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Oceanography — UPSC Prelims Geography previous year questions — page 2

121 solved previous year questions on Oceanography, papers from 1992 to 2022, drawn from UPSC CSE Prelims, UPSC CDS, UPSC CAPF. Each carries the printed answer key and the explanation from the source compilation.

1. #41Practice set
   Consider the following statements regarding the Sea floor spreading: 1. The age of rock increases as one moves away from the centre of mid oceanic ridge. 2. The deep trenches have deep-seated earthquakes while in the mid-oceanic ridge areas, the quake foci usually have shallow depths.Which of the statements given above is/are correct?
   • A1 only
   • B2 only
   • CBoth 1 and 2
   • DNeither 1 nor 2
   Answer: (C) Both 1 and 2
   Explanation

   Option c is the correct l is correct. The newest, thinnest crust on located near the centre of mid-ocean ridge-the of seafloor spreading. The age, density, and thickness crust increases with distance from the 2 is correct. The mid oceanic ridges are frequent shallow earthquakes due to up thrust of the at the convergent plate boundaries, deep are found. Therefore at deep trenches earthquakes are found

2. #42Practice set
   Which of the following is/are the evidence of sea floor spreading? 1. The rocks on either side of the mid oceanic ridges show similarities in terms of magnetic properties. 2. The ocean crust rocks are much younger than the continental rocks. 3. The temperature near the mid-oceanic ridge is warmer as compared to other surfaces away from the ridge.Select the correct answer from the code given below
   • A1 and 2 only
   • B2 and 3 only
   • C1 and 3 only
   • D1, 2 and 3
   Answer: (D) 1, 2 and 3
   Explanation

   Option d is the correct spreading is a geologic process where there is addition of new oceanic crust in the ocean volcanic activity while moving the older from the mid-oceanic ridge. Seafloor spreading by an American geophysicist, Harry H. Hess when he provided evidences in support of l is correct: Particularly, the mapping of the and palaeomagnetic studies of rocks from revealed the following facts: The rocks either side of the crest of mid-oceanic ridges similarities in terms of the period of compositions, and magnetic properties. to the mid-oceanic ridges have normal polarity the youngest. The age of the rocks increases as one from the crest. This records that there is a and spreading of rocks on the ocean 2 is correct: The ocean crust rocks are than the continental rocks. The age of rocks in crust is nowhere more than 200 million years of the continental rock formations are as old as

3. #43Practice set
   Consider the following stat em en ts regarding the terms related with Groundwater: 1. Vadose zone is an unsaturated zone of soil where water is totally absent. 2. Phreatic zone is the zone where the crustal pores and fractures are saturated with water. 3. The Groundwater table marks the upper limit of the zone of saturation.How many of the statements given above are correct?
   • AOnly one
   • BOnly two
   • CAll three
   • DNone
   Answer: (B) Only two
   Explanation

   Option b is the correct l is incorrect: Water percolates from the zone through the unsaturated zone to the This Unsaturated zone is called as Vadose vadose zone the pores contain some air. The water in the zone. The zone is situated at shallow is above the water 2 is correct: The phreatic zone is situated water table, in which relatively all pores and saturated with water. The phreatic zone size, color, may fluctuate with changes of season, and during dry periods. Statement 3 is correct: At the boundary between and Phreatic zone is the groundwater table, water table. The water table is a surface that upper limit of the zone of saturation

4. #44Practice set
   Which of the following is the correct statements regarding the significance of presence of bars, barriers and beaches? 1. Off-shore bars provides defense against storm and tsunami by absorbing most of their destructive force. 2. Barrier islands offer an important habitat for a wide variety of fish, shellfish, sea bird and sea turtle species. 3. Beaches help to protect the coastal structures by creating enough space for the ocean current energy to dissipate.Select the correct answer using the codes given below
   • A1 only
   • B2 and 3 only
   • C1 and 3 only
   • D1, 2 and 3
   Answer: (D) 1, 2 and 3
   Explanation

   Option d is the correct answer. Hi'. l is correct: A ridge of sand and shingle the sea in the off-shore zone (from the position of waterline to seaward) lying approximately parallel to is called an off-shore bar. The coastal off-shore the first buffer or defence against storm or absorbing most of their destructive 2 is correct: Barrier islands are a type of up of long stretches of sand that are parallel to Barrier islands offer an important habitat wide variety of fish, shellfish, sea bird and sea The ecosystems which develop around are unique in many respects. Sea turtles, for the ocean-facing beaches of barrier islands to 3 is correct: Beaches are characteristic that are dominated by deposition, but may patches along even the rugged shores. Beaches assist protection of coastal structures from destruction The beach also protects the upland structures storm bars, which prevent storms fro

5. #45Practice set
   Which of the following is incorrect with respect to the Ekman Spiral?
   • AIt is a combined result of the friction force of wind and Coriolis force on the ocean water
   • BIt ceases to operate in ocean water at depths of more than 100 metres
   • CIt has reduced action of wind with increasing depth of ocean water
   • DIt necessarily results in the increased biological activity in the area of its occurrence
   Answer: (D) It necessarily results in the increased biological activity in the area of its occurrence
   Explanation

