IT, Computers & Emerging Tech — UPSC Prelims Science & Environment previous year questions

Statement 1 is correct. An LLM gives a probability to each possible next word and chooses from the likeliest words.
Statement 2 is correct. An LLM is trained by an optimisation method that reduces its prediction errors, called loss.
Statement 3 is wrong. LLMs learn from human text, so they can repeat the biases in that text. Their outputs are not unbiased.
So 1 and 2 only.
Remember: training data bias is the main source of bias in AI models.

Source: MeitY and NITI Aayog documents on Responsible AI; standard machine-learning texts

Statement 1 is correct. The National Quantum Mission aims to build intermediate-scale quantum computers with 50 to 1000 physical qubits. A qubit is the basic unit of quantum information.
Statement 2 is correct. The Mission sets up four Thematic Hubs (T-Hubs). They cover quantum computing, communication, sensing and metrology, and materials and devices.
So both statements are correct.
Remember: the Mission was approved in 2023 for 2023-24 to 2030-31 under the Department of Science and Technology.

Source: Department of Science and Technology, National Quantum Mission (2023)

Statement 1 is wrong. The three Sutras of the AI Impact Summit 2026 were People, Planet and Progress. 'Planning' is not one of them.
Statement 2 is wrong. The Charter for Democratic Diffusion of AI is a voluntary framework. It is not binding.
Statement 3 is correct. The New Delhi Declaration was built around seven Chakras (pillars). These include Access for Social Empowerment, AI for Science and Secure and Trusted AI.
So only 3.
Remember: the Summit was held in New Delhi in February 2026, and earlier AI summits were at Bletchley Park, Seoul and Paris.

Source: MeitY and PIB releases on the India AI Impact Summit 2026

Statement 1 is correct. DHRUV64 is the third chip made under the DIR-V Programme. The programme aims to enable microprocessor design in India.
Statement 2 is correct. DHRUV64 is India's first home-grown 1.0 GHz, 64-bit, dual-core microprocessor.
So both statements are correct.
Remember: DIR-V is the Digital India RISC-V programme, and it builds on the open RISC-V design.

Source: MeitY and C-DAC releases on DIR-V and DHRUV64

Statement 1 is correct. Blockchain records can be shown to the right stakeholders without risk of change.
Statement 2 is correct. Full copies of the ledger are stored on many computers in the network and are kept in sync within seconds.
Statement 3 is wrong. A consortium blockchain is run by a group of organisations and has controlled access. The mix of public and private features describes a hybrid blockchain.
Statement 4 is correct. Cryptographic algorithms make recorded and accepted data practically impossible to alter or delete.
So 1, 2 and 4.
Remember: blockchain is a distributed, tamper-resistant ledger.

Source: MeitY National Strategy on Blockchain (2021); NITI Aayog blockchain paper

Statement I is correct. Microsoft's Majorana 1 chip uses topological qubits. It is expected to enable quantum computing at scale.
Statement II is incorrect. Microsoft introduced the Majorana 1 chip in February 2025. Amazon Web Services did not.
Statement III is correct. Machine learning is the wider field. Deep learning uses multi-layer neural networks and is a subset of it.
So only I and III are correct.
Remember: Amazon's quantum chip is called Ocelot. Google's is called Willow.

Source: Microsoft announcement of the Majorana 1 quantum chip (February 2025); NCERT-level definition of machine learning

Statement I is correct. The Paris AI Action Summit of February 2025 was co-chaired by France and India. It followed the Bletchley Park Summit (2023) and the Seoul Summit (2024).
Statement II is incorrect. The US and the UK did not sign the Paris declaration on inclusive and sustainable AI. India did sign it.
So only Statement I is correct.
Remember: At Paris, India was announced as host of the next AI summit.

Source: Ministry of External Affairs and PIB on the AI Action Summit, Paris (February 2025)

The metaverse is a shared network of 3D virtual worlds. Many users can enter at the same time. They can own and trade virtual items such as land and avatars' goods.
Big data analytics studies large data sets. Cryptography is the science of secure communication. 'Virtual matrix' is not an accepted technical term for this idea.
Remember: ownership of virtual items in the metaverse is often tracked with blockchain tokens.

Source: Standard references on the metaverse (Ministry of Electronics and IT technology notes)

Statement 1 is correct. Carbon fibres are light and strong. They are used in aircraft and car parts.
Statement 2 is incorrect. Carbon fibre waste can be recycled by processes such as pyrolysis. The recycled fibre is used again.
Remember: Carbon fibre composites are costly to recycle but not impossible.

