[DAY 31] 60 DAY RAPID REVISION (RaRe) SERIES for UPSC Prelims 2022 – GEOGRAPHY, CURRENT AFFAIRS & CSAT; Test Series, Videos & Notes!

Solution (d)

Basic Info:

About 71% of our earth is covered by water. Out of which 97% of the earth’s water is found in the oceans. 3% of the earth’s water is fresh.

Distribution of Water in %

• Ocean = 97.25
• Ice caps and glaciers= 2.05
• Groundwater = 0.68
• Lakes = 0.01
• Soil Moisture = 0.005
• Atmosphere = 0.001
• Streams and Rivers = 0.0001
• Biosphere = 0.00004

Solution (a)

Basic Info:

The continental shelf is the extended margin of each continent occupied by relatively shallow seas and gulfs. It is the shallowest part of the ocean showing an average gradient of 1° or even less. The shelf typically ends at a very steep slope, called the shelf break.

The shelf is formed mainly due to

• Relative rise in sea level
• Submergence of a part of a continent
• Sedimentary deposits brought down by rivers

The width of the continental shelves vary from one ocean to another. The average width of continental shelves is about 80 km. The shelves are almost absent or very narrow along some of the margins like the coasts of Chile, the west coast of Sumatra, etc. On the contrary, the Siberian shelf in the Arctic Ocean, the largest in the world, stretches to 1,500 km in width.

The depth of the shelves also varies. It may be as shallow as 30 m in some areas while in some areas it is as deep as 600 m.

The continental shelves are covered with variable thicknesses of sediments brought down by rivers, glaciers, wind, from the land and distributed by waves and currents. Massive sedimentary deposits received over a long time by the continental shelves, become the source
of fossil fuels.

Solution (d)

Basic Info:

John Murray has classified ocean deposits into two broad categories based on the settlement locations.

1. The terrigenous deposits: These are found on the continental shelves and slopes and mainly consist of the rock material derived because of wear and tear.
2. The pelagic deposits: These are found over deep sea plains. These deposits mainly consist of organic remains of plants and animals.
3. Terrigenous Deposits:

– Terrigenous deposits are derived from the wear and tear of land and volcanic and organic products found majorly in the continental slope and shelf areas.

– On the basis of size of particles, the terrigenous deposits may be categorised into three classes— mud, sand and gravel.

2. Pelagic deposits:

-Pelagic deposits comprise 75% of the total sea floor. They consist of both organic and inorganic materials.

– Organic materials are in the form of a kind of liquid mud, called ooze, which contains shells and skeletons of various marine organisms.

– The ooze is said to be calcareous when the shell is made of calcium carbonate.

-Inorganic materials are in the form of red clay of volcanic origin.

-The chief constituents of red clay are silicon and aluminium dioxide, while other constituents include iron, manganese, phosphorus and radium. The red clay is the most widely spread pelagic deposit and covers 38% of the sea floor.

Solution (d)

Basic Info:

Geysers:
– Geysers are fountains of hot water and superheated steam that may spout up to a height of 150 feet from the earth’s beneath.

– The jet of water is usually emitted with an explosion.

– They are associated with volcanic regions or volcanic activity.

– Examples include Great Geyser of Iceland, Yellowstone National Park etc.

Hot Springs:
– In hot springs water rises to the surface without any explosion.

– In this water sinks deep enough beneath the surface to be heated by the interior forces.

– Such springs contain dissolved minerals.

-Examples include the hot springs of Yellowstone national park.

Solution (c)

Basic Info:

Estuaries:

-An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it and with a free connection to the open sea.

Estuaries are formed due to rise in sea level, movement of sand and sandbars, glacial processes and tectonic processes.

Estuaries form a transition zone between river environments and maritime environments known as ecotone.

Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water and to riverine influences such as flows of freshwater and sediment.

The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment making estuaries among the most productive natural habitats in the world.

Examples of estuaries are river mouths, coastal bays, tidal marshes, lagoons and deltas.

