UPSC Prelims 2013 Question Paper
Explore the complete solved question paper for UPSC Prelims 2013 featuring 100 solved questions with bilingual (English & Hindi) explanations, official answer key, and subject weightage breakdown.
Consider the following statements: The Parliamentary Committee on Public Accounts:
- Consists of not more than 25 Members of the Lok Sabha
- Scrutinizes the appropriation and finance accounts of the Government
- Examines the report of the Comptroller and Auditor General of India
Which of the statements given above is/are correct?
Detailed Explanation:
❌ Statement 1 – Incorrect: The Public Accounts Committee (PAC) consists of 22 members (15 from Lok Sabha, 7 from Rajya Sabha), not 25. Members are elected annually by proportional representation using the single transferable vote.
✅ Statement 2 – Correct: PAC scrutinizes the Appropriation Accounts and Finance Accounts of the Government to ensure public funds are spent legally and for intended purposes.
✅ Statement 3 – Correct: PAC examines the audit reports of the Comptroller and Auditor General (CAG), who acts as the 'guide, philosopher, and friend' during PAC deliberations.
On the planet earth, most of the freshwater exists as ice caps and glaciers. Out of the remaining freshwater, the largest proportion
Detailed Explanation:
Of Earth's freshwater, over 68% exists as ice caps and glaciers.
Among the remaining freshwater, groundwater accounts for approximately 30%, making it the largest proportion after ice, while surface water (lakes and rivers) constitutes only 0.3% and atmospheric moisture and soil moisture represent even smaller fractions.
Which one of the following pairs is correctly matched? Geographical Feature -- Region
Detailed Explanation:
❌ Option A – Incorrect: The Abyssinian Plateau is located in Ethiopia (Horn of Africa), not Arabia.
✅ Option B – Correct: The Atlas Mountains stretch approximately 2,500 km through Morocco, Algeria, and Tunisia in North-Western Africa, with the highest peak Toubkal (4,167 m).
❌ Option C – Incorrect: The Guiana Highlands are located in northern South America (Venezuela, Guyana, Suriname, Brazil), not South-Western Africa.
❌ Option D – Incorrect: The Okavango Basin/Delta is in Botswana (Southern Africa), not Patagonia (which is in southern South America).
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Which of the following is/are the characteristic/ characteristics of Indian coal?
- High ash content
- Low sulphur content
- The low ash fusion temperature
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Indian coal has high ash content (35-45%), significantly higher than global average of ~15%, making it a defining characteristic.
✅ Statement 2 – Correct: Indian coal has low sulphur content (~0.5%), which is environmentally advantageous compared to many international coals.
❌ Statement 3 – Incorrect: Indian coal has high ash fusion temperature (~1,500°C), not low, making it unsuitable for entrained gasifiers in IGCC plants.
Variations in the length of daytime and nighttime from season to season are due to -
Detailed Explanation:
Seasonal variation in day and night length occurs due to the Earth's revolution around the Sun combined with its axial tilt of 23.5°.
The tilted axis causes different hemispheres to receive varying amounts of direct sunlight throughout the year – when the Northern Hemisphere is tilted toward the Sun (summer solstice), it experiences longer days; when tilted away (winter solstice), it experiences shorter days.
❌ Option 1 – Incorrect: Earth's rotation causes the daily cycle of day and night (24 hours), not seasonal variation in their length.
❌ Option 3 – Incorrect: Latitudinal position determines the magnitude of variation (polar regions experience extreme variation, equatorial regions minimal), but not the cause of seasonal changes.
❌ Option 4 – Incorrect: The elliptical orbit affects Earth-Sun distance but does not cause seasonal day-length variation; the tilt is the primary factor.
Consider the following statements:
- Natural gas occurs in the Gondwana beds.
- Mica occurs in abundance in Kodarma.
- Dharwars are famous for petroleum.
Which of the statements given above is/are correct?
