Science and Technology: UPSC Previous Year Questions (Prelims)
473 previous year UPSC Prelims Science and Technology questions are on this page, from 1996 to 2025, in 21 chapters. Biology: Zoology is the largest, followed by Miscellaneous (energy, vehicles and materials), Botany, Space and ICT. Recent papers lean on applied technology in the news, while older ones lean on school-level physics, chemistry and biology. Filter by chapter to revise one area at a time.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 61–70 of 473 questions
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UPSC 2020Science and Technology · Information and Communication Technology
Q61. In India, under cyber insurance for individuals, which of the following benefits are generally covered, in addition to payment for the loss of funds and other benefits? 1. Cost of restoration of the computer system in case of malware disrupting access to one’s computer 2. Cost of a new computer if some miscreant wilfully damages it, if proved so 3. Cost of hiring a specialized consultant to minimize the loss in case of cyber extortion 4. Cost of defence in the Court of Law if any third party files a suit Select the correct answer using the code given below:
Explanation
Statement 1 is correct: Cost of restoration of the computer system in case of malware disrupting access to one’s computer is generally covered under cyber insurance policies. If a malware attack disrupts access to your computer system the insurance can covers the expenses related to restoring the system to its original state.
Statement 2 is incorrect: Cyber insurance policies do not cover physical damage to hardware. They primarily focus on digital and financial losses. If a computer is physically damaged by a miscreant, it would fall under general insurance or property insurance rather than cyber insurance. These insurance policies are primarily focused on addressing losses arising from cybercrimes affecting data and software.
Statement 3 is correct: Cyber insurance often covers the cost of hiring cybersecurity experts, consultants, or negotiators to minimize financial and reputational losses in case of cyber extortion such as ransomware attacks.
Statement 4 is correct: Cyber insurance policies often provide coverage for legal defense costs if a third party initiates a lawsuit related to a cyber incident. This includes expenses such as attorney fees and other legal charges. Example: Bajaj Allianz’s policy covers defense costs arising from claims made by third parties against the insured individual.
Exam tip:
For S2, Cyber insurance primarily covers digital or cyber losses -- hacking, malware, phishing, extortion. Physical damage to hardware (e.g., breaking the computer) is usually covered under electronic equipment or home insurance, not cyber insurance. Hence likely false.
UPSC 2020Science and Technology · Information and Communication Technology
Q62. With reference to "Blockchain Technology" consider the following statements: 1. It is a public ledger that everyone can inspect but which no single user controls 2. The structure and design of blockchain is such that all the data in it is about crypto currency only. 3. Applications that depend on basic features of blockchain can be developed without anybody’s permission. Which of the statements given above is/are correct?
Explanation
Blockchain technology is a decentralized and secure system for recording and verifying transactions across multiple computers. It uses cryptography to link blocks of data together in a chain, making it difficult to alter or tamper with the information. This technology has applications in various fields, including finance, supply chain management, and healthcare.
Statement 1 is correct: Blockchain operates as a decentralized and distributed ledger, allowing all participants to view transactions without granting control to any single user. This transparency and lack of central authority are fundamental characteristics of blockchain technology.
Statement 2 is incorrect: While blockchain gained prominence through cryptocurrencies like Bitcoin, its applications extend far beyond digital currencies. Blockchain’s versatile structure supports various uses, including supply chain management, healthcare data management, and identity verification, among others.
Statement 3 is correct: Public blockchain platforms, such as Ethereum, enable developers to build decentralized applications (dApps) without requiring approval from a central authority. This open-access design promotes innovation and encourages widespread participation within the blockchain ecosystem.
Exam tip:
For S2, The phrase "all the data in crypto currency only" is too absolute and extreme to be true, hence likely false, eliminates options B and C.
UPSC 2020Science and Technology · Nanoscience and Nanotechnology
Q63. When reference to carbon nanotubes, consider the following statements: 1. They can be used as carriers of drugs and antigens in the human body. 2. They can be made into artificial blood capillaries for an injured part of the human body. 3. They can be used in biochemical sensors. 4. Carbon nanotubes are biodegradable. Which of the statements given above are correct?
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.
Exam tip:
For S2, The phrase can be made into artificial blood capillaries implies real-world medical application, not just lab potential. That’s an extreme generalization of a field still in early-stage trials. This is similar to wireless electricity transfer in Question 68, page 573. Hence more probably false.
UPSC 2020Science and Technology · Space and Space Technology
Q64. The experiment will employ a trio of spacecraft flying in formation in the shape of an equilateral triangle that has sides one million kilometers long, with lasers shining between the craft." The experiment in question refers to
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.
UPSC 2020Science and Technology · Nuclear Technology
Q65. In India, why are some nuclear reactors kept under "IAEA Safeguards" while others are not?
Explanation
IAEA safeguards apply to nuclear reactors using imported uranium as part of India’s international agreements. These safeguards ensure that the imported fuel is strictly used for civilian purposes and not diverted for military use. However, not all nuclear reactors in India are placed under IAEA safeguards. Reactors using domestic uranium are not subject to these safeguards allowing flexibility for strategic programs. By keeping reactors using domestic uranium outside IAEA safeguards, India maintains the flexibility to support its strategic programs without external oversight. As of recent data, out of India’s 22 operational reactors, 14 are under IAEA safeguards because they utilize imported fuel.
