UPSC Prelims 2026
Science & Technology Previous Year Questions (PYQs)
Explore 19 solved UPSC Prelims 2026 Science & Technology questions with detailed step-by-step bilingual solutions, option analysis, and answer keys.
Which of the following statements about DHRUV64 is/are correct ?
- It is the third chip fabricated under the DIR-V Programme with an overall aim to enable the creation of microprocessors for India.
- It is India's first homegrown 1.0 GHz, 64-bit dual-core microprocessor.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 — Correct. DHRUV64 is the third chip fabricated under the Digital India RISC-V (DIR-V) Programme, in the following sequence:
| Order | Chip |
|---|---|
| 1st | THEJAS32 |
| 2nd | THEJAS64 |
| 3rd | DHRUV64 |
The DIR-V Programme aims to build an indigenous portfolio of RISC-V-based microprocessors to reduce India's dependence on imported chips and foreign intellectual property.
Statement 2 — Correct. DHRUV64 is India's first homegrown 1.0 GHz, 64-bit dual-core microprocessor, developed by C-DAC under the Ministry of Electronics and Information Technology (MeitY). It is built on the open-source RISC-V instruction set architecture, which ensures:
- No proprietary licensing fees
- Technological sovereignty for India
Key Facts to Remember:
- Programme: DIR-V (Digital India RISC-V)
- Developer: C-DAC under MeitY
- Architecture: Open-source RISC-V
- Significance: 3rd chip, 1st 64-bit dual-core at 1.0 GHz
The Bureau of Indian Standard (BIS) recently introduced a national standard to test and assess bomb disposal system. Which of the following statements with regard to this system is/are correct ?
- The new standard is known as IS 19445 : 2025.
- It will improve interoperability of equipment across agencies.
- It was developed by TBRL, DRDO in collaboration with the 30th Central Scientific Research Institute, Russia.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 — Correct. In December 2025, BIS notified India's first dedicated national standard for bomb disposal systems, officially designated as IS 19445:2025.
Statement 2 — Correct. The standard establishes comprehensive guidelines for evaluating bomb disposal equipment — including bomb blankets, baskets, and inhibitors — against blast loads and splinter effects. A key objective is to bring uniformity in testing and procurement, thereby improving safety, reliability, and interoperability across agencies such as Armed Forces, CAPFs, NSG, and State Police.
Statement 3 — Incorrect. The standard was developed indigenously by BIS at the request of the Ministry of Home Affairs (MHA) and DRDO's Terminal Ballistic Research Laboratory (TBRL). There is no collaboration with any Russian entity. In fact, the standard was specifically created to reduce reliance on foreign norms, as existing international standards were either restricted in access or misaligned with Indian operational realities.
Key Point: IS 19445:2025 is a landmark step in indigenisation of defence standards — developed entirely within India by BIS + DRDO/TBRL, not in collaboration with any foreign agency.
X', born in the UK, was conferred the Nobel Prize in 2025. He was a professor in an American university when this prize was announced. Identify 'X' :
Detailed Explanation:
John Clarke is the correct answer:
- Born: Cambridge, United Kingdom ✓
- Prize: 2025 Nobel Prize in Physics — for the discovery of macroscopic quantum mechanical tunneling in an electric circuit
- Affiliation at time of award: Professor Emeritus, University of California, Berkeley (American university) ✓
Why others are wrong:
| Option | Person | Born | University | Why Wrong |
|---|---|---|---|---|
| 1 | Michel H. Devoret | France | Yale / UC Santa Barbara (USA) | Not born in UK |
| 2 | Richard Robson | Yorkshire, UK | University of Melbourne (Australia) | Not American university |
| 4 | Joel Mokyr | Netherlands | Northwestern University (USA) | Not born in UK |
Key Logic: Only John Clarke satisfies both conditions — born in UK AND professor at an American university.