Detailed Explanation:
✅ Statement 1 – Incorrect: Gondwana beds are primarily coal-bearing formations formed during the Carboniferous to Jurassic period; natural gas in India is found in tertiary sedimentary rocks of Assam, Gujarat, and offshore Mumbai High, not in Gondwana beds.
✅ Statement 2 – Correct: Koderma district in Jharkhand is known as the "Mica Capital of India" and has abundant deposits of high-quality ruby mica (muscovite).
✅ Statement 3 – Incorrect: Dharwar rocks are ancient Precambrian metamorphic formations in Karnataka rich in gold, iron ore, and manganese; petroleum occurs in younger sedimentary basins, not in metamorphic Dharwar formations.
The annual range of temperature in the interior of the continents is high as compared to coastal areas. What is/are the reason/reasons?
- Thermal difference between land and water
- Variation in altitude between continents and oceans
- Presence of strong winds in the interior
- Heavy rains in the interior as compared to coasts
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Thermal difference between land and water is the primary reason. Land has low specific heat capacity and heats/cools rapidly, while water has high specific heat capacity causing slow temperature changes. Coastal areas experience moderating effect from oceans, reducing annual temperature range, whereas continental interiors lack this maritime influence and show extreme seasonal variations.
❌ Statement 2 – Incorrect: Variation in altitude affects absolute temperature but does not explain the difference in annual range between coast and interior. Both regions have altitude variations.
❌ Statement 3 – Incorrect: Strong winds in the interior do not cause higher annual range; rather, coastal winds help moderate temperatures by bringing maritime influence.
❌ Statement 4 – Incorrect: Coastal areas typically receive more rainfall than continental interiors due to moisture from oceans. Rainfall does not explain higher temperature range inland.
Consider the following:
- Electromagnetic radiation
- Geothermal energy
- Gravitational force
- Plate Movements
- Rotation of the earth
- Revolution of the earth
Which of the above are responsible for bringing dynamic changes on the surface of the earth?
Detailed Explanation:
Electromagnetic radiation (solar energy) drives weather systems, ocean currents, and photosynthesis, creating dynamic surface changes.
Geothermal energy from Earth's interior fuels volcanism, hot springs, and geysers, altering landforms.
Gravitational force (Moon and Sun) generates ocean tides, causing coastal erosion and deposition.
Plate movements cause mountain building, earthquakes, volcanism, and continental drift, reshaping the Earth's surface.
Rotation of Earth creates Coriolis effect, influencing wind patterns, ocean currents, and cyclone formation.
Revolution of Earth around the Sun causes seasonal variations, affecting temperature, precipitation, and weathering rates.
All six forces work together to bring continuous dynamic changes to Earth's surface.
The most important fishing grounds of the world are found in the regions where:
Detailed Explanation:
The world's most productive fishing grounds are located where warm and cold oceanic currents converge. This mixing creates nutrient-rich waters and ideal conditions for phytoplankton growth, which forms the base of the marine food chain.
Grand Banks (Newfoundland): Cold Labrador Current meets warm Gulf Stream, creating one of the world's richest fishing zones.
North-West Pacific (Japan): Cold Oyashio Current meets warm Kuroshio Current, supporting highly productive fisheries.
Which of the following statements regarding laterite soils of India are correct?
- They are generally red in colour.
- They are rich in nitrogen and potash.
- They are well-developed in Rajasthan and UP.
- Tapioca and cashew nuts grow well on these soils.
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Laterite soils are characterized by their distinctive rusty-red colour due to high iron oxide content formed through leaching in tropical conditions.
❌ Statement 2 – Incorrect: Laterite soils are deficient in nitrogen, potash, potassium, phosphorus, and lime, though rich in iron and aluminium oxides; humus content is also very low.
❌ Statement 3 – Incorrect: Laterite soils are well-developed in high rainfall areas of Western Ghats, Eastern Ghats (Karnataka, Kerala, Tamil Nadu, Maharashtra), Odisha, Assam, and Meghalaya — not in semi-arid Rajasthan or UP.
