UPSC 2020 Prelims Questions with Answers

Explanation

Carbon nanotubes are cylindrical structures made of carbon atoms arranged in a hexagonal lattice. They possess exceptional strength, high electrical conductivity, and unique mechanical properties, making them promising materials for applications in electronics, materials science, and nanotechnology.

Statement 1 is correct: Carbon nanotubes (CNTs) have been widely researched for their role in drug delivery systems. Their unique hollow structure allows them to transport therapeutic molecules directly to targeted cells, improving treatment precision and effectiveness. Functionalization of CNTs enhances biocompatibility and minimizes toxicity.

Statement 2 is incorrect: Carbon nanotubes have applications in tissue engineering, including constructing artificial blood vessels. Their mechanical strength and ability to support cell growth make them useful for creating scaffolds that mimic natural capillaries, promoting tissue repair. However, UPSC in its official answer key has not given recognition to this development and marked statement 2 as incorrect.

Statement 3 is correct: Due to their exceptional electrical conductivity, carbon nanotubes are integral to the development of highly sensitive biochemical sensors. These sensors can detect specific biological molecules, contributing to advancements in diagnostics and monitoring technologies.

Statement 4 is correct: Multiple types of microbes, including bacteria and fungi, have the ability to degrade carbon nanotubes (CNTs). Thus carbon nanotubes are very much biodegradable in nature.

Explanation

Evolved LISA (eLISA) is a planned mission by the ESA for gravitational wave detection. It will detect minute distortions in space-time caused by gravitational waves. Lasers will shine between the spacecraft to measure changes in distance. Two "Daughter" spacecraft and a "Mother" spacecraft make up the eLISA mission. These will form a triangle orbit around the Sun. The two Daughter spacecraft will be joined to the Mother satellite, and the three satellites will form a precision interferometer by 1 million km long laser beams. Options (a), (b) and (c) are incorrect:

Voyager-2: A NASA spacecraft that studied Jupiter, Saturn, Uranus, and Neptune. It was not intended for gravitational wave detection. New Horizons: The first mission to explore Pluto and the Kuiper Belt, focused on planetary exploration rather than detecting gravitational waves. LISA Pathfinder: It was the precursor mission of eLISA that successfully demonstrated the technology required for a space based gravitational wave observatory.

Explanation

Statement 1 is correct: In India, food items make up a significant portion of the CPI, around 45%, reflecting the price changes consumers experience. In contrast, the WPI, which tracks wholesale prices, assigns a smaller share to food items, approximately 25-30%. The CPI measures the average change in prices paid by consumers for a basket of goods and services. Food is a significant component of household budgets, especially in developing economies, so it has a substantial weight in the CPI. The WPI, on the other hand, tracks the prices of goods at the wholesale level (i.e., prices received by producers or wholesalers).

Statement 2 is correct: The WPI focuses on measuring price changes in goods at the wholesale level and excludes services. While CPI includes both goods and services, such as healthcare, transportation, and education, which is a major difference between the two indices.

Statement 3 is incorrect: The RBI has not adopted the WPI as its key measure of inflation. The RBI uses the Consumer Price Index (CPI) as its primary gauge of inflation for monetary policy decisions. The CPI is considered a better indicator of the price pressures faced by consumers, which is what the RBI is most concerned about when setting interest rates.

Explanation

A Parliamentary System of Government is characterized by the executive (Government) being accountable to the legislature (Parliament). Its other key features generally include:

Collective Responsibility: The Council of Ministers, led by the Prime Minister, is collectively responsible to the Lok Sabha (Lower House in India). Motion of No Confidence: The government can be removed by the Parliament through a vote of no confidence. Executive from the Legislature: The Prime Minister and Ministers are drawn from the legislature and remain in office as long as they have its confidence.

Explanation

A constitutional government is a system in which the powers of the government are limited by a constitution. This ensures that government actions are guided by established laws rather than arbitrary decisions. The core idea of a constitutional government is limited government, where authority is regulated, checked, and balanced by a legal framework.

