Physical Geography (UPSC) (Part-I)

Total Questions: 50

41. Temperature and rainfall of a meteorological station are given below: [2001]

MonthTemperature (°C)Rainfall (cm)
J9.412.2
F10.69.1
M11.77.9
A12.22.5
M13.31.0
J13.90.3
J13.9-
A14.4-
S15.60.8
O15.02.5
N13.36.1
D10.611.7

Average temperature: 12.8°C
Average rainfall: 54.9 cm per annum

Identify the region having the above climatic patterns from amongst the following:

Correct Answer: (a) Mediterranean region
Solution:The region will be Mediterranean according to the characteristics described by the climatic patterns. Mediterranean climate is characterised by hot, dry summers and warm, wet winters.
• The Mediterranean climate is characterized by hot, dry summers and mild, wet winters. This climate is primarily found around the Mediterranean Basin, but also occurs in regions like southern California, central Chile, parts of South Africa, and southwestern Australia.
• It is influenced by the subtropical high-pressure system, resulting in dry summers and wet winters.
• During the summer months, high-pressure systems dominate, bringing clear skies, high temperatures, and minimal rainfall. In contrast, the winter season is marked by lower pressure, which brings cooler temperatures and more precipitation.
• These seasonal variations contribute to the development of unique vegetation, such as olive trees, vineyards, and shrubs like chaparral and maquis.
• Mediterranean climates support diverse ecosystems, including rich biodiversity, fertile agricultural land, and scenic landscapes.
• However, due to its arid summers and seasonal rainfall, regions with a Mediterranean climate are susceptible to drought and wildfire risks, making sustainable land management essential for maintaining ecological balance.

42. Assertion (A): During the neap tides, the high tide is lower and the low tide is higher than usual. [2001]

Reason (R): The neap tide, unlike the spring tide, occurs on the new moon instead of on the full moon.

Correct Answer: (c) A is true but R is false
Solution:The sun, the earth and the moon come in the position of quadrature (form-a right angle) on seventh and eighth day of every fortnight of a month and thus the tide producing forces of the sun and the moon works in opposite direction, causing low tide. This is lower in height than the normal tide and is called neap tide. But the spring tide occurs during full moon and are called high tides.
• Tides are the regular, predictable rise and fall of ocean water levels along coastlines, caused by the gravitational forces exerted by the moon and the sun on Earth’s oceans, combined with Earth’s rotation.
• The gravitational pull of the moon is the primary force driving tides, while the sun also contributes, though to a lesser extent. When the moon’s gravity pulls on Earth’s oceans, it creates a bulge of water, causing the high tide.
• The areas perpendicular to the bulge experience low tide, as the water is pulled away. The Earth’s rotation causes different locations to pass through these high and low tide phases throughout the day.
• Tides occur in cycles, typically every 12 hours and 25 minutes, creating two high and two low tides daily (semi-diurnal tide).
• In some regions, tides may be diurnal (one high and one low tide per day). Tides are crucial for coastal ecosystems, navigation, and marine life.

43. Sun's halo is produced by the refraction of light in: [2002]

Correct Answer: (c) ice crystals in Cirrus clouds
Solution:

Sun halo is an optical phenomenon that occurs due to sunlight refracting millions of hexagonal ice crystals suspended in the atmosphere.

How it is formed?
When white light passes through unique hexagonal ice crystals found in upper-level cirrus clouds, causing the halo to have colours.
The clouds contain millions of tiny ice crystals, which refract and split the light to give an impression of a circular rainbow ring.
The crystals have to be oriented and positioned just so with respect to your eye, for the halo to appear.
Light undergoes two refractions as it passes through the ice crystals and the bending that occurs depends on the ice crystal’s diameter.
The two refractions bend the light by 22 degrees from its original point, producing a ring of light around the Sun or the Moon.

44. Consider the following statements: [2002]

  1. Ocean currents are slow-surface movement of water in the ocean.
  2. Ocean currents assist in maintaining the Earth's heat balance.
  3. Ocean currents are set in motion primarily by prevailing winds.
  4. Ocean currents are affected by the configuration of the ocean.

Which of these statements are correct?

Correct Answer: (b) 2, 3 and 4
Solution:Ocean currents are not slow most of the time and can be subsurface current also. So, statement '1' is wrong. But '2', '3' and '4' statements are correct.
Ocean currents are persistent and predictable flows of ocean water mass. These are driven by factors like wind, density gradients, Earth’s rotation, and landmasses that cause and influence their speed, direction and behaviour. These horizontal and vertical movements of ocean water are part of a large complex system that regulates heat transfer, shapes biodiversity patterns, and plays a vital role in Earth’s climate dynamics. Primarily, there are two types of ocean currents - warm and cold currents. These currents arrange themselves in such a way that they form the world’s major and minor oceanic gyres.

