UPSC CSE Prelims
World Geography Previous Year Questions (PYQs)
Solved Previous Year Questions (PYQs) for World Geography in UPSC CSE Prelims in English & Hindi Medium.
Chapter Breakdown: Scroll →
Consider the following factors:
- Rotation of the Earth
- Air pressure and wind
- The density of ocean water
- Revolution of the Earth
Which of the above factors influence the ocean currents?
Detailed Explanation:
✅ Statement 1 – Correct: Rotation of the Earth causes the Coriolis effect, which deflects ocean currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
✅ Statement 2 – Correct: Air pressure and wind generate wind-driven currents by exerting friction on the ocean surface; prevailing winds like Trade Winds and Westerlies drive major surface currents.
✅ Statement 3 – Correct: Density of ocean water, determined by temperature and salinity, drives thermohaline circulation (deep ocean currents).
❌ Statement 4 – Incorrect: Revolution of the Earth (orbit around the Sun) causes seasonal changes but does not directly influence ocean currents.
Normally, the temperature decreases with the increase in height from the Earth’s surface, because
- the atmosphere can be heated upwards only from the Earth’s surface
- there is more moisture in the upper atmosphere
- the air is less dense in the upper atmosphere
Select the correct answer using the codes given below:
Detailed Explanation:
✅ Statement 1 – Correct: The atmosphere is transparent to incoming solar radiation but is primarily heated from below by long-wave terrestrial radiation emitted from Earth's surface, making lower layers warmer.
❌ Statement 2 – Incorrect: Water vapor and moisture are concentrated in the lower atmosphere (troposphere), not the upper atmosphere, which is significantly drier.
✅ Statement 3 – Correct: At higher altitudes, air pressure decreases making air less dense; rising air expands and undergoes adiabatic cooling, and thinner air has lower capacity to absorb and retain heat.
Which one of the following is the characteristic climate of the Tropical Savannah Region?
Detailed Explanation:
Tropical Savannah Climate (Köppen classification Aw) is characterized by a distinct wet season (summer months with heavy rainfall) and a distinct dry season (winter months with little to no rainfall).
This climate is found in regions like the African Savannah, Brazilian Cerrado, and parts of India, where the seasonal migration of ITCZ (Inter-Tropical Convergence Zone) causes alternating wet and dry periods.
🧐 Not Sure What to Study Next?
Get a personalised study plan based on your goals, time and revision needs.
Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
Detailed Explanation:
Carbon, Hydrogen, and Nitrogen are the primary elements responsible for the origin of life on Earth.
Carbon forms the backbone of all organic molecules, while Hydrogen and Nitrogen are essential for creating amino acids, nucleic acids (DNA/RNA), and proteins — the fundamental building blocks of life.
Electrically charged particles from space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth?
Detailed Explanation:
Earth's magnetic field (magnetosphere) acts as a protective shield, deflecting charged particles (solar wind, cosmic rays) toward the polar regions.
When these particles collide with atmospheric gases near the poles, they create auroras (Aurora Borealis and Aurora Australis), preventing direct surface exposure that would harm living organisms.