Geography: UPSC Previous Year Questions (Prelims)

Explanation

Tropical rainforests, also called equatorial forests, are found near the equator between the Tropics of Cancer and Capricorn. These forests thrive in areas with high temperatures and consistent rainfall, which support the rich and diverse vegetation.

Statement 1 is correct: This is a defining characteristic of tropical rainforests, also called equatorial forests. The trees are generally tall (often reaching 30-45 meters), and their crowns form a continuous canopy, which allows very little sunlight to reach the forest floor. The canopy helps in conserving moisture and maintaining the unique ecosystem.

Statement 2 is correct: Tropical rainforests are known for their high biodiversity, with a large number of species coexisting in close proximity. The climatic conditions (constant warmth and moisture) lead to intense ecological dynamics that promote coevolution, making these forests the most biodiverse terrestrial ecosystems on Earth.

Statement 3 is correct: Epiphytes, such as mosses, ferns, and orchids, are common in equatorial forests. These plants grow on other plants (usually trees) to reach sunlight, without drawing nutrients from the soil. Epiphytes are abundant in the tropics due to the high humidity and constant sunlight.

Explanation

The annual range of temperature refers to the difference between the highest and lowest temperatures over the course of a year. This range is typically higher in the interior of continents compared to coastal areas due to specific climatic factors.

Statement 1 is correct: Land heats and cools more rapidly than water due to its lower specific heat capacity. This leads to greater temperature extremes in continental interiors. In contrast, coastal areas experience moderate temperatures year-round be-cause water’s higher specific heat allows it to absorb and release heat more slowly, stabilizing the climate.

Statement 2 is incorrect: Altitude affects local temperature (higher altitudes are cooler), but it does not significantly influence the annual temperature range between coastal and interior regions. The question is about horizontal (coastal vs. interior) differences, not vertical (altitude) differences.

Statement 3 is incorrect: While winds affect the local temperature, strong winds do not have a direct relationship with the annual temperature range. Wind patterns influence the distribution of temperature but do not necessarily cause a high annual range in the interior of continents.

Statement 4 is incorrect: In fact, coastal areas usually receive more rainfall due to their proximity to large water bodies. Heavy rains tend to moderate temperatures by increasing humidity, which reduces temperature variations. Thus, this is not a factor in increasing the annual temperature range.

Explanation

The description of extreme climate, scanty rain-fall, and nomadic herding best fits the Central Asian Steppe Climate or Temperate Continental Climate or Temperate Grassland Climate:

Temperature: The continental climate of the Steppe regions is characterized by extreme temperature variations between summer and winter. Precipitation: The average rainfall is about 45 cm, but varies as per location from 25 cm to 75 cm. The heaviest rain in June and July (late spring and early summer). Lifestyle: Historically, the Central Asian Steppe was home to nomadic herders like the Kirghiz and Kazakhs, who relied on migratory animal grazing. However, nomadic lifestyles have largely declined due to modernization.

Explanation

Thunder is caused by lightning. When a lightning bolt travels through the air, it heats the air to an extremely high temperature (up to 30,000 Kelvin). This sudden heating causes the air to expand explosively, creating a shockwave that we hear as thunder. It is not caused by the meeting of clouds, the separation of clouds, or the upward movement of air and water particles.

Statement 1 is incorrect: Thunder is not caused by the meeting of clouds. Cumulonimbus clouds are indeed responsible for thunderstorms, but thunder itself results from the rapid heating and expansion of air due to lightning, not the merging of clouds.

Statement 2 is incorrect: Lightning occurs due to electrical dis-charge within or between clouds and the ground. Thunder results from the sudden expansion of air due to the intense heat of lightning, not from nimbus cloud separation.

Statement 3 is incorrect: While violent air and water particle movements occur within cumulonimbus clouds during a thunderstorm, they do not directly produce thunder. The updrafts and downdrafts determine storm intensity but are not responsible for the sound of thunder.

Explanation

Option (c) is correct: Regions where warm and cold ocean currents meet are highly productive fishing grounds due to:

Plankton Growth: Cold currents bring nutrient-rich deep water, while warm currents stabilize conditions, fostering plankton blooms, the base of the marine food chain. Fish Abundance: These regions attract fish feeding on plankton, creating rich fishing zones like Newfoundland (Labrador Current meets Gulf Stream), North Sea (Gulf Stream meets Arctic currents), and seas near Japan (Kuroshio meets Oyashio).

