UnderStand UPSC
Conquer with Confidence.

Answer- (a)

Explanation:

• Direct Sources of information:
  • Mining is an important direct source to know about the interior of the earth.
  • Volcanic eruption forms another source of obtaining direct information.
  • As and when the molten material (magma) is thrown onto the surface of the earth, during volcanic eruption it becomes available for laboratory analysis.
• Indirect Sources of information:
  • Meteors are an important indirect source. The material from meteors, though similar to Earth's in composition and structure, does not originate from the Earth's interior. These solid bodies are made of materials like or akin to those found on our planet.
  • The other indirect sources include gravitation, magnetic field, and seismic activity.
• Hence option (a) is the correct answer.
  

Answer- (a)

Explanation:

• Statement 1 is not correct: Relative humidity is the percentage of moisture present in the atmosphere as compared to its full capacity at a given temperature.
  • With the change of air temperature, the capacity to retain moisture increases or decreases and the relative humidity is also affected accordingly. It is greater over the oceans and least over the continents.
• Statement 2 is not correct: Absolute humidity is the actual amount of the water vapour present in the atmosphere. It is the weight of water vapour per unit volume of air and is expressed in terms of grams per cubic metre.
  • The ability of the air to hold water vapour depends entirely on its temperature. The absolute humidity differs from place to place on the surface of the earth.
• Statement 3 is correct: Dew point is the point at which saturation occurs in a given sample of air.
  • The air containing moisture to its full capacity at a given temperature is said to be saturated. It means that the air at the given temperature is incapable of holding any additional amount of moisture at that stage.

Answer: (d)

Explanation:

• Pair 1 is not correct: Munroe Island, also known as Munrothuruthu, is a picturesque and tranquil island located in the Kollam district of Kerala. It is located at the confluence of Ashtamudi Lake and the Kallada River.

• Pair 2 is not correct: Bhavani island is located on the Krishna river in the state of Andhra Pradesh. It is surrounded by Mangroves.

• Pair 3 is not correct: Sagar Island, also known as Ganga Sagar or Sagardwip is located in the Ganges delta, lying on the continental shelf of Bay of Bengal.
  • Sagar Island is a religious place for Hindus, where pilgrims celebrate Makar Sankranti festival, in honour of the Sun. It is located in the state of West Bengal.

Answer- (d)

Explanation:

• Statement 1 is correct: The retreating southwest monsoon season is marked by clear skies and rise in temperature. The land is still moist.
  • Due to the conditions of high temperature and humidity, the weather becomes rather oppressive. This is commonly known as the ‘October heat’.
• Statement 2 is correct: The weather in the retreating monsoon is dry in north India but it is associated with rain in the eastern part of the Peninsula. October and November are the rainiest months of the year in the eastern part of the Peninsula.

• Statement 3 is correct: The widespread rain in this season is associated with the passage of cyclonic depressions which originate over the Andaman Sea and manage to cross the eastern coast of the southern Peninsula.
  • A bulk of the rainfall of the Coromandel coast is derived from these depressions and cyclones. Such cyclonic storms are less frequent in the Arabian Sea.

Answer- (b)

Explanation:

• About the Western Disturbances: These are extratropical storms which bring rainfall and snowfall in the hills of north India.
  • They are upper-level synoptic-scale systems embedded in the subtropical westerly jet stream (STWJ).
• Statement 1 is correct: They form in the Mediterranean region.

• Statement 2 is correct: They travel eastward to northern Bangladesh and south-eastern Nepal.

• Statement 3 is not correct: It is a non-monsoonal precipitation pattern that induces low pressure systems in the lower layers of the atmosphere. This, ultimately, causes rainfall in the plains and snowfall in the mountains.