✅ Statement 4 – Correct: Despite low fertility, tapioca, cashew nuts, tea, coffee, and rubber grow well on laterite soils with adequate fertilization and irrigation.
Which of the following is/are unique characteristic/characteristics of equatorial forests?
- Presence of tall, closely set trees with crowns forming a continuous canopy
- Coexistence of a large number of species
- Presence of numerous varieties of epiphytes
Select the correct answer using the code given below:
Detailed Explanation:
✅ Statement 1 – Correct: Equatorial forests have tall trees (40-60 m) growing close together with crowns forming a continuous dense canopy that blocks sunlight from reaching the forest floor.
✅ Statement 2 – Correct: These forests exhibit maximum biodiversity with coexistence of hundreds of tree species per hectare due to stable warm-wet climate and year-round growing season.
✅ Statement 3 – Correct: The high humidity and dense canopy structure support numerous epiphytes (orchids, ferns, mosses, bromeliads) that grow on trunks and branches without rooting in soil.
The Narmada river flows to the west, while most other large peninsular rivers flow to the east. Why?
- It occupies a linear rift valley.
- It flows between the Vindhyas and the Satpuras.
- The land slopes to the west from Central India.
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: The Narmada River flows through a linear rift valley formed by faulting and tectonic subsidence between the Vindhya Range (north) and Satpura Range (south). This east-west oriented rift structure directs the river's flow westward into the Arabian Sea, making it an exception among peninsular rivers.
❌ Statement 2 – Incorrect: While the Narmada does flow between the Vindhyas and Satpuras, merely being confined between two ranges does not explain the westward direction. Confinement alone could allow flow in either direction; it is the rift valley orientation that determines the westward flow.
❌ Statement 3 – Incorrect: The Peninsular Plateau has a general slope from west to east, which is why most peninsular rivers (Godavari, Krishna, Mahanadi) flow eastward to the Bay of Bengal. The Narmada's westward flow contradicts this regional slope and is explained by its structural control through the rift valley, not by land slope.
Consider the following crops
- Cotton
- Groundnut
- Rice
- Wheat
Which of these are Kharif crops?
Detailed Explanation:
✅ Statement 1 – Correct: Cotton is a major Kharif crop sown with the onset of monsoon (June-July) requiring high temperature and 210 frost-free days.
✅ Statement 2 – Correct: Groundnut is a Kharif oilseed crop grown during the monsoon season in India.
✅ Statement 3 – Correct: Rice is the principal Kharif crop requiring high temperature (above 25°C), high humidity, and annual rainfall above 100 cm.
❌ Statement 4 – Incorrect: Wheat is a Rabi crop sown in winter (October-December) and harvested in spring (April-June), requiring cool growing conditions.
“Climate is extreme, rainfall is scanty and the people used to be nomadic herders.” The above statement best describes which of the following regions?
Detailed Explanation:
Central Asian Steppe is characterized by extreme continental climate with summer temperatures up to 45°C and winter temperatures down to -50°C, scanty rainfall (250-500 mm annually), and was historically inhabited by nomadic herders like the Mongols and Kazakhs.
African Savannah has moderate tropical climate with 500-1500 mm rainfall; North American Prairie receives higher rainfall (500-900 mm) with less extreme temperatures; Siberian Tundra has permafrost and extremely cold climate unsuitable for extensive grazing and nomadic pastoralism.
With reference to food chains in ecosystems, consider the following statements :
- A food chain illustrates the order in which a chain of organisms feeds upon each other.
- Food chains are found within the populations of a species.
- A food chain illustrates the numbers of each organism which are eaten by others.
Which of the statements given above is/are correct?
Detailed Explanation:
✅ Statement 1 – Correct: A food chain illustrates the linear sequence in which organisms feed upon each other, showing the order of energy flow from producers → primary consumers → secondary consumers → tertiary consumers.