   Option d is the correct Ekman spiral is named after Swedish sdf'ntist (1874-1954) who first theorised it in a is correct: Ekman spirnl is a consequence of friction force of wind and coriolis force on ocean when ocean surface waters are influenced by force acting on them via the wind. However, due influence of the Coriolis effect, the ocean water moves angle from the direction of the surface b is correct: Each layer of water molecules by friction from the shallower layer, and each moves more slowly than the layer above it, until ceases at a depth of about l 00 metres (330 c is correct: When surface water molecules are the wind, they drag deeper layers of water them. Like surface water, the deeper water by the Coriolis effect-to the right in the and to the left in the Southern Hemisphere. As each successively deeper layer of water moves lo the righl or left, creating u spiral effect. Thus

6. #46Practice set
   Which of the following situations would most likely result in the formation of a 'Lagoon'?
   • ASedimentary beds of rivers/streams become gentler due to continued erosion
   • BA River shifts laterally making a series of natural levees
   • CBarrier bars and spits are formed at the mouth of a bay and they block it
   • DWaters spill over the banks during flooding above the river bed
   Answer: (C) Barrier bars and spits are formed at the mouth of a bay and they block it
   Explanation

   Option c is the correct lagoon is a shallow body of water protected from a of water ( usually the ocean) by sandbars, barrier islands, coral reefs. It is an elongated narrow saline -- water provides security to coast which is associated with the after its formation. Such lakes which are found at of bars and beaches are known as barrier bars and spits form at the mouth of a block it, a lagoon forms. The lagoons would filled up by sediments from the land giving rise to plain

7. #47Practice set
   What is the difference between an Alluvial plain and an Outwash Plain? 1. Outwash plains are located on the floor of the ocean, whereas Alluvial plains are glacial sediments deposited on land surface. 2. Unlike Outwash plains, Alluvial plains are usually fertile due to its loamy texture.Select the correct answer using the codes given below
   • A1 only
   • B2 only
   • CBoth 1 and 2
   • DNeither 1 nor 2
   Answer: (B) 2 only
   Explanation

   Option b is the correct I is incorrect: An outwash plain is a by the sedimentary deposits by a glacier when while the alluvial plains are caused by the is caused by the water currents in the seas, river or 2 is correct: Alluvial plains are the most because it has a loamy texture (contain sand, slit) and is rich in humus, contains organic plains are infertile. It consists of gravel, silt, clay

8. #48Practice set
   Fjord is a glacial landform. Regarding Fjord, consider the following statements. L A fjord is formed when a glacier retreats after carving its typical U-shaped valley, and then the sea fills the resulting valley floor with water. 2. Fjords are characteristically very shallow and wide water bodies. ok GWhich of the statements given above is/are correct?
   • A1 only
   • B2 only
   • CBoth 1 and 2
   • DNeither 1 nor 2
   Answer: (A) 1 only
   Explanation

   Option a is the correct word fjord was mostly used in the meaning "where through", which has the same origin as the word It is a landform of highland 1 is correct: A fjord is formed when a after carving ils typical U-shaped valley, and the the resulting valley floor. The fjords were thus formed giant glacier tongues that through several ice ages the 2 is incorrect: A fjord is a deep, narrow sea or lake drain, with steep land on three opening toward the sea is called the mouth of the is often shallow. The fjord's inner part is called the Tf formation is wider than it is long, not a fjord. Then it is a bay or cove

9. #49Practice set
   With reference to various coastal landforms, consider the following statements: 1. A Tombolo is formed when a 'Spit' connects the mainland coast to an island. 2. A Gloup is a steep and often vertical column of rock in the sea near a coast.Which of the statements given above is/ are correct?
   • A1 only
   • B2 only
   • CBoth 1 and 2
   • DNeither 1 nor 2
   Answer: (A) 1 only
   Explanation

   Option a is the correct l is correct: A Tombolo is formed when connects the mainland coast to an island. A spit feature that is formed through deposition of material The process of longshore drift occurs, and material along the coastline. (Fig. below is 2 is incorrect: Gloup is an opening in the a sea cave through which incoming waves may force air upward or water to spout intermittently. Important Tips Stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion. Stacks are formed over time by wind and water, processes of coastal geomorphology. Like all other features, sea stacks are also temporary and eventually coastal hills and cliffs will disappear because of wave erosion giving rise to narrow coastal plains

10. #50Practice set
    What is common among Ria coasts, Dalmitian coast and Fiord coast?
    • AThey all have Submergent coastline
    • BThey all have Emergent coastline
    • CThey all have Concordant coastline
    • DThey all have Discordant coastline. Practice
    Answer: (A) They all have Submergent coastline
    Explanation

    Option a is the correct is the area where land meets water. The an endless supply of waves, whether pounding or is constantly changing coastlines around the coastlines are coastlines submerged due to rising sea levels. Many of these types were actually formed toward the end of the Period (LGP). Such coasts are Ria coasts, Dalmatian Coast and Estuarine coasts. Important Tips Emergent coastlines happen when either the water level has fallen, or the land has risen. Emergent coastlines can pop up after tectonic activity. Emergent c Jastlines can have features such as marine terraces, relict sea cliffs, sea stacks, and raised Discordant coastlines occur when bands of different types of rocks run perpendicular (at 90 degrees) to the coast. Concordant coastlines have bands of similar rock types running parallel (alongside) to the coast. The difference in rock types between discordant and concor