Additional insight:
Reactors Using Imported Uranium - Under IAEA Safeguards India imports uranium through civil nuclear cooperation agreements with countries like the U.S., Russia, and France. Reactors using imported uranium must be placed under IAEA safeguards to ensure peaceful usage. Example: Kudankulam Nuclear Power Plant (uses Russian-supplied fuel). Reactors Using Domestic Uranium - Not Under IAEA Safeguards India has natural uranium reserves, but they are insufficient to meet demand. Reactors using domestic uranium remain under sovereign control and are not necessarily under IAEA safeguards. Example: Tarapur (TAPS-1 & 2) and some PHWRs initially used domestic uranium and were not under safeguards.
UPSC 2020Science and Technology · Miscellaneous
Q66. Consider the following activities: 1. Spraying pesticides on a crop field 2. Inspecting the craters of active volcanoes 3. Collecting breath samples from spouting whales for DNA analysis. At the present level of technology, which of the above activities can be successfully carried out by using drones?
Explanation
A drone, technologically, is an unmanned aircraft.
They are formally known as unmanned aerial vehicles (UAVs). A drone is essentially a flying robot that can be remotely piloted or can fly on its own using software-controlled flight plans in embedded systems in conjunction with onboard sensors and GPS.
Statement 1 is correct: Modern agriculture has increasingly adopted drones for the application of pesticides and fertilizers. These drones offer precision in spraying, ensuring uniform coverage and reducing the exposure of farmers to harmful chemicals. For instance, a study published in Springer highlights that drones equipped with advanced sensors and high-resolution cameras can distinguish between healthy and infested crops, allowing for targeted pesticide application.
Statement 2 is correct: Drones equipped with visual and thermal cameras are utilized in geological studies to inspect active volcano craters. They can safely approach hazardous areas, capturing high-resolution images and collecting gas samples. Researchers from the German Research Centre for Geosciences (GFZ) successfully employed drones to study the active Santa Maria volcano in Guatemala.
Statement 3 is correct: Marine biologists have innovated methods to collect biological samples from whales using drones. By flying drones through the spouts of whales, researchers can gather respiratory droplets containing DNA, hormones, and microorganisms without disturbing the animals. This technique was employed in the Ocean Alliance’s SnotBot program.
UPSC 2020Science and Technology · Miscellaneous
Q67. Which of the following statements are correct regarding the general difference between plant and animal cells? 1. Plant cells have cellulose cell walls whilst animal cells do not. 2. Plant cells do not have plasma membranes unlike animal cells which do. 3. Mature plant cell has one large vacuole whilst an animal cell has many small vacuoles. Select the correct answer using the code given below:
Explanation
Statement 1 is correct: Both plants and animals contain eukaryotic cells, their cell structures are quite similar. The plasma membrane, nucleus, cytoplasm, ribosomes, and mitochondria in general make up each eukaryotic cell. The plant cell differs significantly from other cells in that it has a hard cell wall surrounding it. While the cells of other species are surrounded by a cell wall, cellulose and proteins are present in plant cells.
Statement 2 is incorrect: Both plant and animal cells have a plasma membrane that surrounds the cytoplasm and regulates the movement of substances in and out of the cell. The plasma membrane is essential for maintaining homeostasis and facilitating communication between the cell and its environment in both plant and animal cells.
Statement 3 is correct: A mature plant cell typically contains a single, large central vacuole, which can occupy up to 90% of the cell’s volume. This vacuole stores water, nutrients, and waste products and helps maintain turgor pressure, providing structural support to the plant. Animal cells often have multiple small vacuoles scattered throughout the cytoplasm. These vacuoles perform similar storage and waste-management functions but are smaller and less prominent than those in plant cells. Animal Cell Plant Cell
UPSC 2020Science and Technology · Miscellaneous
Q68. In the context of recent advances in human reproductive technology. "Pronuclear Transfer" is used for
Explanation
Pronuclear transfer is an advanced reproductive technique primarily utilized to prevent the transmission of mitochondrial diseases from mother to offspring. Mitochondrial diseases are genetic disorders caused by mutations in mitochondrial DNA (mtDNA), which is inherited exclusively from the mother. These disorders can lead to severe health issues, affecting organs with high energy demands, such as the brain, heart, and muscles.
UPSC 2020Science and Technology · Miscellaneous
Q69. With reference to solar water pumps, consider the following statements: 1. Solar power can be used for running surface pumps and not for submersible pumps. 2. Solar power can be used for running centrifugal pumps and not the ones with piston. Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: Solar power is capable of operating both surface and submersible pumps. Surface Pumps are installed above the water surface and are suitable for applications where water is drawn from shallow sources. They can be effectively powered by solar energy. Submersible pumps are designed to operate underwater. These pumps are ideal for deep wells or boreholes. Solar-powered submersible pumps are widely used for extracting water from significant depths.