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Consider the following statements with regard to involvement of private entities in India's space programme :
- The Indian National Space Promotion and Authorisation Centre (IN-SPACe) is an autonomous agency formed to facilitate participation of private entities.
- Agnikul Cosmos launched the world's first flight using 3D-printed rocket engine.
- Skyroot Aerospace has developed liquid fuel for GSLV.
Which of the statements given above is/are correct ?
Detailed Explanation:
Statement 1 — Correct. IN-SPACe was established in 2020 as an autonomous, single-window nodal agency under the Department of Space (DOS). It acts as a bridge between ISRO and private players to promote, authorize, and facilitate private sector participation in India's space sector.
Statement 2 — Correct. In May 2024, Chennai-based startup Agnikul Cosmos successfully launched the Agnibaan SOrTeD suborbital rocket from its private launchpad at Sriharikota — marking the world's first flight powered by a single-piece, fully 3D-printed rocket engine (semi-cryogenic engine named Agnilet).
Statement 3 — Incorrect. Skyroot Aerospace develops its own independent launch vehicles (the Vikram series) and engines. It does NOT develop fuel or engines for GSLV. The GSLV is an ISRO-owned heavy-lift rocket whose liquid and cryogenic stages are developed entirely in-house by ISRO via the Liquid Propulsion Systems Centre (LPSC).
Key Trick: Statement 3 mixes two separate private players — Agnikul (3D engine) and Skyroot (Vikram rockets) — and falsely links Skyroot to GSLV.
Which of the following statements with regard to stealth technology is/are correct ?
- Stealth objects have a very small radar cross-section and are coated with Radar Absorbing Material.
- Stealth objects can be detected using specific frequencies.
- Stealth objects are coated with metamaterials to increase the scattering of electromagnetic radiation.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 — Correct. The primary goal of stealth technology is to minimize an object's Radar Cross-Section (RCS). This is achieved through:
- Geometric shaping — to deflect radar waves away from the source
- Radar Absorbing Materials (RAM) — which absorb electromagnetic radar energy and dissipate it as heat
Statement 2 — Correct. Stealth objects are not completely invisible. RAM coatings are optimized to defeat high-frequency radars (X-band). However, low-frequency radars (VHF/UHF bands) can detect stealth objects as their longer wavelengths resonate with the aircraft's physical dimensions — though they lack resolution required for a missile lock.
Statement 3 — Incorrect. Metamaterials in stealth applications are used to decrease/eliminate radar scattering — NOT increase it. They work by:
- Perfectly absorbing electromagnetic radiation, OR
- Bending and redirecting waves around the object (electromagnetic cloaking)
Increasing scattering would make the object more visible — defeating the very purpose of stealth.
Key Trick: Statement 3 reverses the function of metamaterials — a classic UPSC trap of replacing a correct word with its opposite.
Which of the following statements with regard to genetic medicine is/are correct ?
- Genetic medicines correct/compensate for the faulty genes responsible for disease.
- Engineered viruses and lipid nanoparticles are used as carriers of the genetic medicine.
- Genetic medicines alter the entire DNA sequence.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 — Correct. Genetic medicines (gene therapy and gene editing) treat diseases at their root cause by introducing, removing, or changing genetic material to correct or compensate for faulty/missing genes responsible for a disease.
Statement 2 — Correct. Genetic material cannot be injected directly — it requires a vector (carrier):
| Vector Type | Example | Mechanism |
|---|---|---|
| Engineered Viruses | AAV, Lentiviruses | Modified to remove disease-causing properties; deliver therapeutic genes |
| Lipid Nanoparticles (LNPs) | mRNA/CRISPR delivery | Encapsulate genetic payload in protective fat layer |
Statement 3 — Incorrect. Genetic medicines do NOT alter the entire DNA sequence. The human genome has ~3 billion base pairs and 20,000+ genes. Gene therapies are highly precise — targeting only specific localized sequences or single genes while leaving the vast majority of native DNA completely unchanged.
