Physical Geography (UPSC) (Part-III)

Total Questions: 44

1. “Climate is extreme, rainfall is scanty and the people used to be nomadic herders.” [2013-I]

Correct Answer: (b) Central Asian Steppe
Solution:The central Asian steppes run through Kazakhstan, Turkmenistan, Uzbekistan, and Mongolia. The climate here is harsh with dust storms, little to no rainfall, and temperature ranging from –4 to 50 degrees Celsius.

About the Steppe

  • A steppe is a large, open grassland biome found in regions with semi-arid climates, typically in the temperate zones of the Northern Hemisphere. Characterized by vast, treeless expanses, steppes have low annual rainfall (250–500 mm), hot summers, and cold winters, with significant temperature variations.
  • The vegetation primarily consists of drought-resistant grasses and herbs, making it ideal for grazing animals such as sheep, goats, and horses.
  • Steppes are vital ecosystems that support diverse wildlife, including marmots, antelopes, and various bird species.
  • They play an essential role in soil conservation, carbon storage, and maintaining ecological balance. Historically, steppes like those in Central Asia and Eastern Europe served as migration routes and homelands for nomadic cultures, influencing trade and cultural exchange along routes like the Silk Road.
  • However, modern threats such as overgrazing, agriculture, and climate change have impacted these ecosystems, emphasizing the need for sustainable management and conservation efforts.

2. Which of the following phenomena might have influenced the evolution of organisms? [2014-I]

  1. Continental drift
  2. Glacial cycles

 

Select the correct answer using the code given below.

Correct Answer: (c) Both 1 & 2
Solution:

Continental Drift has affected the evolution of animals, the world's geographical positions, and the world's climates.

The split of the original super landmass Pangea into Gondwanaland and Laurasia created new geographical/climatic regions.

The rearrangement and displacement of huge landmasses has helped create the diversity which we see in modern-day species.

The final stages of evolution of Genus Homo occur in the last 3 glacial cycles.

3. Consider the following statements [2015-I]

  1. The winds which blow between 30° N and 60° S latitudes throughout the year are known as westerlies.
  2. The moist air masses that cause winter rains in the North-Western region of India are part of westerlies.

 

Which of the statements given above is/are correct?

Correct Answer: (b) 2 only
Solution:

The Westerlies are prevailing winds from the west toward the east in the middle latitudes between 30 and 60 degrees latitude. They originate from the high-pressure areas in the horse latitudes and tend towards the poles and steer extra tropical cyclones in this general manner. The moist air masses that cause winter rains in the North-Western region of India are part of the westerlies.

Properties of Westerlies

  • The westerlies blow between 40° and 65° South latitudes.
  • These latitudes are referred to as the Roaring Forties, Furious Fifties, and Shrieking Sixties by sailors.
  • They blow towards the poles in the middle latitudes between 30 and 60 degrees latitude.
  • They develop in high-pressure regions in the horse latitudes and move towards the poles, and guide extratropical cyclones in this direction.
  • In the Northern Hemisphere, the winds are mostly from the southwest, while in the Southern Hemisphere, the winds are predominantly from the northwest.

4. Tides occur in the oceans and seas due to which among the following? [2015-I]

  1. Gravitational force of the Sun
  2. Gravitational force of the Moon
  3. Centrifugal force of the Earth

 

Select the correct answer using the code given below:

Correct Answer: (d) 1, 2 & 3
Solution:

Tides are the rise and fall of sea levels caused by the combined effects of gravitational forces exerted by the Moon, Sun, and rotation of the Earth.

  • Spring Tides:

  • Definition: These occur when the sun, moon, and Earth are aligned (during the new moon and full moon phases), causing the gravitational forces of the moon and the sun to combine, leading to higher high tides and lower low tides.
  • Effect: Spring tides produce the greatest tidal range.

  • Neap Tides:

  • Definition: These occur when the moon is at the first and third quarters of its phase, with the sun and moon’s gravitational forces working at right angles to each other. This results in lower high tides and higher low tides.
  • Effect: Neap tides produce the smallest tidal range.

5. "Each day is more or less the same, the morning is clear and bright with a sea breeze; as the Sun climbs high in the sky, heat mounts up, dark clouds form, then rain comes with thunder and lightning. But rain is soon over." Which of the following regions is described in the above passage? [2015-I]

Correct Answer: (b) Equatorial
Solution:The passage points out the equatorial region. The region around the equator is called the equatorial region and covers about 6% of the Earth.

About the Equatorial Climate

  • Equatorial climate, also known as tropical climate, is found near the equator, between the Tropic of Cancer and Tropic of Capricorn.
  • This climate is characterized by high temperatures and significant rainfall throughout the year.
  • Due to its consistent warmth, equatorial regions experience little seasonal variation, maintaining a nearly constant climate with temperatures typically ranging from 25–30°C (77–86°F).
  • The heavy rainfall, often exceeding 2000 mm annually, supports lush vegetation, making it ideal for dense rainforests.
  • These regions are home to extraordinary biodiversity, including unique plant and animal species.
  • The consistent climate fosters the growth of various tropical crops like bananas, cacao, and palm trees.
  • However, equatorial regions are also prone to extreme weather events such as thunderstorms and hurricanes.
  • Deforestation and human activities, like agriculture and urbanization, pose significant threats to the ecosystems in these areas.
  • Despite these challenges, equatorial climates play a crucial role in regulating the Earth’s climate and maintaining global biodiversity.