11. #51Practice set
    The Subsidence Theory and the Glacial Control Theory are related to
    • AFormation of mantle plume
    • BFormation of coral reefs and atolls
    • CChronological sequencing of fossils
    • DDirection of Gyre circulations book G
    Answer: (B) Formation of coral reefs and atolls
    Explanation

    Option b is the correct theory and Glacial control theory are the formation of coral reefs and atolls. The was postulated by Charles Darwin in 1837 in 1842. According to this theory, fringing APHY barrier reefs, and atolls are successive stages of coral due to the gradual subsidence of land. theory was proposed by Reginald Aldworth to this theory, fluctuations of sea level building up and melting down of glaciers during Epoch played a major role in allowing coral build up structures

12. #52Practice set
    W'ith reference to different types of coasts, consider the following statements: 1. Ria coasts are formed due to upliftment of continental self. 2. Fjord coasts are the result of drowned glaciated valleys. 3. Dalmatian coasts are longitudinal coasts where mountains run parallel to the coast.How many of the above statements are correct?
    • AOnly one
    • BOnly two
    • CAll three
    • DNone
    Answer: (B) Only two
    Explanation

    Option b is the correct 1 is incorrect. Ria Coasts are drowned Ria coast is a coastal inlet formed by the of an ungladated river valley that to the sea is a coastline having several parallel by prominent ridges, extending a distance 2 is correct. Fjord coasts are drowned which were created by glaciers that moved over time, and greatly altered the landscape moved through an area carving deep valley. Fjord formed when a glacier retreats, after carving its valley with the sea filling the resulting valley flo Statement 3 is correct. Dalmatian coasts are a where the mountains run parallel to the coast, submergence of the coastline produces long, with a chain of islands parallel to the coast. Here islands are the crests of former ranges inlets were the former longitudinal valleys. 'cigas

13. #53Practice set
    Consider the following statements: 1. Antarctic glaciers terminate in the sea as floating ice shelves. 2. Antarctic glaciers are not affected by ocean currents. 3. Antarctic region experiences some warming due to tropospheric westerlies.How many of the above statements are correct?
    • AOnly one
    • BOnly two
    • CAll three
    • DNone
    Answer: (B) Only two
    Explanation

    Option b is the correct is the world's largest ice sheet. Much of ice sheet surface lies above m above sea massive thickness of ice drowns whole mountain numerous volcanoes exist underneath the icey l is correct. The Antarctic Ice Sheet is drained ice streams, which respond quickly to they can thin, accelerate, recede, or even stop Beneath the thick skin of ice, there is flowing subglacial glaciers terminate on land or in the sea, ice shelves or grounded or floating outlet 2 is incorrect. Antarctica is affected by Parts of West Antarctica are grounded well level, which can act to destablise the ice sheet. currents are able to melt ice shelves from below, a retreat of the glaciers. The Antarctic (ACC) is an ocean current that flows clockwise to east around 3 is correct. arming over the is exacerbated by a strengthening of the which is a periodic strengthening and the tropospheri,; westerl

14. #54Practice set
    In context of World Geography, Consider the following statements about Emergent coasts: 1. These coasts are formed due to tectonic uplift of the land surface or a fall in the elevation of sea level. 2, Ria and fjord coasts are the example of emergent coast.Which of the statements given above is/are correct?
    • A1 only
    • B2 only
    • CBoth 1 and 2
    • DNeither 1 nor 2
    Answer: (A) 1 only
    Explanation

    Option a is the correct characteristics of a coast depend on its initial topographic configuration, and that shape it. A drop in sea level or rise in the creates an emergent coast. I is correct: Emergent coasts are a result of uplift of the land surface or a fall in the sea level because of a reduction in the water volume basins. Often, emergent coasts have rocky cliffs and nearly flat platforms. very good an emergent coastline is the west coast of North of the Scandinavian coastline (Sweden and also emergent 2 is incorrect: Ria and fjord coasts are of submergent coast. Ria coasts are formed due of river valleys whereas fjord coasts are to submergence of glaciated valleys

15. #55Practice set
    With reference to formation of different types of Coasts, consider the following statements: 1. Ria coasts are formed by the submergence of river valleys emptying into the ocean. 2. Fjord coasts are formed when waves create troughs in areas having limestone rocks. 3. Barrier Island coastsare formed by deposits of sand separated from land by a lagoon.How many of the statements given above are correct?
    • AOnly one
    • BOnly two
    • CAll three
    • DNone
    Answer: (B) Only two
    Explanation

    Option bis the correct are the dynamic junction of water, air, and and waves, tides and currents, migrating sand mud flats, a variety of plant and animal life, all form ever-changing I is correct: Ria coasts are formed by of river valleys emptying into the of Ria coasts are found in New England and coast of Europe, especially 2 is incorrect: Fjord (fiord) coasts are glacial troughs are flooded due to a rise in sea coasts are deeply indented, with steep-walled beaches are rare as sediment eroded from valley on the floor. Fjords are common in Columbia, Alaska, and 3 is correct: Barrier Island coasts are by deposits of sand separated from land by They begin as offshore bars of submerged migra,te landward unless stabilized. Barrier islands cut by tidal inlets, openings that allow water to and seaward with the tides. Barrier islands Atlantic coastal plain of North America. Important Tips The