Explanation

Statement 1 is correct: The distinctive red colour is one of the key characteristics of laterite soils. It appears red due to the high concentration of iron oxides. In tropical climates, heavy rainfall causes intense leaching, washing away silica and other bases while leaving behind iron and aluminum oxides, which give the soil its distinctive red color.

Statement 2 incorrect: Laterite soils are poor in nitrogen, phosphorus, and potash (potassium). The intense leaching caused by heavy rainfall in tropical regions washes away these soluble nutrients.

Statement 3 is incorrect: Laterite soils are primarily found in the humid tropical regions of India, such as the Western Ghats, parts of Eastern Ghats, and some northeastern states. Rajasthan and Uttar Pradesh (UP) have a drier climate which is not suitable for the formation of laterite soils.

Statement 4 is correct: The agro-climatic conditions of laterite soils support the cultivation of crops such as tapioca, cashew nuts, groundnut, coffee, and rubber. These crops are well-adapted to the moisture-retaining and nutrient-poor nature of laterite soils.

Explanation

Statement 1 is incorrect: The Gondwana beds are primarily famous for containing coal reserves, with nearly 98% of India’s coal reserves found in them. They are not significant for natural gas reserves. Natural gas in India is more commonly associated with other formations such as sedimentary basins such as the Cambay Basin or the Krishna-Godavari Basin.

Statement 2 is correct: Kodarma in Jharkhand is a well-known region for mica production, which has been an important mineral in India’s mineral resources. Mica is found abundantly here and Kodarma is often referred to as the "mica capital" of India.

Statement 3 is incorrect: The Dharwar system of rocks is not known for petroleum production. The Dharwar rocks are particularly valuable for metallic minerals like high-grade iron ore, manganese, and copper. Petroleum is not found in the Dharwar rock system but in other formations like the Cambay Basin or the Rajasthan Basin.

Explanation

Factors of The Dynamic Changes of the Earth:

Electromagnetic radiation from the sun, particularly in the form of solar energy, drives atmospheric and surface processes such as weathering, erosion, and the water cycle. These processes contribute to the continuous reshaping of Earth’s surface. Geothermal energy originates from Earth’s internal heat, which fuels volcanic activity and drives plate tectonics. These internal processes lead to the formation of new landforms, mountain building, and seafloor spreading, all of which dynamically alter Earth’s surface. Gravity influences the movement of water, sediments, and tectonic plates. It plays a crucial role in processes like mass wasting (landslides), river flow, and glacial movement which contributes to the dynamic changes on Earth’s surface. The movement of tectonic plates leads to continental drift, mountain formation, earthquakes, and volcanic activity. Rotation of the Earth causes the Coriolis effect, which deflects moving air and water, influencing weather patterns, ocean currents, and thus affecting erosion and deposition. It also contributes to the tides. Revolution of the Earth around the sun, combined with its axial tilt, causes the seasons. Seasonal variations in temperature and precipitation influence weathering, erosion, and the activity of living organisms, all of which contribute to surface changes. Thus, all of the above are responsible for bringing dynamic changes on the surface of the earth. Since all the listed factors contribute to dynamic changes, the correct answer is option (d).

Explanation

Indian coal is predominantly of the bituminous to sub-bituminous variety, which accounts for over 80% of the non-coking coal reserves in India. Bituminous coal is widely used in India, particularly in power plants, but the high ash content requires effective ash handling and disposal systems.

Option 1 is correct: Indian coal is characterized by a high ash content, which refers to the non-combustible residue left after burning coal. This is a significant characteristic of coal in India, making it less efficient and more environmentally damaging when burned.

Option 2 is correct: Indian coal has a low sulphur content, which makes it relatively cleaner than coals from other regions that have higher sulfur levels. This reduces the emissions of harmful sulfur dioxide when the coal is burned.

Option 3 is incorrect: Indian coal typically has a high ash fusion temperature (about 1,500°C). The ash fusion temperature refers to the temperature at which the ash in coal begins to soften and fuse, and Indian coal is known for its high ash fusion temperature, making it more resistant to fusion during combustion.

Explanation

Cotton, Groundnut and Rice are Kharif Crops in India while wheat is a Rabi Crop.