Oceanography MCQ Quiz - Objective Question with Answer for Oceanography - Download Free PDF

The correct answer is Warm Current.

Key Points

• Warm oceanic current is generally formed in the equatorial and tropical regions.
• Warm currents generally flow from lower latitudes towards higher latitudes.
• While Cold currents flow from higher latitudes towards lower latitudes.
• In the region where warm oceanic currents flow, humid climatic conditions are formed and in the regions where cold oceanic currents flow, arid climatic conditions are formed.
• Due to cold oceanic currents deserts are formed.
• In the regions where warm and cold oceanic currents meet, nutrients are found which increase the growth rate of phytoplankton.

Additional Information

Nature of Some important Oceanic currents:

Submarine Ridge.Key Points

• Mid-Oceanic Ridges or Submarine Ridges
  • A mid-oceanic ridge is composed of two chains of mountains separated by a large depression. [Divergent Boundary]
  • The mountain ranges can have peaks as high as 2,500 m and some even reach above the ocean’s surface.
  • Running for a total length of 75,000 km, these ridges form the largest mountain systems on earth.
  • These ridges are either broad, like a plateau, gently sloping or in the form of steep-sided narrow mountains.
  • These oceanic ridge systems are of tectonic origin and provide evidence in support of the theory of Plate Tectonics.
  • Iceland, a part of the Mid-Atlantic Ridge, is an example.

The correct answer is seven.

Key Points

• There is a seven-day interval between the spring tides and neap tides.
• Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth.
• There are two types of tides namely, spring tides and neap tides depending upon the relative positions of the sun, the earth, and the moon.
• Spring tides:
  • When the sun, the moon, and the earth are in a straight line, the height of the tide will be higher.
  • These are called spring tides and they occur twice a month, one during the full moon period and another during the new moon period.
• Neap tides:
  • Normally, there is a seven-day interval between the spring tides and neap tides.
  • At this time the sun and moon are at right angles to each other and the forces of the sun and moon tend to counteract one another.
  • The Moon's attraction, though more than twice as strong as the sun's, is diminished by the counteracting force of the sun's gravitational pull.
  • Like spring tides, these tides also occur twice a month.

The correct answer is 3 only.

Key Points

• West Wind Drift is a cold ocean current that flows in the Southern Hemisphere and is also known as the Antarctic Circumpolar Current.
• The current is driven by the strong westerly winds, moving from west to east around Antarctica.
• It plays a crucial role in regulating the global climate by facilitating the exchange of heat and nutrients between the world's oceans.
• Alaska Current and North Atlantic Drift are warm currents, not cold currents, and flow in the Northern Hemisphere.

Additional Information

• Ocean Currents:
  • Ocean currents are continuous, directed movements of seawater generated by forces such as wind, the Coriolis effect, and temperature/salinity differences.
  • They are categorized into warm and cold currents depending on their temperature relative to the surrounding water.
• Warm Currents: These currents, such as the North Atlantic Drift and Alaska Current, originate near the equator and transport warm water to higher latitudes.
• Cold Currents: These currents, like the West Wind Drift and Labrador Current, transport cold water from polar areas to lower latitudes.
• Antarctic Circumpolar Current: This is the largest ocean current in the world, connecting the Atlantic, Pacific, and Indian Oceans and playing a key role in the global conveyor belt of ocean circulation.
• Impact of Ocean Currents: They influence global climate patterns, marine biodiversity, and even human activities such as fishing and shipping.

The correct answer is option 3.

Key Points

• An Atoll is a ring-shaped coral reef, island, or series of islets surrounding a lagoon. Hence, option 3 is correct.
• Atolls are typically formed from the subsidence of volcanic islands surrounded by coral reefs, which continue to grow upward as the island sinks.
• This results in a circular or horse-shoe shaped reef enclosing a central lagoon.

The correct answer is The US.

• The Grand Canyon is an example of a valley that is an erosional landform.
  • Erosion - It is the geological process in which earthen materials such as soil or rock are removed and transported by natural forces such as wind or water.
    • Valleys start as small and narrow rills.
    • The rills will gradually develop into long and wide Gullies.
      • A rill means a small stream.

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• The gullies will further deepen, widen, and lengthen to give rise to valleys.
  • Gully - A small passage formed due to stream.

• Depending upon dimensions and shape, many types of valleys like V-shaped valleys, gorge, canyon, etc. can be recognised.
  • V-shaped valley 

• A canyon is characterised by steep steplike side slopes.
• A canyon is wider at its top than at its bottom. In fact, a canyon is a variant of a gorge.
• Valley types depend upon the type and structure of rocks in which they form.
  • Example - canyons commonly form in horizontal bedded sedimentary rocks and gorges form in hard rocks.
• The Grand Canyon :

• Gorge - A narrow valley with steep sides and a river running through it.