16. #56Practice set
    With reference to the upwelling and downwelling process of the ocean water, consider the following statements: 1. Upwelling of an ocean occurs when the wind blows towards the shore. 2. Downwelling of an ocean occurs in the divergence zone of ocean water. 3. Upwelling region offers one of the best fishing grounds across the world. 4. Fogs near the coastal area are a likely indicator of an upwelling zone.How many of the statements given above are correct?
    • AOnly one
    • BOnly two
    • COnly three
    • DAll four
    Answer: (B) Only two
    Explanation

    Option bis the correct I is incorrect: The winds blowing from the the oceans drive warm surface water away from resulting in the Upwelling of ocean. Water then rises the water that was pushed away, and this process as 2 is incorrect: Downwelling occurs in zone of ocean water and upwelling in zone. Downwelling occurs when wind the shore and causes surface water to build a coastline. During this process, the surface sinks toward the bottom. This water will and poor in 3 is correct: Subsurface water that rises to as a result of upwelling is typically colder, nutrients, and biologically productive. Good typically are found where is common. Statement 4 is correct: During upwelling the water that replace the water that has heen pushed away is This will lead to fog near coaslal zones. For in the San Francisco area contributing to summer fogs

17. #57Practice set
    Consider the following pairs:Ocean Features topography 1. Mid oceanic Zone of intense volcanic ridges activity 2. Sea mounts Zone of low biological productivity 3. Submarine Deep valleys in the __ ca_l'lyons continental shelves 4. Guyots Mountain in ocean with pointed summitsHow many of the pairs given above are correctly matched?
    • AOnly one
    • BOnly two
    • COnly three
    • DAll four
    Answer: (B) Only two
    Explanation

    Option b is the correct 1 is correct: The Mid Ocean Ridges exist in the the ocean basins, where the divergent plate located. These zones are tectonically active regions, are the most active volcanic regions on the 2 is incorrect: Seamounts are undersea by volcanic activity. Seamounts often have a of biological productivity because they for many species of plants and 3 is correct: Submarine Canyons are deep across the continental shelves and slopes, from the mouths of large 4 is incorrect: Guyots It is a flat-topped the seamounts is a mountain with pointed from the seafloor that does not reach the surface ocean

18. #58Practice set
    With respect to Oceanic Tides, consider the following statements: 1. Neap tides occur during full moon and new moon days. 2. Spring tides occur when the sun and the moon are at right angles to each other. 3. The spring tides are generally higher than the neap tides. 4. The tidal range is usually higher when the moon is closer to the earth.How many of the statements given above are correct?
    • AOnly one
    • BOnly two
    • COnly three
    • DAll four
    Answer: (B) Only two
    Explanation

    Option b is the correct l is incorrect: Spring tides occur when the moon and the earth are in a straight line and they a month during full moon and new moon days. that occurs during this alignment will be 2 is incorrect: Neap tides occur normally 7 spring tides when the sun, the earth and moon right angles to each other. The gravitational pulls of and sun on the earth counteract each other lide will be lower in 3 is correct: The position of the sun and a direct bearing on the height of the tide. Spring when the sun, the earth and the moon are in hence the resultant tide is higher than the Neap 4 is correct: Once in a month when the is much closer to the earth during perigee, and low tides occur in

19. #59Practice set
    Which among the following are the likely reasons for Japan having a fishing industry? l. Meeting of warm and cold ocean currents nf 2. The presence of the indented coastline along the coasts of Japan. 3. Lack of plankton on continental shelves around the coasts of Japan.Select the correct code trom Lhe upliuus given below
    • A1 and 3 only
    • B2 and 3 only
    • C1 and 2 only
    • D1, 2 and 3
    Answer: (C) 1 and 2 only
    Explanation

    Option c is the correct l is correct: The climate of Japan is the meeting of warm and cold ocean currents. zone between warm Kuroshio from the south Oyashio from the north produces fog and mist, Japan a 'second New foundland'. Due to this more favorable, replacing agriculture as the in many of the indented 2 is correct: The indented coastline of sheltered fishing ports, calm waters, and places, ideal for the fishing 3 is incorrect: The continental shelves around of Japan are rich in plankton, due to the the warm Kuroshio and the cold Oyashio currents excellent breeding grounds for all kinds of fish

20. #60Practice set
    With reference to Ocean currents, consider the following pairs:Current Feature 1. Humboldt Responsible for dry current climatic conditions prevailing in Atacama Desert. 2. Gulf stream Responsible for bringing warm water from the Gulf of Mexico to the east coast of North America. 3. Canaries current Cold ocean current that flows off the west coast of Africa.How many of the pairs given above are correctly matched?
    • AOnly one
    • BOnly two
    • CAll three
    • DNone
    Answer: (C) All three
    Explanation