Explanation

Statement 1 is correct: In India, the important pulse crops grown in winter (rabi) are chickpea, lentil, lathyrus, field pea and kidney bean. However, green gram, black gram and cowpea are grown in both spring and rainy season. Black gram (Urad dal) can be cultivated in both kharif (monsoon) and rabi (winter) seasons in India, making it a versatile crop in the country’s agricultural cycle.

Statement 2 is incorrect: According to the Directorate of Economics and Statistics (DES), the share of pulse production in 2018-19 was as follows: Tur (15.34%), Gram (43.29%), Moong (Green gram, 10.04%), Urad (Black gram, 13.93%), Lentil (6.67%), and other pulses (10%). Green gram alone does not account for nearly half of India’s total pulse production.

Statement 3 is incorrect: Over the past three decades, both kharif pulses and rabi pulses have experienced increased production due to improved agricultural practices, increased area under cultivation, and better support for pulse farming.

Explanation

Option (a) is correct: Cotton is India’s most important fiber crop, accounting for about 25% of the world’s cotton production. Cotton growing condition requirements:

Temperature and climate: Cotton flourishes in a subtropical climate with optimal temperatures ranging from 21°C to 30°C. Rainfall: Cotton needs 50 to 100 cm of rainfall during its growing period, but excessive or waterlogged conditions can negatively affect its growth. Soil Type: Cotton grows best in light, well-drained, moisture-retaining soils, especially the black cotton soil of the Deccan Plateau, which has high moisture-retention capacity. Frost-Free Days: Requires at least 210 frost-free days and bright sunshine to complete its life cycle. Growing Season: It is a kharif crop and typically takes 6 to 8 months to mature Top Cotton Producing States: Gujarat > Maharashtra > Telangana > Andhra Pradesh > Rajasthan. Options (b), (c) and (d) are incorrect:

Jute: Requires high rainfall (150-200 cm) and humid weather, not subtropical conditions. Sugarcane: Requires higher rainfall (75-200 cm) and thrives mainly in tropical regions. Tea: Requires cool, humid conditions, heavy rainfall (150-300 cm), and acidic soils, unlike the drier conditions needed for cotton.

Explanation

In India, minerals are classified as major minerals and minor minerals under the Mines and Minerals (Development and Regulation) Act, 1957. Major minerals are those specified in the First Schedule of the Act and are under the regulatory control of the central government. Minor minerals are defined under Section 3(e) of the Act and are regulated by state governments.

Option (d) is correct: The following are Major minerals:

Chromite is an oxide mineral of chromium and iron and is the primary source for chromium. It is extensively used in metallurgy, refractory materials, and chemicals. Kyanite is a typically blue silicate mineral used in refractory and ceramic products. Sillimanite is an alumino-silicate mineral used in high-temperature ceramics and refractories. Bentonite is a type of clay formed from volcanic ash and is primarily used in drilling mud, binder, purifier, and absorbent applications. In India, bentonite is officially classified as a minor mineral.

Explanation

The Wildlife Protection Act, 1972 has six schedules. Schedule VI mandates, ‘no person is allowed to cultivate a specified plant mentioned in schedule 6, except with a licence granted by the Chief WildLife Warden’. The plants mentioned in the sixth schedule includes:

Beddomes Cycad Blue Vanda Kuth Ladies slipper orchids Pitcher plant Red Vanda

Explanation

Steel Slag, a by-product of steel making, is produced during the separation of the molten steel from impurities in steel-making furnaces. The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidi-fies upon cooling.

Statement 1 is correct: Steel slag is widely used as a base course material in road construction, providing a strong and durable foundation beneath asphalt roads, tracks, and paved surfaces. Its high strength, resistance to deformation, and excellent drainage properties enhance pavement longevity.

Statement 2 is correct: Steel slag can be used in the agricultural sector due to its ability to correct soil acidity. In fact, developed countries like Japan, the USA have taken the lead in making fertilisers using steel-making slag.

Statement 3 is correct: Additionally, it is utilized in the production of Portland slag cement (PSC), where it is blended with ordinary Portland cement to improve durability and resistance to chemical attacks. This not only enhances cement quality but also promotes sustainable construction by recycling industrial byproducts.