The correct answer is the Atlantic ocean.

Key Points

Atlantic Ocean:

• The ocean that forms the shape of the letter “S”, is the Atlantic ocean if it is looked closely on the world map.
• The Arctic Ocean is connected/ linked through the  Barents Sea, Norwegian Sea, Greenland Sea, and the Denmark Strait.
• The Puerto Rico Trench, which is about  28,230 feet deep, is the deepest point in the Atlantic Ocean.
• It is also the busiest ocean in terms of Commerce and Trade

Additional Information

Pacific Ocean:

• It is the largest and deepest ocean on Earth.
• The Extension of this ocean is from the Arctic Ocean in the north to the Southern Ocean in the south.
• This ocean is also bounded by the continents of Asia, Australia, and the Americas.
• The Challenger Deep depth of 10,902 to 10,929 m, lies in the Mariana Trench, which is the deepest point in the world located in this ocean.

Mediterranean:

• The sea was an important and famous route for merchants and travellers of ancient times.
• It also facilitated trade and cultural exchange between peoples of the region and around the world.
• The Strait of Gibraltar connects the Atlantic Ocean to the Mediterranean Sea and it also separates Spain in Europe from Morocco in Africa.

Indian Ocean:

• It is the third-largest of the world's oceans on Earth's surface.
• It is bounded by Asia, Africa and Australia to the north, west and east respectively.
• The Southern Ocean or Antarctica bounds it to the south.
• The Indian Ocean has some regional seas such as the Arabian Sea, Bay of Bengal, the Laccadive Sea, the Somali Sea, and the Andaman Sea.

The Correct Answer is Kuroshio Current.

Important Points

• Kuroshio Current:
  • It is also known as Japan Current and flows from Taiwan to the Bering Strait.
  • It is a warm current of the Pacific Ocean.
• Humboldt Current:
  • It is a Cold current of the Pacific Ocean.
  • Flows northwards along the western coast of South America and is actually the continuation of west wind drift.
• Labrador Current:
  • It is a Cold current of the Atlantic Ocean.
  • It Originates in the Baffin Bay drifts south eastwards Baffin and Greenland and merges with the Gulf Stream of New Foundland.
• Canaries Current:
  • It is a cold current of the Atlantic Ocean.
  • It is the continuation of North Atlantic Drift along the western coast of the Iberian Peninsula and North Africa in the southern direction .

The correct answer is Tide.

Key Points

• The rhythmic rise and fall of the ocean twice a day is called a tide.
• The intense gravitational force exerted by the sun and the moon on the surface of the earth induce tides.

Additional Information

• When water covers most of the shore by rising to its maximum level, it is known as high tide.
• It is low tide as the waterfalls to its lowest level and recedes from the sea.
• The water of Earth closer to the moon is drawn under the influence of the gravitational force of the moon which creates a high tide.
• The sun, the moon, and the earth are in the same line during the full moon and new moon days and the tides are highest. These tides are called the spring tides.
• But when the moon is in its first and last quarter, the ocean waters are drawn in diagonally opposite directions through the gravitational force of the sun and earth resulting in low tides. These tides are called neap tides.
• High tides help in navigation as they raise the level of water closer to the coast. This makes it easier for ships to enter the harbour.
• High tides assist with fishing as well as much more fish, move closer to the sea during the high tide. This helps fishermen to have an abundant harvest.
• The rise and fall of water due to tides is being used in some places to generate electricity.

Earth's Tides

The correct answer is Option 4 i.e. Falkland Current.

The Atlantic Ocean is divided into two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) the Atlantic Ocean at about 8°N

Ocean currents in the Atlantic Ocean include the below-given currents:

• Gulf stream:
• Another part of the Cayenne current heads northwards east of the Antilles as the Gulf Stream.
• The Gulf stream is one of the strongest ocean currents.

Hence, option 4 is the correct answer.

Mistake Points

Labrador Current:

The correct answer is Indian.

Important Points

• Madagascar is an island country in the Indian Ocean.
• Madagascar is the largest African island situated in the Indian Ocean, about 450 km (280 mi) east of the coast of Mozambique.
• The fourth-largest island in the world has been isolated for about 88 million years and many of its plants and animals are unique to the island.
• Madagascar consists of three parallel longitudinal zones, the central plateau, the coastal strip in the east, and the zone of low plateaus and plains in the west.

Additional Information

• Greenland located near North America is the largest island in the world. 

• The Great Nicobar Island is the largest island in India. It is the southernmost point of India.
• A group of islands is termed as archipelago.

The correct answer is Agulhas current.

• The Agulhas Current is the western boundary current of the South Indian Ocean.
• It flows down the east coast of Africa from 27°S to 40°S.