    Option c is the correct 1 is correctly matched: The Atacama is one of the on earth. It receives less than 1 mm of year, and some areas haven't seen a drop of rain in 500 years. There are two main reasons for the climatic conditions in the Atacama Desert. On one Andes Mountains obstruct the moisture laden winds. other hand, Humboldt Current, which is a cold makes coastal surface water cold and of the water. When winds blow from ocean land, they will be dry and cold. These dry winds do any rain to the Atacama 2 is correctly matched: The Gulf stream is a current that flows from the Gulf of Mexico along coast of North America. It is responsible for water to the region and has a significant impact on and weather patterns in the 3 is correctly matched: The Canaries current is a current that flows off the west coast of Africa, Canary Islands and the African mainland. It is known strong winds an

21. #61Practice set
    Consider the following statements regarding the impact of Downwelling of Ocean Currents: 1. Regions of downwelling generally have low biological productivity. 2. Ekman transport plays an important role in the downwelling of ocean currents. 3. Due to downwelling, hydrogen sulfide is produced at the bottom of ocean in huge quantity.How many of the statements given above are correct?
    • AOnly one
    • BOnly two
    • CAll three
    • DNone
    Answer: (C) All three
    Explanation

    Option c is the correct l is incorrect. Earth's Geomagnetism is by a giant bar magnet placed along the axis of the earth. The magnetic field is aroused due currents produced by the convective motion fluids (consisting mostly of molten iron and the outer core of the earth. This is known as the 2 is correct. Earth's magnetic field is the earth's outer core. The Earth consists of a solid Surrounding the iron core is an ocean of hot, The liquid metal that flows in Earth's core currents, which in turn creates our magnetic 3 is correct. The Earth's magnetic field important role in protecting the planet from and cosmic radiation that are harmful. It is that protects us from harmful 4 is incorrect. Mars doesn't have flowing in its core and thus it doesn't produce the effect. This leaves the planet with a very field, allowing for its atmosphere to be by solar winds, leaving it 5 is correct. Accor

22. #62Practice set
    With reference to ocean currents, consider the following statements: 1. They help in the distribution of solar heat across the Earth. 2. They can lead to the formation of fog and storms in certain regions. 3. Some of the ocean currents help in the formation of deserts.How many of the statements given above are correct?
    • AOnly one
    • BOnly two
    • CAll three
    • DNone
    Answer: (A) Only one
    Explanation

    Option a is the correct answer. Our Solar system consists of eight planets. The nebula, our Solar system is supposed to have been its collapse and core formation some time years ago and the planets were formed about years l and 2 are solar system consists of the sun (the star), 8 planets, 200 moons, millions of smaller bodies like asteroids and huge quantity of dust-grains and of the eight planets, mercury, Venus, earth and mars as the inner planets as they lie between the sun and of asteroids the other four planets are called the Alternatively, the first four are called earth-like as they are made up of rock and have relatively high densities. Statement 3 is incorrect. The rest four planets are called Jovian or Gas Giant planets. Jovian means Jupiter-like. Most of them are much larger than the terrestrial planets and have thick of helium and hydrogen (thick atmosphere is Jovian planets)

23. #63Practice set
    Which of the following factors influence the flow of Ocean Currents? 1. Planetary winds 2. Temperature difference between the ocean waters at equator and poles 3. Variation in salinity of ocean water from place to place 4. Rotation of Earth 5. Presence of LandmassSelect the correct answer using the code given below
    • A1, 2 and 4 only
    • B2, 3 and 5 only
    • C1, 3, 4 and 5 only
    • D1, 2, 3, 4 and 5
    Answer: (B) 2, 3 and 5 only
    Explanation

    Option b is the correct Earth has a rather slight equatorial bulge: it is km (27 mi) wider at the equator than pole-to-pole. of the equator and flattening at the poles is due rotation of the Earth which creates the Centrifugal force increases as one moves from the equator and is therefore greater at the increase in centrifugal force has led to pole a result, a person on the equator is over 13 miles Earth's center than a person on the North Pole is. is more than double the distance between and the top of Mount Everest, but on a planetary bulge is virtually imperceptible. Centrifugal force is which is perpendicular to the axis of the Earth the equator

24. #64Practice set
    With reference to Ocean Floor Configuration, which of the following statements is incorrect?
    • AAbyssal plains are the largest habitat on Earth
    • BThe continental slope connects the continental shelf and the ocean basins
    • CAbyssal plains are more productive ecosystems than those along the continental shel
    • DMid-ocean ridge forms the longest mountain range on Earth
    Answer: (C) Abyssal plains are more productive ecosystems than those along the continental shel
    Explanation

    Option c is the correct waters along the continental shelf are usually ecosystem. This is due to sunlight and upwelling and land water runoff. plains are less productive ecosystems than the continental shelf. This is mainly because not penetrate to the sea floor; thus, it supports very making these deep, dark ecosystems less productive. Important Tips Ocean Floor configuration: An abyssal plain is an underwater plain on the deep ocean floor, usually al depths between 3,000 metres and 6,000 metres. They are generally found between the foot of a continental rise and a mid-ocean ridge. Abyssal plains are the largest habitat on earth. The continental slope connects the continental shelf and the ocean basins. It begins where the bottom of the continental shelf sharply drops off into a steep slope. The gradient of the slope region varies between The depth of the slope region varies between 200

