12 previous year UPSC Prelims questions on Science and Technology in the UPSC 2023 Prelims. Choose an option to see the answer and explanation.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 1–10 of 12 questions
Metagenomics delves into the study of microbes within their native habitats. "Aerial metagenomics" entails collecting air samples from a specific setting to capture the genetic material (DNA) of various microorganisms, encompassing bacteria, viruses, fungi, and other microscopic life forms.
Microsatellite DNA, alternatively known as short tandem repeats (STRs), represents a genetic marker characterised by repetitive sequences of DNA. Highly polymorphic, microsatellites exhibit varying lengths attributed to discrepancies in the number of repeat units. By scrutinising the discrepancies in microsatellite DNA sequences within individuals or populations, scientists can evaluate genetic diversity, population structure, and evolutionary links both within species and across different species.
About the Wolbachia Method Wolbachia is a type of bacterium, that can be introduced into mosquitoes to diminish their capacity for transmitting diseases. Fig: Wolbachia method Wolbachia method is used to control the population of mosquitoes and thus helps in controlling viral diseases such as zika, dengue, and chikungunya spread by the mosquitoes. In this method, the male Aedes Aegypti mosquitoes with Wolbachia mate with wild female mosquitoes that do not have Wolbachia, the eggs will not hatch and thus leads to sterilisation.
Statement 1 is correct: Carbon fibre is a material consisting of very thin filaments of carbon atoms. Carbon fibers are fibers characterized by a carbon content of 90% or higher. The principal rationale behind the aerospace industry’s adoption of carbon fiber lies in the weight reduction it offers.
Statement 2 is incorrect: Carbon fibre is environmentally friendly and exhibits a longer life cycle. There are numerous technologies to recycle carbon fibres.
| Objects in space | Description |
|---|---|
| 1. Cepheids | Giant clouds of dust and gas in space |
| 2. Nebulae | Stars which brighten and dim periodically |
| 3. Pulsars | Neutron stars that are formed when massive stars run out of fuel and collapse |
Pair 1 is not correct: Cepheids, also known as Cepheid Variables, are stars that periodically brighten and dim. Due to their behaviour, these objects can function as cosmic indicators, extending their usefulness as yardsticks for distances up to several tens of millions of light-years away, owing to a consistent relationship between their brightness and other factors.
Pair 2 is not correct: A nebula is a very large cloud of gas and dust in outer space. A dead star’s explosion, such as a supernova, releases gas and dust, which in turn forms certain nebulae (more than one nebula). Other nebulae are places where brand-new stars are only starting to develop. It is for this reason that some nebulae are referred to as "star nurseries."
Pair 3 is correct: Pulsars are extremely compact, rapidly km (12 miles). They are virtually entirely made of neutrons that are formed when massive stars run out of fuel and collapse.
The term "Global Navigation Satellite System" (GNSS) encompasses any satellite network offering positioning, navigation, and timing (PNT) services either globally or within specific regions.The Quasi-Zenith Satellite System (QZSS) stands as a regional GNSS owned by the Government of Japan, aiming to bolster coverage in East Asia and Oceania while complementing GPS.
Statement 1 is not correct: Ballistic missiles are rocket-powered only during the initial (boost) phase of flight, following an arcing trajectory to the target after that. Ballistic missiles travel well outside earth’s atmosphere. In contrast, cruise missiles are jet-propelled at subsonic speeds throughout their journeys. Cruise missile flies within the earth’s atmosphere and uses jet engine technology.
Statement 2 is not correct: The Defence Research and Development Organisation (DRDO) of India developed the land-based intercontinental ballistic missile known as Agni-V. The BrahMos is a medium-range Ramjet Supersonic Cruise Missile that may be fired from a submarine, ship, aircraft, or land. The BrahMos is undoubtedly the world’s fastest supersonic cruise missile.
Content in both statements are interchanged. The term ballistic itself implies launch-arc-fall motion like a can-non shell -- this requires rocket power at least initially, not a jet engine. While, Cruise = implies long "drive-like" flight. Cruise ships, cruise control -- all constant-speed movement. Similarly in S2 too, hence both are likely false.