Solution (a)

Basic Info:

–The Agulhas Current is the western boundary current of the South-West Indian Ocean. It flows down the east coast of Africa. The source water at its northern end is derived from Mozambique channel eddies and the East Madagascar Current, but the greatest source of water is recirculation in the southwest Indian Ocean sub-gyre. Hence pair 1 is correctly matched.

-The Irminger Current is a north Atlantic ocean current setting westward off the southwest coast of Iceland. It is composed of relatively warm and saline waters from the eastern North Atlantic that are fed by the North Atlantic Drift. The Irminger Current is part of the North Atlantic subpolar gyre. Hence pair 2 is not correctly matched.

–The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America. Hence pair 3 is correctly matched.

Solution (b)

Basic Info: -The ocean floors can be divided into four major divisions: (i) the Continental Shelf; (ii) the Continental Slope; (iii) the Deep Sea Plain; (iv) the Oceanic Deeps.

-Besides, these divisions there are also major and minor relief features in the ocean floors like ridges, hills, sea mounts, guyots, trenches, canyons, etc.

Continental Shelf: The continental shelf is the extended margin of each continent occupied by relatively shallow seas and gulfs. It is the shallowest part of the ocean showing an average gradient of 1° or even less.

Continental Slope: 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.

Continental Rise: The continental rise is found between the continental slope and the abyssal plain. It represents the final stage in the boundary between continents and the deepest part of the ocean. At the bottom of the continental slope, one will find the continental rise, an underwater hill composed of tons of accumulated sediments.

Abyssal Plain: The abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 4,000 metres and 6,000 metres. It lies between the foot of a continental rise and a mid-ocean ridge.

Solution (d)

Basic Info:

An artesian basin is a low-lying region where groundwater is cramped under pressure from surrounding layers of rock. These basins are usually found where an aquifer is present in a syncline, by impenetrable layers above as well as below.

Whenever a fissure breaks the surface, the underground water blow up. This results in the rising of the water level to a point where hydrostatic equilibrium has been achieved.

The Great Artesian Basin is one of the largest underground water reservoirs in the world. It underlies approximately 22 per cent of Australia, occupying an area of over 1.7 million square kilometres beneath the arid and semi-arid parts of Queensland, New South Wales, South Australia and the Northern Territory.

Solution (c)

Basic Info:

According to the recently released IPCC’s Report, Atlantic Meridional Overturning Circulation (AMOC) is losing its stability and is very likely to decline over the 21st century.

About AMOC:

It is a large system of ocean currents.

It is the Atlantic branch of the ocean conveyor belt or ThermoHaline Circulation (THC), and distributes heat and nutrients throughout the world’s ocean basins.

Working of AMOC:

AMOC carries warm surface waters from the tropics towards the Northern Hemisphere, where it cools and sinks.

It then returns to the tropics and then to the South Atlantic as a bottom current. From there it is distributed to all ocean basins via the Antarctic Circumpolar Current.

The ACC is the most important current in the Southern Ocean, and the only current that flows completely around the globe.

Implications of decline of AMOC:

Without a proper AMOC and Gulf Stream, Europe will be very cold.

Gulf Stream, a part of the AMOC, is a warm current responsible for mild climate at the Eastern coast of North America as well as Europe.

An AMOC shutdown would cool the northern hemisphere and decrease rainfall over Europe.

It can also have an effect on the El Nino.

Solution (c)

Basic Info:

The Department of Water Resources, River Development, and Ganga Rejuvenation (DoWR, RD & GR) released the Glacial Lake Atlas of Ganga Basin.

About the Glacial Lake Atlas:

• The present glacial lake atlas is based on the inventoried glacial lakes in part of Ganga River basin from its origin to foothills of Himalayas covering a catchment area of 2,47,109 sq. km.
• Glacial Lake Atlas is to Be Used In Carrying Out Climate Change Impact Analysis And Disaster Mitigation Planning
• The study portion of Ganga River basin covers part of India and transboundary region.
• The Ganga River Basin Atlas is brought out under the National Hydrology Project (NHP).
• The atlas is prepared with the efforts of the National Remote Sensing Centre (NRSC), ISRO under the National Hydrology Project (NHP).

