Physical Geography (UPSC) (Part-III)

Total Questions: 44

31. Consider the following statements [2023-I]

Statement-I: The temperature contrast between continents and oceans is greater during summer than in winter.
Statement-II: The specific heat of water is more than that of the land surface.

Which one of the following is correct in respect of the above statements?

Correct Answer: (d) Statement-I is incorrect but Statement-II is correct
Solution:

Statement 1 is incorrect: This statement is incorrect as the temperature contrast between the continents and oceans is more during the winter rather than summer.

Statement 2 is correct: This statement is also true. Specific heat is the amount of heat energy required to raise the temperature of a substance by a certain amount. Water has a relatively high specific heat compared to land surfaces. This means that it takes a larger amount of heat energy to raise the temperature of water compared to an equal mass of land surface material by the same amount. The high specific heat of water is due to its molecular structure and the presence of hydrogen bonding, which allows water to absorb and store a significant amount of heat energy.

32. Consider the following statements: [2023-I]

  1. In a seismograph, P waves are recorded earlier than S waves.
  2. In P waves, the individual particles vibrate to and fro in the direction of waves propagation whereas in S waves, the particles vibrate up and down at right angles to the direction of wave propagation.

Which of the statements given above is/are correct?

Correct Answer: (c) Both 1 and 2
Solution:P waves are compressional waves, which means that the individual particles vibrate to and fro in the direction of wave propagation. S waves are shear waves, which means that the particles vibrate up and down at right angles to the direction of wave propagation. P waves travel faster than S waves, so they are recorded earlier on a seismograph.

Earthquake waves

These are of 2 types – body waves and surface waves

Body waves:

  • Generated due to the release of energy at the focus and move in all directions travelling through the body of the earth. Hence, the name – body waves.
  • Travel only through the interior of the earth.
  • Faster than surface waves.
  • There are 2 types of body waves: P– primary waves and S–secondary waves.
  • P waves travel through gaseous, liquid and solid materials whereas S waves travel only through solid materials.

Surface Waves:

  • When the body waves interact with surface rocks, a new set of waves is generated called surface waves.
  • These waves move along the earth’s surface.
  • Surface waves are transverse waves in which particle movement is perpendicular to the wave propagation. Hence, they create crests and troughs in the material through which they pass.
  • They are the most damaging waves.
  • 2 common surface waves are Love waves and Rayleigh waves.

33. With reference to "water vapour", which of the following statements is/are correct? [2024-I]

  1. It is a gas, the amount of which decreases with altitude.
  2. Its percentage is maximum at the poles.

 

Select the answer using the code given below:

Correct Answer: (a) 1 only
Solution:
  • Water vapor is a gas, and its amount decreases with altitude.
  • The amount of water vapor generally decreases with altitude. This is because most of the water vapor originates from evaporation at the Earth’s surface, especially from oceans, seas, lakes, and other water bodies.
  • As you move higher in the atmosphere, the temperature decreases, and the capacity of air to hold water vapor also decreases.
  • The percentage of water vapor is not maximum at the poles; it is minimum there.
  • Water Vapor Concentration: The concentration of water vapor is typically higher in warmer regions near the equator, where evaporation rates are highest due to higher temperatures. Conversely, polar regions, which are much colder, have lower evaporation rates and thus lower concentrations of water vapor.
  • Maximum Percentage: The percentage of water vapor is not maximum at the poles; it is actually minimum due to the cold temperatures and limited evaporation.

34. Consider the following description: [2024-I]

  1. Annual and daily range of temperatures is low
  2. Precipitation occurs throughout the year.
  3.  Precipitation varies between 50 cm - 250 cm.
    What is this type of climate?
Correct Answer: (d) Marine West coast climate
Solution:Marine west coast climate is located poleward from the Mediterranean climate on the west coast of the continents. The main areas are: Northwestern Europe, west coast of North America, north of California, southern Chile, southeastern Australia and New Zealand. Due to marine influence, the temperature is moderate and in winter, it is warmer than for its latitude. The mean temperature in summer months ranges from 15°-20°C and in winter 4°-10°C. The annual and daily ranges of temperature are small. Precipitation occurs throughout the year. Precipitation varies greatly from 50-250cm. Hence correct answer is (d).

35. With reference to "Coriolis" force, which of the following statements is/are correct? [2024-I]

  1. It increases with increase in wind velocity.
  2. It is maximum at the poles and is absent at the equator.

 

Select the answer using the code given below:

Correct Answer: (c) Both 1 and 2
Solution:The rotation of the earth about its axis affects the direction of the wind. This force is called the Coriolis force. It deflects the wind to the right direction in the northern hemisphere and to the left in the southern hemisphere. The deflection is more when the wind velocity is high. The Coriolis force is directly proportional to the angle of latitude. It is maximum at the poles and is absent at the equator. Thus both statements are correct.