Green hydrogen is expected to play a prominent role in decarbonising heavy industries, including oil refineries, steel mills and fertiliser plants. Green hydrogen is produced by breaking down water in an electrolyser using only renewable energy, resulting in no carbon emissions. The production of fertiliser demands substantial energy, typically sourced from fossil fuels like natural gas. However, green hydrogen offers a promising alternative, serving either as an electricity source or directly utilised in the ammonia production process, which is crucial for manufacturing fertilizer. Oil refineries significantly contribute to greenhouse gas emissions through their energy-intensive operations and dependence on fossil fuels. However, integrating green hydrogen into refinery operations offers a viable solution to mitigate this impact by either substituting or complementing fossil fuels, thereby decreasing their carbon footprint. Hydrogen can play a vital role in refining procedures like hydrocracking and hydrotreating, enhancing fuel quality by eliminating impurities. The steel industry contributes substantially to worldwide carbon emissions. However, the adoption of green hydrogen presents an opportunity to address this issue by serving as a replacement for coal or coke as a reducing agent in the steelmaking process. Green hydrogen enables the Direct Reduced Iron (DRI) process, producing environmental -friendly or low-carbon steel. It can also support heat and electricity generation, further cutting emissions.
You can try, The "NOT" approach for all statements, this tests the improbability of negating a statement--if denying its impact seems highly unlikely, the statement is plausibly true.
Statement 1 is correct: Finely ground basalt rock is dispersed across agricultural lands to expedite the natural absorption of carbon dioxide from the atmosphere. This is known as enhanced rock weathering, where silicate minerals react with CO₂, forming stable carbonates and reducing atmospheric carbon, as well as improving the fertility of the soil.
Statement 2 is correct: This method, referred to as ocean alkalinity enhancement, encompasses the addition of lime (calcium oxide or calcium hydroxide) to the oceans to elevate their alkalinity. By doing so, it boosts the oceans’ ability to absorb and retain carbon dioxide from the atmosphere, thus assisting in carbon sequestration.
Statement 3 is correct: The process known as carbon capture and storage (CCS) involves capturing carbon dioxide emissions from industrial processes and storing them underground. Abandoned subterranean mines can be utilised as viable storage sites, where the captured carbon dioxide is injected into these locations as carbonated waters.
An accelerometer is an electromechanical device used to measure acceleration forces. These forces may be static like the continuous force of gravity or dynamic force to sense movement or vibrations.
Statement 1 is correct: Upon a collision, the crash sensor, typically an accelerometer, transmits a signal to the airbag control unit to deploy the airbags almost immediately.
Statement 2 is correct: Accelerometers in laptops protect hard drives from damage. If the laptop were to suddenly drop while in use, the accelerometer would detect the sudden free fall and immediately turn off the hard drive to avoid hitting the reading heads into the hard drive platter.
Statement 3 is correct: Accelerometer is used in smartphones as it detects the rotation of their display between portrait and landscape mode depending on the tilt of the phone.
| Q | UPSC year | Correct answer |
|---|---|---|
| 1 | 2023 | (a) Collecting DNA samples from air in a habitat at one go |
| 2 | 2023 | (a) Studying the evolutionary relationships among various species of fauna |
| 3 | 2023 | (a) Controlling the viral diseases spread by mosquitoes |
| 4 | 2023 | (a) 1 only |
| 5 | 2023 | (a) Only one |
| 6 | 2023 | (d) Japan |
| 7 | 2023 | (d) Neither 1 nor 2 |
| 8 | 2023 | (c) All three |
| 9 | 2023 | (c) All three |
| 10 | 2023 | (c) All three |
This page covers 12 previous year UPSC Prelims GS Paper-I questions on Science and Technology in the UPSC 2023 Prelims, asked from 1996 to 2025. Each has the correct answer and an explanation.
Attempt each question first, then open the answer and read the explanation for every option. Repeat by chapter, and track which statements UPSC reuses across years. Previous year questions show the exam pattern and difficulty level.
Questions on Science and Technology in the UPSC 2023 Prelims are available for 30 years, from 1996 to 2025. Use the Year filter to practise a single paper.