Solution (c)

Basic Info:

About Fukutoku-Okanoba volcano:

• In Sept 2021, Fukutoku-Okanoba Submarine Volcano exploded in the Pacific Ocean, off Japan that may poses a risk to the passage of planes and ships.
• The Fukutoku-Okanoba volcano is situated about 25 metres (80 feet) below the sea five kilometres north of Japan’s South Iwo Jima Island.
• The plume reached a height of 16 kilometres above the surface, posing a risk to the passage of planes and ships.

Submarine volcanoes:

• Submarine volcanoes are erupting basaltic lavas and new crust material is actively formed with substantial piles of pillow lavas.
• Submarine volcanoes are underwater vents or fissures in the Earth’s surface from which magma can erupt.
• Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges.
• The volcanoes at mid-ocean ridges alone are estimated to account for 75% of the magma output on Earth.

Solution (b)

Basic info:

Coral Reefs:

As a rule, corals thrive well only in the warmer tropical seas. But there are deep water corals also that are found in deeper and darker parts of the ocean where temperatures may be as cold as 4 degrees Celsius.

-In tropical seas, many kinds of coral animals and marine organisms such as coral polyps,
calcareous algae, shell-forming creatures and lime-secreting plants live in large colonies.

-Though they are very tiny creatures, their ability to secrete calcium carbonate within their tiny cells has given rise to a peculiar type of marine landform. Each polyp resides in a tiny cup of coral and helps to form coral reefs.

-When they die, their limy skeletons are cemented into coralline limestone.

Conditions for reef formation
The reef-building corals survive best under the following conditions:

The water temperature must not fall below 68°F (20°C):
 -This limits the areal distribution of corals to the tropical and sub-tropical zones.

-Again they will not flourish where there are cold currents because of the upwelling of the cold water from the depths that cools the warm surface water. This explains why coral reefs are generally absent on the western coasts of continents.

-On the other hand, the warming effect of the warm currents, e.g. the Gulf Stream, means that corals are found far to the north of the West Indies in the Atlantic Ocean. The Pacific and
the Indian Oceans, however, have the most numerous coral reefs.

-There are also non-reef- building species of corals such as the ‘precious corals’ of the Pacific Ocean and the ‘red coral’ of the Mediterranean which may survive in the colder and even the deeper waters.

The depth of the water should not exceed 30 fathoms or 180 feet:
-Beyond this depth sunlight is too faint for photosynthesis to take place. This is essential for the survival of the microscopic algae, on which the coral polyps depend. Shallow water of less
than 100 feet is ideal. But there should always be plenty of water as polyps cannot survive for too long out of water.

The water should be salty and free from sediment:
-Corals therefore survive best in the moving ocean water well away from the silty coasts or muddy mouths of streams.

–The corals are best developed on the seaward side of the reef, where constantly moving waves, tides and currents maintain an abundant supply of clear, oxygenated water. They also bring an adequate supply of food in the form of microscopic organisms.

Solution (c)

Basic info:

-Ocean currents are like river flow in oceans. They represent a regular volume of water in a definite path and direction.

-Ocean currents are influenced by two types of forces namely:

(i) Primary forces that initiate the movement of water;

(ii) Secondary forces that influence the currents to flow.

The primary forces that influence the currents are:

• wind
• gravity
• coriolis force
• heating by solar energy

-Heating by solar energy causes the water to expand. That is why, near the equator the ocean water is about 8 cm higher in level than in the middle  latitudes. This causes a very slight gradient and water tends to flow down the slope.

– Wind blowing on the surface of the ocean pushes the water to move. Friction between the wind and the water surface affects the movement of the water body in its course.

– Gravity tends to pull the water down the pile and create gradient variation.

– The Coriolis force intervenes and causes the water to move to the right in the northern hemisphere and to the left in the southern hemisphere.

Solution (a)

Basic Info:

Ground Water:

Any limestone or dolomitic region showing typical landforms produced by the action of groundwater through the processes of solution and deposition is called Karst topography after the typical topography developed in limestone rocks of Karst region in the Balkans adjacent to Adriatic sea.

It is this downward and horizontal movement of water that causes the rocks to erode. Physical or mechanical removal of materials by moving groundwater is insignificant in developing landforms.