Important Points

• Currents in the Indian Ocean include the following:
  • The North-East Monsoon Drift
  • The South West Monsoon Drift
  • North Equatorial Current (Warm)
  • South Equatorial Current (Warm)
  • Somali Current (Cold)
  • Mozambique Current (Warm)
  • Madagascar Current (Warm)
  • Agulhas Current (Warm)
  • West Australian Current (Cold)

Additional Information

• The Florida Current is a thermal ocean current that flows from the Straits of Florida around the Florida Peninsula and along the southeastern coast of the United States.
• Canary Current, part of a clockwise-setting ocean-current system in the North Atlantic Ocean.
• Oyashio Current or the Kurile current is the western boundary current in the subpolar gyre of the North Pacific.
• It originates in the Bering Sea and flows south-west off the Kuril Islands to meet the Kuroshio Current east of northern Japan.

The correct answer is Pacific.

Key Points

• Many volcanic eruptions and earthquakes occur in the Ring of Fire, which runs along much of the Pacific Ocean's rim.
• The Ring of Fire is a 40,000 km long and up to 500 km broad horseshoe-shaped ring.
• The Pacific coasts of South America, North America, and Kamchatka, as well as certain islands in the western Pacific Ocean, make up the Ring of Fire.
• Although geologists agree on almost all of the locations that make up the Ring of Fire, the dispute on the inclusion or exclusion of a few areas, such as the Antarctic Peninsula and western Indonesia.
• Plate tectonics, specifically the movement, collision, and destruction of lithospheric plates beneath and around the Pacific Ocean, has created the Ring of Fire.
• There is no single geological feature that makes up the Ring of Fire. Each segment of the Ring of Fire experiences volcanic eruptions and earthquakes independently of eruptions and earthquakes in other parts of the Ring.

Important Points

• The Pacific Ocean is the world's largest and deepest oceanic division.
• It stretches from the Arctic Ocean to the Southern Ocean in the south and is bordered on the west by Asia and Australia, and on the east by the Americas.
• With a surface area of 70,560,000 km², the Indian Ocean is the third largest of the world's five oceanic divisions. Asia to the north, Africa to the west, and Australia to the east define its borders.
• The Atlantic Ocean is the world's second-largest ocean, covering approximately 106,460,000 km².
• Of the world's five major oceans, the Arctic Ocean is the smallest and shallowest. It is the coldest of all the seas, covering an area of approximately 14,060,000 km².

Tsunami is a Japanese word with the English translation, "harbour wave."

Key Points:

Represented by two characters, the top character, "tsu," means harbor, while the bottom character, "nami," means "wave."

In the past, tsunamis were sometimes referred to as "tidal waves" by the general public, and as "seismic sea waves" by the scientific community.

The term "tidal wave" is a misnomer; although a tsunami's impact upon a coastline is dependent upon the tidal level at the time a tsunami strikes, tsunamis are unrelated to the tides.

Tides result from the imbalanced, extraterrestrial, gravitational influences of the moon, sun, and planets. The term "seismic sea wave" is also misleading. "Seismic" implies an earthquake-related generation mechanism, but a tsunami can also be caused by a nonseismic event, such as a landslide or meteorite impact.

Causes a Tsunami

• Subduction Zones are Potential Tsunami Locations
• Most tsunamis are caused by earthquakes generated in a subduction zone, an area where an oceanic plate is being forced down into the mantle by plate tectonic forces. The friction between the subducting plate and the overriding plate is enormous. This friction prevents a slow and steady rate of subduction and instead the two plates become "stuck."
• Accumulated Seismic Energy
• As the stuck plate continues to descend into the mantle, the motion causes a slow distortion of the overriding plate. The result is an accumulation of energy very similar to the energy stored in a compressed spring. Energy can accumulate in the overriding plate over a long period of time - decades or even centuries.
• Earthquake Causes Tsunami
• Energy accumulates in the overriding plate until it exceeds the frictional forces between the two stuck plates. When this happens, the overriding plate snaps back into an unrestrained position. This sudden motion is the cause of the tsunami - because it gives an enormous shove to the overlying water. At the same time, inland areas of the overriding plate are suddenly lowered.

The correct answer is seven.

Key Points

• There is a seven-day interval between the spring tides and neap tides.
• Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth.
• There are two types of tides namely, spring tides and neap tides depending upon the relative positions of the sun, the earth, and the moon.
• Spring tides:
  • When the sun, the moon, and the earth are in a straight line, the height of the tide will be higher.
  • These are called spring tides and they occur twice a month, one during the full moon period and another during the new moon period.
• Neap tides:
  • Normally, there is a seven-day interval between the spring tides and neap tides.
  • At this time the sun and moon are at right angles to each other and the forces of the sun and moon tend to counteract one another.
  • The Moon's attraction, though more than twice as strong as the sun's, is diminished by the counteracting force of the sun's gravitational pull.
  • Like spring tides, these tides also occur twice a month.