Source: UPSC CSE Prelims 2023 question(key a)

An accelerometer is a sensor that measures acceleration and tilt.
Action 1 needs it. A sudden deceleration in a crash triggers the airbag.
Action 2 needs it. Free fall is sensed so the drive head can be parked.
Action 3 needs it. The tilt of the phone is sensed to rotate the screen.
So all three need an accelerometer.
Remember: Gyroscopes measure rotation. Accelerometers measure acceleration.

Source: UPSC CSE Prelims 2023; NCERT Class XI Physics, Ch. 3 and 5 (basic motion)

Statement 1 is correct. SaaS products allow limited customisation of the interface and data fields.
Statement 2 is correct. SaaS is delivered over the internet, so users can open it on mobile devices.
Statement 3 is correct. Web email services run as software hosted by the provider. They are SaaS.
Remember: SaaS, PaaS and IaaS are the three cloud service models.

Source: NIST definition of cloud computing (SP 800-145)

Short-range devices work over a small area, usually a few metres to a few hundred metres.
Closed-circuit television uses cables or short radio links within a premises. RFID works over a few metres. A wireless LAN covers a building.
So all three are treated as short-range technologies.
Remember: Bluetooth and NFC are other short-range technologies.

Source: Department of Telecommunications / ETSI definition of short-range devices

A qubit is the basic unit of information in a quantum computer. Unlike a normal bit, it can be 0, 1 or a combination of both at once.
The other fields use different units. Cloud services and wireless technologies do not use qubits.
Remember: India's National Quantum Mission was approved in 2023.

Source: National Quantum Mission, Department of Science and Technology; NCERT Class XII Physics

All four platforms are built on open source technology.
Aarogya Setu was developed on open source technology and its code was released publicly.
CoWIN is built on open source components.
DigiLocker is built on open source technology under the Government of India open source approach.
DIKSHA is built on Sunbird, an open source digital building block.
So no platform can be left out, and every option with fewer than four items is incomplete.
Remember: Sunbird is the open source base of DIKSHA.

Source: MeitY, Policy on Adoption of Open Source Software for Government of India; Sunbird (sunbird.org)

Statement 1 is correct. Web 3.0 uses decentralised systems, so users keep ownership of their own data.
Statement 2 is correct. Social networks can run on a blockchain, where no single company holds the data.
Statement 3 is correct. Web 3.0 platforms are governed collectively by users, often through tokens or decentralised autonomous organisations.
In Web 2.0, large corporations own the platforms and the data.
Remember: Web 3.0 means a decentralised web built on blockchain.

Source: Standard technology literature on Web 3.0 and blockchain; MeitY National Blockchain Strategy

Statement 1 is correct. VLC works in the visible light band of about 375 to 780 nm.
Statement 2 is incorrect. VLC is short-range, because light does not pass through walls and weakens over distance.
Statement 3 is correct. VLC offers higher data rates than Bluetooth.
Statement 4 is correct. VLC uses light, not radio waves, so it causes no electromagnetic interference.
Remember: Li-Fi is a form of VLC.

Source: IEEE 802.15.7 standard on Visible Light Communication; standard physics references

AI can optimise machine use and so cut electricity consumption in industry (item 1).
AI helps in diagnosing disease from scans and reports (item 3).
AI performs text-to-speech conversion (item 4).
AI cannot do wireless transmission of electrical energy (item 5). That is a matter of physics and engineering.
The official key did not count the creation of meaningful stories and songs (item 2) as effective at that time.
Remember: Official key for this question is option (b).
Update (2026): Generative AI now writes stories and songs, but the exam answer stands.

Source: NITI Aayog, National Strategy for Artificial Intelligence (2018)

Statement 1 is correct. A public blockchain is an open ledger that many computers hold together. No single user controls it.
Statement 2 is incorrect. Blockchain can store any data, such as land records and supply chain details. It is not limited to cryptocurrency.
Statement 3 is correct. On open blockchains, anyone can build applications without seeking permission.
Remember: Cryptocurrency is only one use of blockchain.

Source: MeitY, National Strategy on Blockchain (2021)

Statement 1 is incorrect. AR adds computer images to the real world. It does not shut the world out.
Statement 2 is incorrect. Projecting computer images onto real surroundings describes AR, not VR.
Statement 3 is correct. AR works through a phone or PC camera while the user stays in the real world.
Statement 4 is correct. VR creates a fully simulated world and blocks out the real one.
Remember: AR adds to reality. VR replaces reality.

Source: Standard IT references on AR and VR

Pair 1 is incorrect. The Belle II experiment studies particle physics at a Japanese facility. It is not about artificial intelligence.
Pair 2 is correct. Blockchain is the technology behind digital currencies such as Bitcoin.
Pair 3 is incorrect. CRISPR-Cas9 is a gene editing tool and belongs to biotechnology.
So only pair 2 is correct.
Remember: Belle II is at KEK, Japan, and studies B mesons.

Source: UPSC CSE Prelims 2018 question(key b)