6. In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason? [2015-I]

Correct Answer: (b) Inter-Tropical Convergence Zone seldom occurs
Solution:The sea surface temperatures are too cold, the primary reasons that the South Atlantic Ocean gets few tropical cyclones are that the tropospheric vertical wind shear is too strong and there is typically no inter-tropical convergence zone (ITCZ) over the ocean. Without an ITCZ to provide synoptic vorticity and convergence (i.e., large-scale spin and thunderstorm activity) as well as having strong wind shear, it becomes very difficult to nearly impossible to have the genesis of tropical cyclones.

7. What explains the eastward flow of the equatorial counter-current? [2015-I]

Correct Answer: (b) Convergence of the two equatorial currents
Solution:The Earth's rotation on its axis explains the eastward flow of the equatorial counter-current. If the Earth had been rotating east to west, the piled-up water would have come down on the west side. Therefore, essentially it's the earth's rotation that explains the eastward flow of equatorial counter-current.
  • The equatorial countercurrent is a current phenomenon observed near the equator that is characterized by an eastward flow of oceanic water opposing and surrounded by the westward equatorial currents of the Atlantic, Pacific, and Indian oceans.
  • The Equatorial countercurrents are found mostly between latitudes 3° and 10° N, shifting south during the northern winter and north during the summer.
  • The trade winds which generally blow continuously on both sides from 10° and 30° N and S, push large amounts of water westward in the equatorial currents and rising sea levels in the west.
  • The higher western sea levels flow downslope to the east within the doldrums.
  • Equatorial Countercurrent which occurs in the Pacific Ocean is known as Pacific Equatorial Countercurrent.
  • The Pacific Equatorial Countercurrent is extremely powerful and can be detected all year.
  • Equatorial Countercurrent which occurs in the Atlantic Ocean is known as Pacific Equatorial Countercurrent.
  • The Atlantic Equatorial Countercurrent, often known as the Guinea Current, is strongest near the coast of Ghana (Africa).
  • Indian Ocean Countercurrent which occurs in the Atlantic Ocean is known as Pacific Equatorial Countercurrent.
  • The Indian Ocean's countercurrent only runs during the northern winter and only south of the equator.

8. Which of the following is/are tributary tributaries of Brahmaputra? [2016-I]

  1. Dibang
  2. Kameng
  3. Lohit

 

Select the correct answer using the code given below.

Correct Answer: (d) 1, 2 & 3 ​
Solution:

The Brahmaputra enters India in the state of Arunachal Pradesh from its original source Tibet and is joined by the Dibang River and the Lohit River at the head of the Assam Valley. It is joined in Sonitpur by the Kameng River (or Jia Bhoreli).

Brahmaputra’s main left bank tributaries are Dibang or Sikang and Lohit. The important right bank tributaries are Subansiri, Kameng, Manas, and Sankosh.

9. With reference to ‘Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? [2017-I]

  1. IOD phenomenon is characterized by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
  2. An IOD phenomenon can influence an El Nino's impact on the monsoon.

 

Select the correct answer using the code given below:

Correct Answer: (b) 2 only
Solution:
  • Indian Ocean Dipole (IOD) is an event in which the western Indian Ocean becomes alternately warmer and then colder than the eastern part of the Indian Ocean. So the first statement is wrong.
  • A positive IOD leads to greater monsoon rainfall and more active (above normal rainfall) monsoon days, while a negative IOD leads to less rainfall and more monsoon break days (no rainfall). So yes, IOD can influence El Niño's impact on the monsoon. Thus, the second statement is correct.

10. Consider the following statements [2018-I]

  1. The Barren Island volcano is an active volcano located in the Indian territory.
  2. Barren Island lies about 140 km east of Great Nicobar.
  3. The last time the Barren Island volcano erupted was in 1991 and it has remained inactive since then.

 

Which of the statements given above is/are correct?

Correct Answer: (a) 1 only
Solution:

Barren Island volcano became active again in March, 1991. A second phase of eruptions started in 1995. So it means the third statement is wrong, by elimination, we've the answer (a) only 1.

About Barren Island

  • It is a volcanic island located in the Andaman Sea.
  • Popularly known as a submarine emergent volcano, the island is a part of the Indian union territory of the Andaman and Nicobar Islands.
  • It lies about 138 kilometers northeast of the territory’s capital, Port Blair.
  • It lies above the subduction zone of India and Burmese plates.
  • It is the only active volcano in the Indian subcontinent. Also, along a chain of volcanoes from Sumatra to Myanmar, this is the only active volcano.
  • This island is about three kilometres in diameter and has a big crater of the volcano, about half a kilometer away from the shore.
  • It is a stratovolcano composed of lava, rock fragments, and volcanic ash.
  • It has erupted multiple times in recent history, with the most recent significant eruptions occurring in 2017.
  • It is inhabited by humans. Only a small population of goats, birds, bats, and rats are living under harsh conditions.