These questions-answer will be useful for UPSC, UPPSC, and other Civil Service Prelims Examinations.
1. In reference of the location of the world's deserts
consider the following statements :
1. Almost all the deserts located within the 15 degree to 30
degree of North and South latitude of the equator.
2. They located on the the Western parts of the continents.
3. Due to worm ocean currents, there is no 'desicating
effect'.
Which of the statement given ever is/are CORRECT ?
(a) 1 and 3 Only
(b) 2 Only
(c) 1 and 2 Only
(d) 1, 2 and 3
Answer (c)
By the careful study
of world map, there is certain definite pattern to location of the world's
deserts.
Statement 1 is correct: Most of the world's deserts
are confined within 15 degree to 30 degree parallels of latitude North and
South of the Equator. They include the great Sahara, Thar, Kalahari, Namib,
etc.
Statement 2 is correct: They lie in the trade wind
belt on the western parts of the continents where Trade winds are off-shore.
Statement 3 is not correct: Deserts are bathed by
cold ocean currents which produce a 'desicating effect' so that moisture is not
easily condensed into precipitation. Dryness or aridity is the key note. Such
deserts tropical hot deserts or 'Trade Wind Deserts'.
2. In context of desert, consider the following
statements
1. Desert occupy 1/5th of the world’s land
2. All deserts are absolutely barren and nothing grow
Select the CORRECT code given below
(a) 1 Only
(B) 2 Only
(c) Both 1 and 2
(d) None of These
Answer: (a)
Explanation:
About 1/3rd
of the land surface of the world is arid or semi-arid, in which 1/5th
of the world’s land is made up of deserts.
Statement 1 is correct:
Deserts are found on every continent and cover about one-fifth of
Earth’s land area. They are home to around 1 billion people—one-sixth of the
Earth’s population.
Statement 2 is not correct: Deserts that are
absolutely barren and where nothing grows at all are rare and they are better
known as ‘true
deserts’.
A desert is a barren area of landscape where little
precipitation occurs and, consequently, living conditions are hostile for plant
and animal life. It is classified as hot deserts or cold deserts. Extreme
temperatures combined with little rainfall make desert life difficult for
people, plants, and animals.
3. What could be the main reason/reasons for the
formation of deserts?
1. Extreme Temperature
2. High Precipitation
3. High Evaporation
Which of the statements given above is/are CORRECT in
this context?
(a) 1 and 2 Only
(b) 2 and 3 only
(c) 1 and 3 Only
(d) 1, 2 and 3
Answer (c)
Explanation: One thing all deserts have in common is that
they are arid, or dry. The ideal condition for desert is extreme temperature,
low precipitation (rainfall) and high evaporation.
Statement 1 is correct: Although some deserts are very
hot, with daytime temperatures as high as 54°C (130°F), other deserts have cold
winters or are cold year-round. And most deserts, far from being
empty and lifeless, are home to a variety of plants, animals, and other
organisms.
Temperature extremes are a characteristic of most
deserts. In some deserts, temperatures rise so high that people are at risk of
dehydration and even death. At night, these areas cool quickly because they
lack the insulation provided by humidity and clouds. Temperatures can drop to
4°C (40°F) or lower.
Statement 2 is not correct: According
to geographers/geologists, a desert is an area of land that receives no more
than 25 centimetres (10 inches) of precipitation a year.
Statement 3 is correct: The amount of evaporation (High
Evaporation) in a desert often greatly exceeds the annual rainfall. In all
deserts, there is little water available for plants and other organisms.
4. The world’s desert landscape in the form of
1. Rocky
2. Sandy
3. Stony
Which of the following code given below is CORRECT?
(a) 1 and 2 Only
(B) 2 and 3 Only
(c) 1 and 3 Only
(d) 1, 2 and 3
Answer (d)
Explanation:
The desert landscape forms can exist in the some rocky,
others stony and the rest sandy.
Statement 1 is correct: Hamada or Rocky desert. This
consists of large stretches of bare rocks, swept clear of sand and dust by the
wind. The exposed rocks are thoroughly smoothed and polished. The region
is bare and sterile. The best known rocky deserts are those of the Sahara
Desert e.g. the Hamada el Homra, in Libya, which covers an area of almost
20,000 square miles.
Statement 2 is correct: Erg or Sandy desert. This is
a sea of sand which typifies the popular idea of desert scenery. Winds deposit
vast stretches of undulating sand-dunes in the heart of the deserts. The
intricate patterns of ripples on the dune surfaces indicate the direction of
the winds. The Calanscio Sand Sea in Libya is characteristic of a sandy desert.
In Turkestan, sandy deserts are also known as koum.
