
Solution: Spring tides occur when the Sun, the Moon, and the Earth are aligned in a straight line. During the new moon and full moon phases, the gravitational forces of both the Sun and the Moon act together in the same direction, resulting in exceptionally high high tides and very low low tides. This combined pull amplifies the tidal bulge. Therefore, the correct option is (a).

Multiple choice question

3. The distance between the earth and the moon is minimum when the moon is in:
  1. Aphelion
  2. Perigee
  3. Perihelion
  4. Apogee
Solution: The Moon's orbit around the Earth is elliptical, not perfectly circular. The point in its orbit where the Moon is closest to the Earth is called the perigee. Apogee is the opposite point, where the Moon is farthest from Earth. Aphelion and Perihelion refer to the Earth's distance from the Sun. Thus, the minimum distance between the Earth and the Moon occurs at perigee, making (b) the correct answer.

Multiple choice question

4. The earth reaches its perihelion in:
  1. October
  2. September
  3. July
  4. January
Solution: Perihelion is the point in Earth's orbit where it is closest to the Sun. This event typically occurs in early January each year, around January 3rd. Aphelion, when Earth is farthest from the Sun, occurs in early July. Therefore, the correct answer is (d) January.

Answer the following questions in about 30 words

(i) What are waves?
Solution: Ocean waves are essentially oscillatory movements observed on the surface of the sea or ocean. They are characterized by the alternate rise and fall of the water level, creating a rhythmic pattern of crests and troughs.

Answer the following questions in about 30 words

(ii) Where do waves in the ocean get their energy from?
Solution: The primary source of energy for ocean waves is the wind. As wind blows across the water surface, it transfers energy to the water, creating waves. The size and force of these waves are significantly influenced by three key factors: the velocity of the wind, the duration for which the wind blows, and the distance over which the wind can travel without obstruction.

Answer the following questions in about 30 words

(iii) What are tides?
Solution: Tides refer to the periodic rise and fall of the sea level that occurs, typically once or twice a day. This phenomenon is mainly caused by the gravitational forces exerted by the Moon and the Sun on the Earth's oceans, causing the water to bulge and recede.

Answer the following questions in about 30 words

(iv) How are tides caused?
Solution: Tides are primarily caused by the gravitational pull of the Moon and the Sun on the Earth's water bodies. Additionally, the centrifugal force, which arises from the Earth's rotation and acts in opposition to gravity, also contributes to the tidal forces that create the rise and fall of sea levels.

Answer the following questions in about 30 words

(v) How are tides related to navigation?
Solution: Tides play a vital role in navigation by influencing the depth of water in coastal areas and rivers. For instance, the Port of Kolkata, a significant riverine port located far from the sea, becomes accessible to ocean-going vessels due to the tidal nature of the Hooghly River's mouth, which allows for deeper drafts.

Answer the following questions in about 150 words

1. How do currents affect the temperature? How does it affect the temperature of coastal areas in the N. W. Europe?
Solution: Ocean currents have a profound impact on global temperatures. Warm currents flowing from tropical regions towards the poles carry heat, thereby raising the temperature of the ocean water and influencing the climate of adjacent coastal areas. Conversely, cold currents originating from polar regions and moving towards the equator bring cooler water, leading to a decrease in temperature. In the case of North-West Europe, the North Atlantic Drift, a warm current, significantly moderates the climate. Despite its high latitude, this region experiences milder winters and a more temperate climate than other areas at similar latitudes, largely due to the heat transported by this warm current. This results in a distinct marine climate, characterized by less extreme temperature variations compared to continental interiors.

Common mistakes

  • Confusing the terms aphelion/perihelion (Earth-Sun) with apogee/perigee (Earth-Moon).
  • Misunderstanding the gravitational forces causing spring tides (same direction vs. opposite).
  • Incomplete understanding of the factors determining wave size and energy.
  • Not clearly distinguishing between the causes of tides (gravity, centrifugal force).

Revision tips

  • Draw diagrams to visualize the positions of the Sun, Moon, and Earth during spring tides.
  • Create a table to compare and contrast waves, tides, and currents.
  • Focus on understanding the cause-and-effect relationships, such as wind on waves and gravity on tides.
  • Review the specific examples given for how currents affect climate, like in Europe.

Practice MCQs

Q1. What is the primary source of energy for ocean waves?

Q2. Spring tides occur when the Moon and the Sun pull the Earth gravitationally in the:

Q3. The point in the Moon's orbit where it is closest to the Earth is called:

Q4. Which of the following factors is NOT directly responsible for the size and force of waves?

Q5. How do warm ocean currents generally affect coastal areas?

Frequently asked questions

What are the main movements of ocean water discussed in this chapter?

This chapter discusses three main movements of ocean water: waves, tides, and currents. Waves are oscillatory movements on the surface, tides are the rise and fall of sea level, and currents are the continuous, directed movement of seawater.

What causes tides?

Tides are primarily caused by the gravitational pull of the Moon and the Sun on the Earth's oceans. The centrifugal force, acting to counter gravity, also plays a role.

How do ocean currents affect climate?

Ocean currents significantly affect climate by transferring heat. Warm currents raise the temperature of coastal areas, leading to warmer and potentially wetter climates, while cold currents lower temperatures.

What is the difference between perigee and apogee?

Perigee is the point in the Moon's orbit when it is closest to the Earth, while apogee is the point when it is farthest from the Earth.

How are tides important for navigation?

Tides are crucial for navigation as they can make rivers navigable for large vessels, even far inland. The Port of Kolkata, for example, relies on the tidal nature of the Hooghly River.

What factors determine the size of ocean waves?

The size and force of ocean waves are determined by the velocity of the wind, the duration for which the wind blows, and the distance over which the wind can blow unhindered.

Important links

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