❌ Statement 2 – Incorrect: Food chains operate between different species, not within populations of a single species; they represent inter-species feeding relationships across different trophic levels.
❌ Statement 3 – Incorrect: A food chain shows only the feeding relationship and direction of energy flow, not the numbers or biomass of organisms; ecological pyramids illustrate numerical or biomass relationships.
In the grasslands, trees do not replace the grasses as a part of an ecological succession because of
Detailed Explanation:
Grasslands maintain themselves as climax communities due to two primary limiting factors: water scarcity and periodic fires.
Grasses have meristematic tissue at the base (not tips), allowing rapid regrowth after fire, while tree seedlings die in fires. Additionally, low annual precipitation (25-75 cm) and thin, dry soil prevent tree establishment, maintaining grasslands in a sub-climax stage.
Which of the following can be found as pollutants in the drinking water in some parts of India?
- Arsenic
- Sorbitol
- Fluoride
- Formaldehyde
- Uranium
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Arsenic (1) – Correct: Found in groundwater of West Bengal, Bihar, Uttar Pradesh, Assam, Jharkhand due to natural leaching from arsenic-bearing rocks; causes arsenicosis and skin lesions.
❌ Sorbitol (2) – Incorrect: A sugar alcohol used as artificial sweetener and humectant; not a naturally occurring groundwater pollutant in India.
✅ Fluoride (3) – Correct: Endemic in Rajasthan, Andhra Pradesh, Tamil Nadu, Gujarat, Haryana and other states; causes dental and skeletal fluorosis from geological sources.
❌ Formaldehyde (4) – Incorrect: An industrial chemical and disinfectant; not a common groundwater contaminant in Indian drinking water systems.
✅ Uranium (5) – Correct: Detected in groundwater of Punjab, Rajasthan, Haryana and parts of southern India; leaches from uranium-bearing granitic rocks.
With reference to the food chains in ecosystems, which of the following kinds of an organism is/are known as decomposer organism/organisms?
- Virus
- Fungi
- Bacteria
Select the correct answer using the codes given below.
Detailed Explanation:
Fungi and Bacteria are the primary decomposers in ecosystems that break down dead organic matter into simpler inorganic substances, recycling nutrients back into the environment.
Viruses are not decomposers—they are metabolically inactive outside host cells and function as obligate intracellular parasites that require living cells to replicate, playing no role in decomposition.
Photochemical smog is a resultant of the reaction among -
Detailed Explanation:
Photochemical smog is formed when nitrogen dioxide (NO₂), volatile organic compounds (VOCs), and oxygen react in the presence of sunlight to produce ozone (O₃) and peroxyacetyl nitrate (PAN).
Option 1 correctly identifies the resultant components (NO₂, O₃, and PAN) that characterize photochemical smog, which forms through photochemical reactions triggered by ultraviolet (UV) sunlight.
Acid rain is caused by the pollution of the environment by -
Detailed Explanation:
Acid rain is caused by sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) released from burning fossil fuels and vehicle emissions.
These gases react with water vapor, oxygen, and other atmospheric chemicals to form sulphuric acid (H₂SO₄) and nitric acid (HNO₃), which fall as acid rain.
UPSC Prelims 2013 Questions Paper - Subject-wise Question Distribution
UPSC Prelims 2013 Question Paper - FAQs & Analysis
Q1 How many total questions were asked in UPSC Prelims 2013?
Q2 What is the subject-wise question breakdown for UPSC Prelims 2013?
- Environment & Ecology: 21 questions (21%)
- Indian Economy: 20 questions (20%)
- Indian Polity: 17 questions (17%)
- Science & Technology: 11 questions (11%)
- World Geography: 9 questions (9%)
- Indian Art & Culture: 8 questions (8%)
- Modern History: 6 questions (6%)
- Indian Geography: 6 questions (6%)
- Ancient History: 2 questions (2%)