36. On June 21 every year, which of the following latitude(s) experience(s) a sunlight of more than 12 hours? [2024-I]

  1. Equator
  2. Tropic of Cancer
  3. Tropic of Capricorn
  4. Arctic Circle

Select the correct answer using the code given below:

Correct Answer: (d) 2 and 4
Solution:On 21st June, the Northern Hemisphere is tilted towards the sun. The rays of the sun fall directly on the Tropic of Cancer. As a result, these areas receive more heat. Sunlight of more than 12 hours is received at tropic of cancer. The North Pole is inclined towards the sun and the places beyond the Arctic Circle experience continuous daylight for about six months. Since a large portion of the Northern Hemisphere is getting light from the sun, it is summer in the regions north of the equator. The longest day and the shortest night at these places occur on 21st June. Thus, Option 2 and 4 are correct. Table 9.1: Length of the Day in Hours and Minutes on Winter and Summer Solstices in the Northern Hemisphere.
Latitude0°20°40°60°90°
December 2212h 00m10h 48m9h 8m5h 33m0
June 2112 h13h 12m14h 52m

18h 27m6 months 

37. One of the following regions has the world's largest tropical peatland, which holds about three years' worth of global carbon emissions from fossil fuels; and the possible destruction of which can exert a detrimental effect on the global climate. Which one of the following denotes that region? [2024-I]

Correct Answer: (b) Congo Basin
Solution:The Congo Basin is home to the world's largest tropical peatlands. The peat swamp forest of the Congo Basin stores around 29 billion tons of carbon - approximately equivalent to three years' worth of global greenhouse gas emissions - while the Basin as a whole absorbs nearly 1.5 billion tons of carbon dioxide a year. The Basin stretches across six countries-Cameroon, Central African Republic, Democratic Republic of the Congo, Congo, Equatorial Guinea and Gabon. The Congo Basin is one of the world's last regions that absorbs more carbon than it emits. Its possible destruction can have detrimental effect on the global climate. Thus, the correct answer is (b).

38. Consider the following statements: [2024-I]

Statement-I: The atmosphere is heated more by incoming solar radiation than by terrestrial radiation.

Statement-II: Carbon dioxide and other greenhouse gases in the atmosphere are good absorbers of long-wave radiation.

 

Which one of the following is correct in respect of the above statements?

Correct Answer: (d) Statement-I is incorrect, but Statement-II is correct
Solution:Consider that the isolation received at the top of the atmosphere is 100 per cent. While passing through the atmosphere some amount of energy is reflected, scattered and absorbed. Only the remaining part reaches the earth's surface. Roughly 35 units are reflected back to space even before reaching the earth's surface. Of these, 27 units are reflected back from the top of the clouds and 2 units from the snow and ice-covered areas of the earth. The reflected amount of radiation is called the albedo of the earth. The remaining 65 units are absorbed, 14 units within the atmosphere and 51 units by the earth's surface. The earth radiates back 51 units in the form of terrestrial radiation. Of these, 17 units are radiated to space directly and the remaining 34 units are absorbed by the atmosphere. Thus, the atmosphere is heated more by terrestrial radiation than by incoming solar radiation. Hence, Statement I is incorrect. The long wave radiation is absorbed by atmospheric gases particularly by carbon dioxide and the other greenhouse gases as they are good absorbers of long wave radiation. Thus, Statement II is correct.

39. Consider the following statements: [2024-I]

Statement-I: Thickness of the troposphere at the equator is much greater as compared to poles.

Statement-II: At the equator, heat is transported to great heights by strong convectional currents.

 

Which one of the following is correct in respect of the above statements?

Correct Answer: (a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
Solution:The thickness of the troposphere varies with latitude. It is thickest at the equator and thinnest at the poles. This variation is due to the differences in temperature and, consequently, the density of the air at different latitudes. Warm air is less dense and causes the troposphere to expand, making it thicker at the equator. Thus, Statement 1 is correct. At the equator, the intense solar heating causes strong convectional currents. These currents transport heat to great heights, contributing to the greater thickness of the troposphere in this region. Thus, Statement II is correct. The strong convectional currents at the equator are the primary reason for the increased thickness of the troposphere compared to the poles. Hence correct answer is (a).

40. Consider the following: [2024-I]

  1. Pyroclastic debris
  2. Ash and dust
  3. Nitrogen compounds
  4. Sulphur compounds

How many of the above are products of volcanic eruptions?

Correct Answer: (d) All four
Solution:A volcano is a site where gases, ash, and molten rock, known as lava, are expelled onto the Earth's surface. The substances that emerge include lava flows, pyroclastic debris, volcanic bombs, ash, dust, and gases like nitrogen compounds, sulfur compounds, and small quantities of chlorine, hydrogen, and argon. Hence correct answer is (d).

About Volcanism

  • Volcanism is a term describing geological processes under which the magma, gases, and volcanic materials are released from the Earth’s interior to the surface.
  • They are chiefly driven by the movement of tectonic plates and happen at divergent boundaries, convergent zones, and hot spots. In an eruption, magma appears as lava, which cools and solidifies to form igneous rocks.
  • Volcanoes, being the surface expressions of volcanism, come in several forms: shield volcanoes, stratovolcanoes, and cinder cones, with each having its own typical lava composition and eruption style.
  • Volcanic activity is explosive, carrying ash, pyroclastic flows, and gases, or it can be effusive, characterized by the steady outpouring of lava.
  • Although in popular connotation, volcanism bears destruction—damaging property, taking lives, and influencing climates—there are many benefits too.
  • It matures soils, provides geothermal energy, and continues to mold the Earth.
  • The study of volcanism helps geologists in terms of predicting eruptions, understanding the processes within Earth, and reducing hazards caused by volcanoes so that people can be better prepared and resilient.