The karst topography is also characterised by erosional and depositional landforms.

• Erosional Landforms: pools, sinkholes, lapies and caves.
• Depositional Landforms: stalactites, stalagmites and pillars.

Solution (b)

Basic Info:

In the South Pacific Ocean, the South Equatorial Current flows towards the west and turns
southward as the East Australian Current.

From Tasmania, it flows as the cold South Pacific Current from west to east and crosses the
Pacific Ocean along with the West Wind Drift.

On reaching the south-western coast of South America, it turns northward and flows as the
cold Peru Current or Humbolt Current.

The cold waters of the Peru Current are partially responsible for making the coast of the
northern Chile and western Peru with very scanty rainfall.

Peru Current eventually joins with the South Equatorial Current and completes the circuit.

The pattern of circulation of ocean currents in the Indian Ocean differs from the general
pattern of circulation in the Atlantic and the Pacific Oceans. This is because the Indian Ocean is blocked by the continental masses in the north.

The general pattern of circulation in the southern hemisphere of the Indian Ocean is anticlockwise as that of the other oceans.

In the northern hemisphere, there is a clear reversal of currents in the winter and summer
seasons, which are completely under the influence of the seasonal changes of monsoon
winds.

Solution (d)

Basic Info

Low Sedimentary Coasts:

• Along low sedimentary coasts, the rivers appear to extend their length by building coastal plains and deltas.
• The coastline appears smooth with occasional incursions of water in the form of lagoons and tidal creeks. The land slopes gently into the water.
• Marshes and swamps may abound along the coasts. Depositional features dominate.

Solution (a)

Basic Info

Vertical Distribution of Salinity:

Salinity at the surface increases by the loss of water to ice or evaporation, or decreased by
the input of fresh waters, such as from the rivers. Therefore at the surface salinity varies.

Salinity at depth is very much fixed, because there is no way that water is ‘lost’, or the salt is ‘added.’

There is a marked difference in the salinity between the surface zones and the deep zones of the oceans.

The lower salinity water rests above the higher salinity dense water.

Salinity, generally, increases with depth and there is a distinct zone called the halocline,
where salinity increases sharply.

Other factors being constant, increasing salinity of seawater causes its density to increase.

High salinity seawater, generally, sinks below the lower salinity water. This leads to stratification by salinity.

Solution (a)

Basic Info

Ocean currents can also be classified based on temperature  as cold currents and warm currents:

Cold currents bring cold water into warm water areas. These currents are usually found on the west coast of the continents in the low and middle latitudes (true in both hemispheres) and on the east coast in the higher latitudes in the Northern Hemisphere

Warm currents bring warm water into cold water areas and are usually observed on the east coast of continents in the low and middle latitudes (true in both hemispheres). In the northern hemisphere they are found on the west coasts of continents in high latitudes.

Solution (c)

Basic Info:

The Pensilungpa Glacier is located in Zanskar, Ladakh. It is retreating due to an increase in the temperature and decrease in precipitation during winters.

South Col Glacier: The South Col is a sharp-edged col between Mount Everest and Lhotse, the highest and fourth-highest mountains in the world, respectively. ( Two cirques is called a col )

At a mean elevation of 7,985 mean sea level, this glacier is the highest glacier in the world.

Recent studies have found that SCG has lost more than 54m of thickness in the last 25 years.

Solution (c)

Basic Info:

The periodical rise and fall of the sea level, once or twice a day, mainly due to the attraction of
the sun and the moon, is called a tide.

Movement of water caused by meteorological effects (winds and atmospheric pressure
changes) are called surges. Surges are not regular like tides.

Causes for occurrences of tides:

• The moon’s gravitational pull
• The sun’s gravitational pull,
• Another factor is centrifugal force, which is the force that acts to counter balance the gravity.

Together, the gravitational pull and the centrifugal force are responsible for creating the two major tidal bulges on the earth.

The ‘tide-generating’ force is the difference between these two forces; i.e. the gravitational
attraction of the moon and the centrifugal force.

On the surface of the earth, nearest the moon, pull or the attractive force of the moon is greater than the centrifugal force, and so there is a net force causing a bulge towards the moon.