Statement 2 is incorrect: Solar power can be utilized to run both centrifugal and piston (positive displacement) pumps. Centrifugal Pumps are commonly used in solar applications for higher flow rates with lower lift. They are efficient when adequate solar power is available. Piston Pumps also known as positive displacement pumps, piston pumps are suitable for applications requiring high lift with lower flow rates. Their ability to maintain efficiency under varying conditions makes them well-suited for solar-powered systems.
Exam tip:
Solar power is just a source of electricity. It can power any device that runs on electricity -- depending on how much power (wattage) you generate. Why would solar care about pump mechanism? It just supplies electricity. The motor and circuit handle the internal mechanics. Hence both statements are restrictive by saying "NOT"and hence likely false.
UPSC 2020Science and Technology · Miscellaneous
Q70. With reference to the current trends in the cultivation of sugarcane in India, consider the following statements: 1. A substantial saving in seed material is made when ‘bud chip settings’ are raised in a nursery and transplanted in the main field. 2. When direct planting of seeds is done, the germination percentage is better with single -budded setts as compared to setts with many buds. 3. If bad weather conditions prevail when seeds are directly planted, single - budded seeds have better survival as compared to large setts. 4. Sugarcane can be cultivated using settlings prepared from tissue culture. Which of the statements given above is/are correct?
Explanation
Tissue culture (TC) is the cultivation of plant cells, tissues, or organs on specially formulated nutrient media. Under the right conditions, an entire plant can be regenerated from a single cell. Commercial planting of sugarcane uses setts (cuttings that can form roots) at a rate of 6 to 8 tonnes per hectare, or around 10% of total production.
Statement 1 is correct: Due to its bulky attire and physical restrictions, the tissue culture method is becoming uneconomical. Planting excised axillary canestalk buds, sometimes referred to as budchips, would help reduce the mass and enhance the quality of the seed cane. After four to five weeks, healthy settlings are transplanted on a well-prepared field with a row spacing of 90 cm and a gap of 30 cm between each settling (small setts).
Statement 2 is incorrect: Due to moisture loss from the other cut end, the germination percentage of a single bud sett is extremely low. Numerous studies and trials demonstrate that the germination rate of 3 bud sets is higher than the setts having more or less than three buds. Additionally, even if the entire can stem is planted without being trimmed, only the top end will sprout, resulting in a poor germination percentage.
Statement 3 is incorrect: Under bad weather conditions, larger setts (multi-budded) generally have better survival rates compared to single-budded setts. This is because they store more nutrients and moisture, which helps them withstand adverse conditions better than single-budded setts.
Statement 4 is correct: The most crucial and labour-intensive step in sugarcane agriculture is planting. Supplying disease-free seed cane of current commercial types quickly is an innovative new technique, called tissue culture. It employs meristems to clone the mother plant. Tissue culture plants’ cane and sugar yields are comparable to those of plants grown using traditional methods.
Exam tip:
S2 and S3 seems counterintuitive. A sett with multiple buds has a higher chance that at least one will germi-nate. Single-budded setts are more vulnerable. Hence both are likely false. In bad weather, again, single buds are more fragile. Bigger setts might be physically more resilient and offer redundancy.
Answer key for these questions
Q
UPSC year
Correct answer
61
2020
(b) 1, 3 and 4 only
62
2020
(d) 1 and 3 only
63
2020
(c) 1, 3 and 4 only
64
2020
(d) Evolved LISA
65
2020
(b) Some use imported uranium and others use domestic supplies
66
2020
(d) 1, 2 and 3
67
2020
(c) 1 and 3 only
68
2020
(d) prevention of mitochondrial diseases in offspring
69
2020
(d) Neither 1 nor 2
70
2020
(c) 1 and 4 only
What UPSC has tested in Science and Technology
Recent questions are application-based: electric vehicles, quantum computing, monoclonal antibodies, CRISPR, gravitational waves and space missions.
Older questions test school science: buoyancy, scattering of light, atomic structure and common compounds.
In Physics and Chemistry, explanations that depend on formulas or equations are left out where the original text could not be shown reliably.
The 2025 paper’s Science and Technology questions covered EVs, UAVs, coal gasification, CL-20, Majorana 1, monoclonal antibodies, GAGAN and ISRO missions.
Frequently asked questions
How many previous year UPSC questions are there on Science and Technology?
This page covers 473 previous year UPSC Prelims GS Paper-I questions on Science and Technology, asked from 1996 to 2025. Each has the correct answer and an explanation.
Which Science and Technology chapters have the most questions?
Biology: Zoology has the most with 115 questions, then Miscellaneous with 68, Biology: Botany with 37, Space and Space Technology with 36 and Information and Communication Technology with 32.
How should I revise Science and Technology from these questions?
Take the technology chapters first, because recent papers favour them, then use the Physics, Chemistry and Biology chapters for basics. Each chapter page lists the facts UPSC has tested and has an answer key.
Why do some Chemistry and Physics questions look missing?
Questions whose explanations depend on chemical formulas or equations that could not be shown correctly were left out, rather than risk a wrong formula. The questions that remain have clear explanations in plain words.