25. #65Practice set
    Which of the following are located in the 30. Indian Ocean? 1. Socotra-Chagos Ridge 2. Reunion Island 3. Diamantina Trench 4. Mariana TrenchSelect the correct answer using the code given below
    • A1 and 4 only
    • B1, 2 and 3 only
    • C2, 3 and 4 only
    • D1, 2, 3 and 4
    Answer: (B) 1, 2 and 3 only
    Explanation

    Option b is the correct I is correct: Submarine ridges in this ocean Lakshadweep-Chagos Ridge [Reunion Hotspot], Chagos Ridge, the Seychelles Ridge, the Ridge, Carlsberg Ridge 2 is correct: The islands of Indian ocean include and Nicobar, Sri Lanka, Madagascar and Lakshadweep and Maldives are coral islands and the Reunion Islands are of volcanic 3 is correct: Trenches of Indian Ocean and 4 is incorrect: The Mariana Trench is a crescent shaped trench in the Western Pacific, just east of the near Guam

26. #66Practice set
    to the bottom ocean topography of Pacific, Atlantic and Indian Ocean, consider the following statements: 1. Ninety East Ridge is found in Pacific Ocean. 2. New Caledonia reef system is located in South Pacific Ocean. 3. Siberian shelf located in Arctic Ocean is the largest continental shelf on the earth. 4. The Pacific Ocean does not have oceanic ridges like Atlantic and Indian Ocean.How many of the above statements are correct?
    • AOnly one
    • BOnly two
    • COnly three
    • DAll four
    Answer: (B) Only two
    Explanation

    Option b is the correct l is incorrect. Indian ocean has the Ninety which extends from continental shelf of mouth. It runs almost North-South direction 90-degree North longitude up to 40-degree South merges with Amsterdam-St Paul Plateau in central Ridges or Mid Oceanic Ridge in Indian is known as Mid Indian Oceanic Ridges extends tip of Indian Peninsula in the North to the South almost in North-South direction and forms chain of 2 correct. The New Caledonia Barrier is located in the South Pacific is one of the in the world, covering a length of 930 miles. It is to more than 1000 different species-- some of still unclassified which live within the 3 is correct. Pacific continental shelf of represents the example of narrow shelf Atlantic continental shelf off the east coast of represents the example of medium size and extensive shelves having width of a kilometres are found off the coast

27. #67Practice set
    Consider the following statements in respect of the United Nations Convention on the Law of tl,e Sea (UN CLOS): 1. The contiguous zone extends seaward up to 12 nautical miles (nm) from the baselines. 2. Each coastal state has full sovereignty over its Exclusive Economic Zone (EEZ). 3. It established International Seabed Authority to regulate exploitation of deep seabed minerals.How many of the above statements are correct?
    • AOnly one
    • BOnly two
    • CAll three
    • DNone
    Answer: (A) Only one
    Explanation

    Option a is the correct l is incorrect: The territorial sea extends to 12 nautical miles (nm) from the baselines of the The coastal states have sovereignty and the territorial the 12-nautical-mile (22 km) limit, there is a nautical miles (22 km) from the territorial sea which is called the contiguous zone. 2 is incorrect: The exclusive economic 200 nautical mile seawards from the baseline. area, the coastal nation has sole exploitation rights natural resources. However, the coastal state does full sovereign right over the 3 is correct: The Convention has created institutions

28. #68Practice set
    to the United Nation Convention on the Lawofthe Sea (UN CLOS), Which of the following statements is/ are correct? lllo 1. The International Maritime Organisation was created under this convention. 2. The convention regulates trading activities through maritime regions. 3. The decisions of the conventions are binding on all the members.Select the correct answer using the code given below
    • A1 and 3 only
    • B3 only
    • C2 and 3 only
    • D1 only
    Answer: (B) 3 only
    Explanation

    Option (b) is the correct l is incorrect. UNCLOS has created three International Tribunal for the Law of Sea International Seabed Authority Commissions on the limit of Continental 2 is incorrect. The objectives of the To facilitate International Communications; To enable equitable and efficient utilisation of ocean resources; To protect and preserve the marine environment; To promote Maritime does not regulate trading 3 is correct. The decision of the convention on its members

29. #69Practice set
    In which of the following areas tides holds significance? 1. Navigation of ships 2. Fishing 3. Reduces river pollution 4. Generation of energySelect the correct answer using the code given below
    • A1 and 2 only
    • B1, 3 and 4 only
    • C2 and 4 only
    • D1, 2, 3 and 4
    Answer: (D) 1, 2, 3 and 4
    Explanation

    Option d is the correct l is correct. Tides help in navigation; they water level close to the shores which helps the ships harbors especially near rivers and within shallow bars at the 2 is correct. Commercial and use their knowledge of the tides and tidal help them improve their catches. Depending on the water depth in a particular area, fish may ebb or flood tidal currents. In some areas, strong concentrate bait and smaller fish, attracting Statement 3 is correct. Tides help in desilting the removal of polluted water from river 4 is correct. Tides are used to generate in many cmmtries

30. #70Practice set
    Consider the following pairs of types of tides and their explanation:Type of tide About 1. Semi-diurnal Most common tidal tide pattern with two high tides and two low tides. 2. Mixed tide These tides have variations in height. 3. Spring tide They occur twice a month, on full moon and on new moon. 4. Neap tide They occur when the sun, the moon and the earth are in a straight line.How many of the above pairs are correctly matched?
    • AOnly one
    • BOnly two
    • COnly three
    • DAll four
    Answer: (C) Only three
    Explanation