On the opposite side of the earth, the attractive force is less, as it is farther away from the moon, the centrifugal force is dominant. Hence, there is a net force away from the moon. It creates the second bulge away from the moon.

On the surface of the earth, the horizontal tide generating forces are more important than the vertical forces in generating the tidal bulges.

Solution (d)

  Statement Analysis:   

 Context – Sahitya Akademi Awards were announced.

Solution (c)

   Union Social Justice and Empowerment said it had formulated an umbrella scheme, SMILE

(Support for Marginalised Individuals for Livelihood and Enterprise), that included two

sub-schemes for the welfare of transgender persons and persons engaged in begging. The

scheme will cover rehabilitation, provision of medical facilities, counselling, education, skill

development and economic linkages.

Context –  SMILE  scheme was in news

Solution (a)  

Statement Analysis:

Context – Nuclear powers vowed to halt the spread of nuclear weapons.

Solution (b)

Statement Analysis:

 Context – ICMR approved India made kit for the detection of COVID-19.

Solution (b)

Statement Analysis:

 Context – Ex RBI Governor Urjit Patel was appointed to the Board of Governors of Asian Infrastructure Investment Bank (AIIB).

Solution (b)

Milk in the original mixture = 60% of 80 litres = 48 litres

Water in the original mixture =40% of 80 litres = 32 litres

Similarly, out of the 20 litres taken out , milk = 12 litres and water = 8 litres

So, after taking out 20 litres, milk = 48 – 12 = 36 litres.

Water = 32 -8 = 24 litres

Adding 20 litres of water makes it,24 + 20 = 44 litres.

Final ratio of milk and water is 36:44, which is equal to 9:11

Solution (b)

Consider the amount of rice of price Rs7.5 =x

And the amount of rice of price Rs10 =y

Then the total amount of mixture =7.5x+10y

But the price per kg of mixture =Rs8.25

So, total price of x+y kg =8.25(x+y)

Now according to the equation 8.25(x+y)=7.5x+10y

8.25x+8.25y=7.5x+10y

0.75x=1.75y

x/y ​ = 1.75/0.75 ​

= 7/3 ​

Hence, required Ratio is 7:3

Solution (a)

Water : Oil = 3:5

Let’s assume the volume of the vessel is 80 Litres.

Water = 30 Litres ,oil = 50 Litres

Since all the liquid taken out of the vessel is replaced by water, the total volume remains constant.

Therefore, we need to ensure there’s 40 litres of water and oil individually.

Therefore, we need to take out 10 litres of oil and replace it with water.

The ratio of Water to oil is 3:5.

Hence, 8 Litres of the solution would have 3 Litres of water, and 5 Litres of oil.

Now, if we replace these 8 litres with 8 litres of water, then we have essentially replaced these 5 litres of oil with water.

Therefore, we need to replace 16 litres, or 20% of the solution with water.

16 litres of 80 litres turns out to be 1/5.

Solution (d)

Let the price of milk be ‘x’ per litre

The cost of milk for 15 litres = 15x

Now, after mixing 3 litres of water, quantity of mixture = (15+3) litres = 18 litres

Price of the mixture is 22 per litre.

15x = 22* 18

X= (22*18)/15

X= 26.40 rupees

Solution (b)

The paragraph argues that political homogenisation is as toxic to public discourse as political polarisation. To support this, the paragraph puts forth two main points. The first one is that where agreement is sought without a “decent” or “appropriate” discussion, there are “opinion corridors”. The ideas tolerated in public discourse get limited and discussion is subdued. The second point the paragraph makes is that when a culture buries difficult conversations, it sets the stage for the rise of populism as populist rhetoric resonates with those segments of the population that have a pent up need to be heard.

Option b captures both these ideas, and is the best one to sum up the paragraph.

Option a talks of “political ambivalence”. This is not discussed in the paragraph.

Option c is very close, but while it speaks of one of the ideas in the paragraph, it doesn’t touch upon the point about populist rhetoric.

That political polarisation leads to populism is not clear from this paragraph. So, option d is incorrect.