Statement 3 is correct correct: Reg or Stony desert.
is composed of extensive sheets of angular pebbles and gravels which the winds
are not able to blow off. Such stony deserts are much more accessible than the
sandy deserts, and large herds of camels are kept there. In Libya and Egypt the
term serir is used; elsewhere in Africa, stony deserts are called reg.
5. Which of the following statement related to Weathering
process in desert?
1.
Exfoliation of rocks
2.
Slow weathering due to lack of water
3.
Extreme temperature caused fast weathering
Select the CORRECT answer code given below
(a)
1 and 2 Only
(b)
2 and 3 Only
(c)
1 and 3 Only
(d)
1, 2 and 3
Answer (d)
Explanation:
Weathering is the most potent
factors in reducing rocks to sand in arid regions. Even though the amount of
rain that falls in the desert is small some manage to penetrate into the rocks
and sets up chemical reactions in the various minerals.
Statement 1 is correct: The
heating of the rocks causes the outer surface to expand and so prise itself off
from the interior rocks, so that it peels off in successive very thin layers.
Such an onion-peeling process of mechanical weathering is called exfoliation.
Statement 2 is correct: Water
is the main agent of weathering, and lack of water slows weathering.
Precipitation occurs in deserts, only less than in other climatic regions.
Statement 3 is correct:
Intense heating during the day and rapid cooling at night by radiation (This
phenomenon is known as extreme temperature), set up stresses in the already
weakened rocks so that they eventually crack.
6. In reference of desert erosion, What is/are mechanism
of erosion?
(a) Weathering
(b) Wind Action
(c) Both (a) and (b)
(d) None of These
Answer (c)
Explanation:
Arid landforms are the results of many combined factors, one
reacting upon the other. Insufficient rainfall often irregular periods, coupled
with very high temperatures (87 F. is the average) and a rapid rate of
evaporation, are the chief causes of aridity. Sub-aerial denudation through the
processes of weathering (mechanical and chemical), wind action and the work of
water have combined to produce a desert landscape that is varied and
distinctive less than 5 inches) coming at most
Option (a) is correct: Weathering is the most potent
factors in reducing rocks to sand in arid regions. Intense heating during the
day and rapid cooling at night by radiation, set up stresses in the already
weakened rocks so that they eventually crack. As heat penetrates rocks slowly
when the outer surface of rocks is being heated by the hot sun, the inner rocks
remain quite cool. The heating of the rocks causes the outer surface to expand
and so prise itself off from the interior rocks, so that it peels off in
successive very thin layers. Such an onion-peeling process of mechanical
weathering is called exfoliation.
Option (b) is correct: Action of winds in deserts.
The wind though not the most effective agent of erosion, transportation and
deposition, is more efficient in arid than in humid regions. Since there is
little vegetation or moisture to bind the loose surface materials, the effects
of wind erosion are almost unrestrained.
Wind erosion is carried out in the following ways:
1. Deflation : Removal of sand and dust particles by wind.
It forms depression in the desert. When depression is filled with water, it is
called as Oasis.
2. Abrasion : Action of wind in which sand particles carried
by the wind strike against the rock.
3. Attrition : Sand particles carried by the wind striking
each other is known as attrition.
7. In refence of the Inselberg, Which of the following
statement is CORRECT?
(a) Landforms of wind deposition in desert
(b) Landforms of wind erosion in desert
(c) Residual hills with very gentle slope
(d) Inselberg means Ridge
Answer (b)
Explanation:
Inselberg: This is a German word meaning island-mountain’.
They are isolated residual hills rising abruptly from the level ground. They
are characterized by their very steep slopes and rather rounded tops.
They are often composed of granite or gneiss, and are probably the relics of an
original plateau which has been almost entirely eroded away. Inselbergs are
typical of many desert and semi-arid landscapes in old age e.g. those of
northern Nigeria, Western Australia and the Kalahari Desert.
Additional Read : Desert Landforms and Erosion Mechanism
8. Which is not the erosional desert landforms due to
wind action?
(a) Yardangs
(b) Zeugen
(c) Inselberg
(d) Dunes
Answer (d)
Explanation:
Option (d) is correct: Dunes are out come of the wind
deposition in desert. Dunes are most well represented in the erg desert
where a sea of sand is being continuously moved, reshaped and redeposited into
a variety of features.
Yardangs: Quite similar to the ‘ridge and furrow
landscape of zeugen are the steep-sided yardangs. Instead of lying in
horizontal strata upon one another, the hard and soft rocks of yardangs are vertical
bands and are aligned in the direction of the prevailing winds. Wind
abrasion excavates the bands of softer rocks into long, narrow corridors,
separating the steepsided over-hanging ridges of hard rocks, called yardangs.
They are commonly found in the Atacama Desert, Chile, but the more
spectacular ones with yardangs rising to 25-50 feet are best developed in the
interior deserts of Central Asia where the name originated.