    Option c is the correct l is correctly matched. Semi-diurnal tide is the tidal pattern, featuring two high tides and tides each day. The successive high or low tides of the same 2 is correctly matched. Mixed tides are those have variations in height. These tides generally the west coast of North America and on many the Pacific 3 is correctly matched. Spring tides occur when the moon and the earth are in a straight line, the the tide will be higher. These are called spring tides occur twice a month, one on full moon period during new moon 4 is incorrectly matched. Sun, moon and earth are in line in the case of Spring tide, not in the neap the Neap tide, the sun and moon are at right angles to and the forces of the sun and moon tend to another

31. #71Practice set
    Which one of the following facto.rs is.responsihle for the change in the regular direction adi uu-u rils in the Indian Ocean?
    • AIndian is half an ocean. (h) Ocean has monsoon drift
    • B2 only
    • CIndian Ocean is a 1 and-locked ocean
    • DIndian Ocean has greater m salinity. 42
    Answer: (B) 2 only
    Explanation

    Option b is the cone ct Current, also called Monsoon Drift is the of the northern Indian Ocean. Unlike the Pacific, both of which have strong currents north of the Equator, the northern has surface currents that change with the The Monsoon winds led to the change in of ocean currents. These currents are North-East Monsoon Current and South-West Monsoon eact monr.oon winds blow from lo Lht: winter season in the northern Indian Ocean westward blowing north-east monsoon currents between Andaman and Somali. This current the south of Monsoon is complete reversal in the direction of during summer season. In other words, of winter monsoon winds becomes summer season in the northern Indian reversal of direction of monsoon winds also direction of ocean currents of northern Indian summer season. Thus, the northeast monsoon disappear and south-west monsoon ocean developed in the northern Indian Oce

32. #72Practice set
    reference to the oceanic current system in the Indian ocean region, which of the following is incorrect?
    • AOcean currcnl system in Indian ocean is strongly impacted by landmass and monsoon system
    • BNorth Indian Ocean has permanent and consistent sys Lem uf ocean currents
    • CCurrent in the Northern Indian Ocean changes direction twice a year
    • DSouthern Equatorial current is less affected by seasonal reversal of monsoon wind
    Answer: (B) North Indian Ocean has permanent and consistent sys Lem uf ocean currents
    Explanation

    Option b is the cone ct a is correct: The current systems of the are largely controlled and modified by monsoon winds. Here, Landmass includes and Indian Subcontinent. The most of the Ocean current system in Indian ocean is reversal of the ocean currents In the The absence of a temperate and polar GRAPHY north of the equator due to presence of landmass is in Indian b is incorrect: Indian ocean being the Indian Subcontinent, Africa and Australia does most favorable conditions for the development and consistent system of ocean currents. It of presence of monsoon wind system which results reversal of ocean current twice a year. In monsoon current is found and in winter, current is found. 30 so eo 10 eo 90 100 110 Warm Current 30 40 so eo 70 80 00 2 10 S. Current 10 fridian Ocean D'Gf so 0 g o West Wtnd q f 40 ), 40 Warm Current L Leeuwin c is correct: Unlike the Atlantic and Pacific, which

33. #73Practice set
    These are the western boundary ocean currents in the wind-driven, subtropical and subarctic circulations of the North Pacific Ocean. One of them is downwelling dorn.inani, low in biological productivity and is devoid of detritus and other organic material in the surface water, whereas the other is dominated by upwelling and fed by nutrient rich waters. The confluence of these currents is marked by fog banks and has a great influence on fisheries and climate in the western North Pacific These currents are
    • ACurrent and Oyashiu Currenl
    • BCalifornia Alaska Current
    • CFalkl and Current and Humbolt Current
    • DLabrador Current and Gulf Stream
    Answer: (A) Current and Oyashiu Currenl
    Explanation

    Option a is the correct answer. In the Pacific Ocean, near Hokkaido, Japan the colder Oyashio Current converges from the north with the warmer Kuroshio Current, which flows from the south. The Kuroshio and Oyashio Currents are the western boundary currents in the wind-driven, subtropical and subarctic circulations of the North Pacific Ocean. The subarctic North Pacific Ocean, on the other hand, is dominated by upwelling. The upwelled, nutrient-rich water feeds the Oyashio from the north. The confluence of these currents is marked by fogbanks and have great influence on fisheries and climate in the western North Pacific. 60" _, Major currents in the Pacific, Atlantic and Indian 6 R 6 l

34. #74Practice set
    With reference to tides, which of the following statements is/are correct? l. During perihelion, tidal ranges are much greater than average. 2. During neap tides, both high and low tides arc lower than average. 3. In diurnal tide, successive high and low tides are approximately of the sameSelect the correct answer using the code given beluw
    • A1 only
    • B1 and 2 only
    • C2 and 3 only
    • D1, 3 only
    Answer: (D) 1, 3 only
    Explanation

    Option dis the correct l is correct. During perihelion that means is closest to sun, tidal ranges are much greater 2 is incorrect. During neap tides, the bulge ocean caused by the sun partially cancels out the bulge ocean caused by the moon. This produces moderate that high tides are a little lower and low tides little higher than 3 is correct. In diurnal tide there is only tide and one low tide during each day. The and low tides are approximately of the same height

