UPSC CSE Prelims Questions

With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements:

1. PFAS are found to be widespread in drinking water, food, and food packaging materials.
2. PFAS are not easily degraded in the environment.
3. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies.

Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (d) 1, 2 and 3

Explanation:
All three statements are correct:

• PFAS are indeed widespread in drinking water, food, and food packaging materials.
• They are known for their persistence and are not easily degraded in the environment.
• Persistent exposure can lead to bioaccumulation in animal bodies, including humans.
  Possible Sources: Environmental science and toxicology reports on PFAS.

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?

(a) Amazon Basin
(b) Congo Basin
(c) Kikori Basin
(d) Rio de la Plata Basin

Correct Answer: (b) Congo Basin

Explanation:
The Congo Basin is known to have the world’s largest tropical peatland, which contains significant amounts of carbon. Its destruction could release large quantities of carbon into the atmosphere, contributing to climate change.
Possible Sources: Environmental studies and scientific reports on tropical peatlands.

On June 21 every year, which of the following latitude(s) experience(s) a sunlight of more than 12 hours?

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

Select the correct answer using the code given below:

(a) 1 only
(b) 2 only
(c) 3 and 4
(d) 2 and 4

Correct Answer: (d) 2 and 4

Explanation:

• On June 21, the Tropic of Cancer experiences the longest day of the year (summer solstice in the Northern Hemisphere), with more than 12 hours of sunlight.
• The Arctic Circle also experiences continuous daylight (midnight sun) on this date, resulting in more than 12 hours of sunlight.
• The Equator experiences approximately 12 hours of daylight year-round, and the Tropic of Capricorn experiences shorter days on this date.
  Possible Sources: Geography and astronomy textbooks.

With reference to “Coriolis force”, which of the following statements is/are correct?

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:

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer: (c) Both 1 and 2

Explanation:

• Statement 1 is correct because the Coriolis force increases with an increase in wind velocity.
• Statement 2 is correct because the Coriolis force is maximum at the poles and absent at the equator.
  Possible Sources: Physics and meteorology textbooks.

Consider the following description:

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?

(a) Equatorial climate
(b) China type climate
(c) Humid subtropical climate
(d) Marine west coast climate

Correct Answer: (d) Marine west coast climate

Explanation:

• The Marine West Coast climate is characterized by low annual and daily temperature ranges, precipitation throughout the year, and precipitation levels between 50 cm – 250 cm.
  Possible Sources: Climatology textbooks and climate classification references.

With reference to “water vapour”, which of the following statements is/are correct?

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:

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Correct Answer: (a) 1 only

Explanation:

• Statement 1 is correct because water vapour is a gas and its concentration decreases with altitude.
• Statement 2 is incorrect because the percentage of water vapour is not maximum at the poles; it is generally higher in tropical and equatorial regions.
  Possible Sources: Meteorology and atmospheric science textbooks.