45. Consider the following statements: [2002]

  1. In equatorial regions, the year is divided into four main seasons
  2. In Mediterranean region, summer months receives more rain.   
  3. In China type climate; rainfall occurs throughout the year.
  4.  Tropical highlands exhibit vertical zonation of different climates.
Correct Answer: (d) 3 & 4
Solution:

• Equatorial regions experience consistently high temperatures and abundant rainfall throughout the year, with little to no distinction between seasons.
• Mediterranean climates are characterized by hot, dry summers and mild, wet winters, so rainfall is concentrated in the cooler winter months.
• China-type climates receive rainfall year-round, though often with a peak in summer due to monsoon influences and convective storms.
• As altitude increases in tropical highlands, temperatures decrease, creating distinct climate zones (like "hot land," "temperate land," and "cold land") at different elevations, a phenomenon known as vertical zonation.

46. Consider the following ecosystems: [2002]

  1. Taiga
  2.  Tropical Evergreen
  3. Tropical Deciduous
  4.  Tundra

The correct sequence in decreasing order of the Albedo values of these ecosystems is:

Correct Answer: (b) 4, 1, 2, 3
Solution:According to ecosystem, the maximum albedo would be of Tundra, then Taiga, then Tropical Deciduous then Tropical ever green.
Albedo refers to the fraction of solar energy that is short-wave radiation reflected from the Earth back into space. It is expressed in percentage or as a decimal ranging from 0, for no reflection, to 1, for total reflection. High albedo surfaces include ice and snow, which basically reflect most of the incident sunlight, while low albedo surfaces, such as forests and oceans, are major absorbers of sunlight. Albedo helps scientists understand how surface and atmospheric changes ramify the dynamics of energy on the planet.

47. Assertion (A): 60° 65° latitudes in both the hemispheres have a low pressure belt instead of high pressure. [2002]

Reason (R): The low pressure areas are permanent over oceans rather than on land.   

 

Correct Answer: (b) Both A and R are true but R is NOT a correct explanation of A
Solution:Sub-polar low pressure is located between 60-65° latitude in both hemisphere. Low pressure is produced in this area, because the surface air spreads outward from this zone due to rotation of earth.

The sub-polar low pressure-belt is more developed and regular in the Southern hemisphere, white it is Fragmented in the Northern hemisphere due to the dominant presence of water in the former.

48. Assertion (A): The surface winds spiral inwards upon the centre of the cyclone. [2002]

Reason (R): Air descends in the centre of the cyclone.

Correct Answer: (a) Both A and R are true and R is the correct explanation of A
Solution:The centre of cyclone is the eye of cyclone which is extreme high pressure area, surrounded by low pressure area. The surface winds spiral inwards upon the centre of cyclone due to low pressure developed around eye.

Thus Ass is correct.

Where as there is high pressure inside the eye so the air desends there thus maintaining circulation of air. R is also correct.

49. Consider the following climatic and geographical phenomena: [2002]

  1. Condensation
  2. High temperature and humidity
  3. Orography
  4. Vertical wind

Thunder cloud development is due to which of these phenomena?

Correct Answer: (d) 1, 2, 3 & 4
Solution:The thunder clouds develop by the above climatic and geographic phenomena. High temperature and humidity causes the wind to rise vertically up and due to orography and pressure of mountains these winds get condensed and form cumulonimbus clouds or thunder clouds.
• Thunderstorms arise when layers of warm, moist air rise in a large, swift updraft to cooler regions of the atmosphere.
• There, the moisture contained in the updraft condenses to form towering cumulonimbus clouds and, eventually, precipitation.
• Columns of cooled air then sink earthward, striking the ground with strong downdrafts and horizontal winds.
• At the same time, electrical charges accumulate on cloud particles (water droplets and ice).
• Lightning discharges occur when the accumulated electric charge becomes sufficiently large.
• Lightning heats the air it passes through so intensely and quickly that shock waves are produced. These shock waves are heard as claps and rolls of thunder.
• On occasion, severe thunderstorms are accompanied by swirling vortices of air that become concentrated and powerful enough to form tornadoes.

50. For short-term climatic predictions, which one of the following events, detected in the last decade, is associated with occasional weak monsoon rains in the Indian sub-continent? [2002]

Correct Answer: (c) El Nino. and Southern Oscillations
Solution:El Nino and Southern oscillation are the reasons associted with occasional weak monsoon rains in Indian sub-continent. El Nino is a warm oceanic current of pacific ocean, near Peru coast of S. America.
• El-Nino, combined with the Walker Circulation or Southern Oscillation, is called El-Nino Southern Oscillation (ENSO), as they are closely linked.
• The system encompasses both oceanic and atmospheric phenomena, featuring warm currents off the coast of Peru in the Eastern Pacific that influence weather patterns globally, including in India.
• El Niño represents an extension of the warm equatorial current, which temporarily displaces the cold Peruvian or Humboldt current.
• This shift leads to a temperature increase of approximately 10°C in the waters off the Peruvian coast. This results in:
  ○ The distortion of equatorial atmospheric circulation.
  ○ Irregularities in the evaporation of seawater.
  ○ Reduction in the number of plankton further reduces the number of fish in the sea.