Zeugen: These are tabular masses which have a
layer of soft rocks lying beneath a surface layer of more resistant rocks. The
sculpting effects of wind abrasion wear them into a weird-looking ‘ridge
and furrow’ landscape. Mechanical weathering initiates their formation by
opening up joints of the surface rocks. Wind abrasion further ‘eats’ into the
under- lying softer layer so that deep furrows are developed. The hard rocks
then stand above the furrows as ridges or zeugen , and many even
overhang. Such tabular blocks of zeugen may stand 10 to 100 feet above the
sunken furrows. Continuous abrasion by wind gradually lowers the zeugen and widens the furrows.
Inselberg: This is a German word meaning island-mountain’.
They are isolated residual hills rising abruptly from the level ground. They
are characterized by their very steep slopes and rather rounded tops. They are
often composed of granite or gneiss, and are probably the relics of an original
plateau which has been almost entirely eroded away. Inselbergs are typical of
many desert and semi-arid landscapes in old age e.g. those of northern Nigeria,
Western Australia and the Kalahari Desert.
9. Which of the following pairs is/are CORRECTLY match?
Landforms Action
1.
Barchan
Wind Deposition
2.
Seifs Wind Deposition
3.
Bajada Water Deposition
4.
Messa
Water Erosion
Select the correct answer using the code given below
(a) 1, 2 and 3
(B) 1, 2 and 4
(c) 1, 3 and 4
(d) 1, 2, 3 and 4
Answer (a)
Explanation:
Desert Landforms due to action of winds in deserts. The wind
though not the most effective agent of erosion, transportation and deposition,
is more efficient in arid than in humid regions. Since there is little
vegetation or moisture to bind the loose surface materials, the effects of wind
erosion are almost unrestrained.
Pair 1 is correct : Barchan – These are crescentic or moon- shaped
dunes which occur individually or in groups. They are live dunes which advance
steadily before winds that come from a particular prevailing direction. They
are most prevalent in the deserts of Turkestan and in the Sahara.
Pair 2 is correct : Seifs or Longitudinal dune – Seif
is an Arabic word meaning 'sword'. They are long, narrow ridges of sand,
often over a hundred miles long lying parallel to the direction of the
prevailing winds. Extensive seif dunes are found in the Sahara Desert, south of
the Qattara Depression; the Thar Desert and the West Australian Desert.
Pair 3 is correct : The bajada is a de-
positional feature made up of alluvial material laid down by the intermittent
streams.
Pair 4 is not correct : Mesa is a Spanish word
meaning ‘table’. It is a flat, table-like land mass with a very
resistant horizontal top layer, and very steep sides. The hard stratum on the
surface resists denudation by both wind and water, and thus protects the
underlying layers of rocks from being eroded away. Mesas may be formed in
canyon regions e.g. Arizona, or on fault blocks e.g. the Table Mountain of Cape
Town, South Africa. Continued denudation through the ages may reduce mesas in
area so that they become isolated flat-topped hills called buttes. Many of them
in arid countries are separated by deep gorges or canyons. (by action of wind
erosion).
10. Which of the following pair is/are CORRECTLY match?
(a) Gobi Desert : Cold Desert
(b) Pantagonia Desert : Hot Desert
(c) Kalahari Desert : Cold Desert
(d) All of These
Answer (a)
Explanation :
The Gobi is a cold desert and semidesert region of Central
Asia. The Gobi (from the Mongolian Gobi, meaning “waterless place”)
stretches across huge portions of both Mongolia and China.
The Gobi desert is bounded by the Altai Mountains and the
grasslands and steppes of Mongolia on the north, and Tibetan Plateau to the
southwest, and by the North China Plain to the southeast.
Option (b) is not correct : Patagonia, semiarid scrub
plateau that covers nearly all of the southern portion of mainland Argentina.
With an area of about 260,000 square miles (673,000 square kilometres), it
constitutes a vast area of steppe and desert that extends south from latitude
37° to 51° S. It is bounded, approximately, by the Patagonian Andes to the
west, the Colorado River to the north (except where the region extends north of
the river into the Andean borderlands), the Atlantic Ocean to the east, and the
Strait of Magellan to the south; the region south of the strait—Tierra del
Fuego, which is divided between Argentina and Chile—also is often included in
Patagonia. It is a Cold Desert.
Option (c) is correct : The Kalahari Desert is one of
the large semi-arid regions that are dominated by sand savannah
landscape in South Africa. Despite the name given to the Kalahari Desert, it is
does not have desert conditions due to the fact that it receives heavy rainfall
that is between 5 to 10 inches per year. However the despite the fact the place
receives a lot of rains the water is filtered very fast by the sweeping
savannah landscape.
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