Key Trick: Statement 3 uses the word "entire" — a classic UPSC exaggeration trap. Precision, not wholesale alteration, is the hallmark of genetic medicine.
Which one of the following pairs of semiconductor plants in India and their locations is not correctly matched?
| Semiconductor Plant | Location |
|---|---|
| (a) CG Power and Industrial Solutions Pvt. Ltd. in partnership with Renesas Electronics and STARS Microelectronics | Gujarat |
| (b) Tata Semiconductor Assembly and Test Pvt. Ltd. | Assam |
| (c) HCL-Foxconn Joint Venture India Chip Ltd. | Madhya Pradesh |
| (d) SicSem Pvt. Ltd. | Odisha |
Detailed Explanation:
Option A — Correctly Matched ✓ CG Power (in partnership with Renesas Electronics & STARS Microelectronics) is setting up an OSAT facility in Sanand, Gujarat.
Option B — Correctly Matched ✓ Tata Semiconductor Assembly and Test Pvt. Ltd. (TSAT) is establishing a greenfield semiconductor assembly and test facility in Jagiroad, Assam — a major industrial investment for Northeast India.
Option C — Incorrectly Matched ✗ The HCL-Foxconn Joint Venture (India Chip Pvt. Ltd.) OSAT facility is being set up in Jewar, Uttar Pradesh (Yamuna Expressway Industrial Development Authority region) — NOT Madhya Pradesh. It will manufacture display driver chips.
Option D — Correctly Matched ✓ SicSem Pvt. Ltd. is establishing a Silicon Carbide (SiC) semiconductor plant in Bhubaneswar, Odisha — India's first commercial compound semiconductor fab.
Quick Memory Table:
| Company | Correct Location |
|---|---|
| CG Power + Renesas + STARS | Sanand, Gujarat |
| Tata TSAT | Jagiroad, Assam |
| HCL-Foxconn India Chip | Jewar, Uttar Pradesh (NOT MP) |
| SicSem | Bhubaneswar, Odisha |
Which of the following statements with regard to Large Language Models (LLMs) used in machine learning is/are correct ?
- LLMs assign probabilities to the next possible words and then pick the one with the highest probability.
- LLMs process data through mathematical optimization to minimise prediction errors.
- LLMs produce unbiased outputs.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 — Correct. LLMs analyze input context and calculate a statistical probability distribution for the next possible word (token). In their basic form (greedy decoding), they pick the word with the highest probability. While real-world applications use controlled randomness (top-k sampling, temperature scaling) for creativity, the foundational mechanism is probability-based selection.
Statement 2 — Correct. LLM training relies on mathematical optimization:
- Algorithms like Stochastic Gradient Descent (SGD) and backpropagation iteratively adjust billions of model parameters
- The explicit goal is to minimize a "loss function" — a mathematical measure of prediction errors vs. actual training data
Statement 3 — Incorrect. LLMs do NOT produce unbiased outputs. Since they learn from massive human-generated datasets (internet text), they inherit, reflect, and sometimes amplify historical and societal biases — including gender, racial, and cultural stereotypes — present in training data.
Key Trick: Statement 3 uses an absolute term — "unbiased" — which is a classic UPSC red flag. No AI model trained on human data can be completely unbiased.
Which of the following statements with regard to India's indigenous new high resolution weather model, the 'Bharat Forecast System,' is/are correct?
- Its objective is to generate forecasts at the Panchayats cluster level.
- It was developed by IIT Delhi.
Select the answer using the code given below:
Detailed Explanation:
Statement 1 — Correct. A primary objective of the Bharat Forecast System (BFS) is to generate hyper-local weather forecasts down to the Panchayat cluster level (village and block level) to aid:
- Rural communities
- Agriculture planning
- Disaster management
It operates on an ultra-fine 6 km × 6 km grid (upgraded from India's previous 12 km resolution models) — making it the highest-resolution operational global weather model used by any national meteorological agency in the world.