35. #75Practice set
    Which of the following statement is incorrect about Tidal currents?
    • AIt occurs in conjunction with the rise fall of Lhe tide
    • BIt is the only type of current affected by the interactions of the Earth, sun, and moon
    • CIt is generated when tides are channeled between islands
    • DDuring the full moon day the tidal current velocities arc weak
    Answer: (D) During the full moon day the tidal current velocities arc weak
    Explanation

    Option d is the correct a is correct. Tidal currents occur in the rise and fall of the tide. The vertical motion of near the shore causes the water to move b is correct. Tidal currents are the only current affected by the interactions of the Earth, moon. Tidal currents, just like tides, are affected by phases of the c is correct. Tidal currents are the tides channeled between islands or into bays and d is incorrect. When the moon is at foll phases, tidal current velocities are strong and "spring currents." When the moon is at first or phases, tidal current velocities are weak and "neap currents."

36. #76Practice set
    Consider the following statements with reference to Earth's geology: 1. The Mid-Oceanic ridges are some of the most active volcanic regions. 2. The oceanic crust is much older than the continental crust.Which of the statements given above is/are correct?
    • A1 only
    • B2 only
    • CBoth 1 and 2
    • DNeither 1 nor 2
    Answer: (A) 1 only
    Explanation

    Option a is the correct l is correct. A mid-ocean ridge or is an underwater mountain range, formed by This uplifting of the ocean floor occurs currents rise in the mantle beneath the oceanic m l ( crust and create magma where two tectonic plates meet divergent boundary. The mid-oceanic ridges are some most active regions in terms of volcanic 2 is incorrect. The continental crust is than the oceanic crust. As the continental crust destroyed and recycled in the process of sections of continental crust are nearly as old as itself. Oceanic crust is thinner and denser crust

37. #77Practice set
    Which of the following are the coral islands? 1. Lakshadweep 2. Spratly islands 3. CuracaoSelect the correct answer using the codes given below
    • A2 and 3 only
    • B1 and 2 only
    • C1 and 3 only
    • D1, 2 and 3
    Answer: (D) 1, 2 and 3
    Explanation

    Option dis the correct island: tropical island built of organic material tons of corals and uthcr unimals associated with corals. Coral islands consist of perhaps only a few ubuvc sea level, pulrns and surrounded by white coral is India's smallest Union Territory. Tt is a Spratly T.sl.inds are more than 1 SO rliffrrcnt from reef to islands scattered in the southern the South China is a coral island in the heart of the Dutch lies just a little bit to the north of Venezuela

38. #78Practice set
    Consider the following statements: 1. Mid-Oceanic ridge are the world's largest mountain ranges existing below marine waters. 2. The occurrence of shallow earthquakes near mid ocean ridges is due to divergence of the tectonic plates.Which of the statements given above is/are correct?
    • A1 only
    • B2 only
    • CBoth 1 and 2
    • DNeither 1 nor 2
    Answer: (C) Both 1 and 2
    Explanation

    F.xp) Option c is the correct l is correct. Mid Oceanic Ridges are mountain like structures standing well above the deep ocean mid oceanic ridges are, in total, 65,000 km long almost of the earth's surface. These are the world's largest mountain ranges existing waters. They exist as chains, in the centre of 2 is correct. The mid oceanic ridges are the boundary between two divergent tectonic zones are tectonically active regions. Hence, occur frequently on crests of mid ocean ridges

39. #79Practice set
    With reference to movement of tides, which of the forces for tidal movement?
    • AWinds
    • BGravitational pull of Sun
    • CSalinity difference between the surface zones and deep zones of the ocean
    • DTemperature difference at surface of the ocean
    Answer: (B) Gravitational pull of Sun
    Explanation

    Option b is the correct periodical rise and fall of the sea level, once or twice mainly due to the attraction of the sun and the called a pull of sun and moon are the forces movement of winds, temperature difference are in formation and movement of oceanic currents are not responsible for formation of moon's gravitational pull to a great extent and to a the sun's gravitational pull, are the major causes occurrence of tides. Another factor is centrifugal is the force that acts to counter balance the the pull and the centrifugal force for creating the two major tidal bulges on Movement of water catwcd by mctcurologic.il winds aml atmospheric are called surges. Surges are not tided and are like tides

40. #80Practice set
    Consider the following slakments: 1. The variation in temperature over the sea is less compared to land. 2. The places located on the coast where the warm ocean currents flow, record higher temperature.Which of the statements given above are correct?
    • A1 only
    • B2 only
    • CBoth 1 and 2
    • DNeither 1 nor 2
    Answer: (C) Both 1 and 2
    Explanation

    Option c is the correct l is correct: Coriolis Force is a responsible for the deflection in the flow of fluid systems (winds and ocean currents) 2 is correct: The Coriolis force acts in a to the angular velocity of the rotating 3 is correct: The Coriolis Force is to the angle of latitude. As the latitude horizontally and freely moving objects are the twisting of the underlying Earth's its velocity due to the planet's rotation increases. Coriolis Force is maximum at the Poles and at the 4 is incorrect: The Coriolis Force is following factors

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