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Chapter 13: Movements of Ocean Water MCQs

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Class 11 • Geography

Chapter 13: Movements Of Ocean Water

Source: NCERT Official Textbook

This chapter details the three fundamental movements within the world’s oceans: Waves, Tides, and Currents. It begins by explaining that Waves are essentially energy traveling through water, generated primarily by wind. As waves approach shore, friction with the seafloor causes them to slow down and eventually break. Key wave characteristics like crest, trough, wavelength, and period are defined.

The second major movement is Tides, the periodic rise and fall of sea level caused primarily by the gravitational attraction of the moon and, to a lesser extent, the sun, combined with centrifugal force. This creates two tidal bulges on Earth.

The chapter classifies tides by frequency (semi-diurnal, diurnal, mixed) and by the sun-moon-earth alignment (Spring Tides during new/full moon and Neap Tides when the sun and moon are at right angles). It highlights the importance of tides for navigation, fishing, desilting estuaries, and generating tidal power.

Finally, the chapter covers Ocean Currents, the steady, river-like flows of water. Their movement is initiated by primary forces: solar heating, wind, gravity, and the Coriolis force (which creates large circular Gyres).

Currents are classified by depth (surface vs. deep water) and temperature (warm vs. cold). The distribution of major currents corresponds to global wind patterns.

The chapter concludes by explaining the significant effects of currents on coastal climates—cooling west coasts in the tropics and warming east coasts in higher latitudes—and their role in creating fertile fishing grounds where warm and cold currents mix.

Topics Covered:

Section A: Descriptive Questions

  1. What are the three types of movements in ocean water? Briefly define each. (Pg. 1) Page 108
  2. Explain how energy, not the water itself, moves across the ocean surface in the form of waves. (Pg. 1) Page 108
  3. Define the following characteristics of a wave: crest, trough, wavelength, and wave period. (Pg. 2) Page 109
  4. What causes tides? Explain the role of gravitational pull and centrifugal force in creating the two major tidal bulges. (Pg. 2) Page 109
  5. Differentiate between Spring Tides and Neap Tides based on the positions of the sun, moon, and earth. (Pg. 3) Page 110
  6. List the various importance of tides. (Pg. 3-4) Page 110-111
  7. How do differences in water density (salinity and temperature) affect the vertical mobility of ocean currents? (Pg. 4) Page 111
  8. How do ocean currents influence the climate of coastal regions? Provide examples based on latitude. (Pg. 5) Page 112

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Section B1: Objective MCQs

Page 108

Which movement of ocean water refers to the continuous flow of a huge amount of water in a definite direction? (Pg. 1)

A) WavesB) TidesC) Ocean CurrentsD) Surges
View Answer
Correct Answer: C
Reference: NCERT Page 108
Page 108

What is the primary source of energy for waves? (Pg. 1)

A) Tidal forcesB) Solar heatingC) WindD) Earth’s rotation
View Answer
Correct Answer: C
Reference: NCERT Page 108
Page 109

The horizontal distance between two successive wave crests is called: (Pg. 2)

A) Wave HeightB) Wave AmplitudeC) WavelengthD) Wave Frequency
View Answer
Correct Answer: C
Reference: NCERT Page 109
Page 109

The ‘tide-generating’ force is the difference between: (Pg. 2)

A) Solar and Lunar gravityB) Earth’s gravity and centrifugal forceC) Gravitational attraction of the moon and centrifugal forceD) Wind stress and Coriolis force
View Answer
Correct Answer: C
Reference: NCERT Page 109
Page 110

Which bay is famous for having the highest tides in the world? (Pg. 3)

A) Bay of BengalB) Hudson BayC) Bay of FundyD) Gulf of Mexico
View Answer
Correct Answer: C
Reference: NCERT Page 110
Page 110

Spring tides occur: (Pg. 3)

A) When the sun and moon are at right anglesB) When the moon is at apogeeC) When the sun, moon, and earth are in a straight lineD) Only during a lunar eclipse
View Answer
Correct Answer: C
Reference: NCERT Page 110
Page 111

What are the primary forces that initiate the movement of ocean currents? (Pg. 4)

A) Heating by solar energy, wind, gravity, Coriolis forceB) Centrifugal force and gravitational pullC) Earth’s rotation and magnetismD) Monsoon winds and pressure gradients
View Answer
Correct Answer: A
Reference: NCERT Page 111
Page 111

Which type of current brings cold water into warm water areas and is usually found on the west coast of continents in low/middle latitudes? (Pg. 4)

A) Warm CurrentB) Deep Water CurrentC) Surface CurrentD) Cold Current
View Answer
Correct Answer: D
Reference: NCERT Page 111
Page 112

The mixing zones of warm and cold currents are favourable for the growth of planktons because they help to: (Pg. 5)

A) Increase salinityB) Replenish oxygenC) Decrease temperatureD) Create gyres
View Answer
Correct Answer: B
Reference: NCERT Page 112
Page 113

(Exercise) Upward and downward movement of ocean water is known as the: (Pg. 6)

A) tideB) currentC) waveD) none of the above
View Answer
Correct Answer: A
Reference: NCERT Page 113
Page 113

(Exercise) Spring tides are caused: (Pg. 6)

A) As result of the moon and sun pulling earth in the same directionB) As result of the moon and sun pulling earth in opposite directionsC) Indention in the coast lineD) None of the above
View Answer
Correct Answer: A
Reference: NCERT Page 113
Page 113

(Exercise) The distance between earth and moon is minimum when the moon is in: (Pg. 6)

A) AphelionB) PerigeeC) PerihelionD) Apogee
View Answer
Correct Answer: B
Reference: NCERT Page 113
Page 113

(Exercise) The earth reaches its perihelion in: (Pg. 6)

A) OctoberB) SeptemberC) JulyD) January
View Answer
Correct Answer: D
Reference: NCERT Page 113

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Section B2: Factual One-Liners

The vertical motion of ocean water that refers to the rise and fall of sea level is called ______. (Pg. 1) Page 108

Reveal Answer
tides (Page 108)

When a wave approaches the beach, it slows down due to friction with the ______. (Pg. 1) Page 108

Reveal Answer
sea floor (Page 108)

Wave ______ is one-half of the wave height. (Pg. 2) Page 109

Reveal Answer
amplitude (Page 109)

The study of tides is complex due to great variations in frequency, magnitude, and ______. (Pg. 2) Page 109

Reveal Answer
height (Page 109)

Tides with two high and two low tides each day, with successive highs/lows of similar height, are called ______ tides. (Pg. 3) Page 110

Reveal Answer
semi-diurnal (Page 110)

The time between low tide and high tide, when the water level is rising, is called the ______. (Pg. 3) Page 110

Reveal Answer
flow or flood (Page 110)

Large circular currents in ocean basins caused by the accumulation of water and the Coriolis force are called ______. (Pg. 4) Page 111

Reveal Answer
gyres (Page 111)

The speed of a current is referred to as its ______. (Pg. 4) Page 111

Reveal Answer
drift (Page 111)

The major ocean currents are greatly influenced by the stresses exerted by the prevailing winds and the ______ force. (Pg. 5) Page 112

Reveal Answer
Coriolis (Page 112)

(Exercise) Waves in the ocean get their energy from ______. (Pg. 6) Page 113

Reveal Answer
wind (Page 113)

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