Statement 2 — Incorrect. BFS was indigenously developed by the Indian Institute of Tropical Meteorology (IITM), Pune — an autonomous institute under the Ministry of Earth Sciences (MoES) — NOT IIT Delhi.
It is powered by:
| Supercomputer | Location |
|---|---|
| Arka | IITM, Pune |
| Arunika | NCMRWF, Noida |
Key Trick: "IIT Delhi" vs "IITM Pune" — a deliberate acronym confusion trap. IITM = Indian Institute of Tropical Meteorology, not IIT.
Which of the following statements with regard to Black Boxes used in modern aircrafts is/are correct ?
- They carry a beacon emitting red light pulses to facilitate underwater detection.
- They record both the cockpit voice and flight data.
- Their memory units are made using either stainless steel or titanium.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 is incorrect because black boxes use an Underwater Locator Beacon (ULB) that emits acoustic/ultrasonic signals, not red light pulses, for underwater detection.
Statements 2 and 3 are correct. Black boxes record both cockpit voice and flight data, and their crash-survivable memory units are protected by stainless steel or titanium.
Therefore, Option B (2 and 3 only) is correct.
A "black box" is the collective term for the Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR). These devices help investigators determine the cause of an aircraft accident. They are designed to survive extreme impact, fire, and deep-sea pressure.
Which of the following statements regarding the features of blockchain technology are correct?
- Records stored in the database may be made visible to relevant stakeholders without risk of alteration.
- Copies of the entire database are stored on multiple computers on a network, syncing within seconds.
- Consortium blockchain is a blend of public and private blockchains allowing selective data access.
- Mathematical algorithms make it impossible to change or delete any data once recorded and accepted.
Select the answer using the code given below:
Detailed Explanation:
All four statements correctly describe blockchain technology. Blockchain stores identical copies of data across multiple nodes, allows transparent record-sharing, supports consortium (hybrid) blockchains, and uses cryptographic algorithms to make tampering extremely difficult.
However, since there is no option containing 1, 2, 3, and 4, the best available answer is Option C (1, 2 and 4).
Blockchain is a distributed digital ledger where transactions are stored in linked blocks secured by cryptography. Its key features are decentralization, transparency, immutability, and security, making it useful in finance, supply chains, and digital governance.
Which of the following statements with regard to India's Deep Ocean Mission is/are correct?
- It was launched by the Ministry of Ports, Shipping and Waterways, Government of India.
- Matsya-6000 has been designed to carry 3 people for deep sea exploration.
- Samudrayaan is a project under this mission.
Select the answer using the code given below:
Detailed Explanation:
Statement 1 is incorrect because the Deep Ocean Mission (DOM) is implemented by the Ministry of Earth Sciences (MoES), not the Ministry of Ports, Shipping and Waterways.
Statements 2 and 3 are correct. Matsya-6000 is designed to carry 3 people up to a depth of 6,000 meters, and Samudrayaan is India's manned deep-sea exploration project under the Deep Ocean Mission.
Therefore, Option B (2 and 3 only) is correct.
The Deep Ocean Mission is a flagship initiative aimed at exploring and utilizing ocean resources. Its major goals include deep-sea mining, marine biodiversity studies, underwater technology development, and climate research. Samudrayaan and Matsya-6000 are key components of this mission.
Which of the following statements with regard to the National Quantum Mission (NQM) is/are correct?
- It aims at developing intermediate-scale quantum computers with 50-1000 physical qubits.
- Its implementation includes setting up of four Thematic Hubs (T-Hubs) in academic and national R&D institutes across India.
Select the answer using the code given below:
Detailed Explanation:
Both statements are correct. The National Quantum Mission (NQM) aims to develop intermediate-scale quantum computers with 50–1000 physical qubits over an 8-year period.
The mission also establishes four Thematic Hubs (T-Hubs) in leading academic and R&D institutions to advance quantum computing, communication, sensing, and materials research.
Therefore, Option C (Both 1 and 2) is correct.
The National Quantum Mission (2023–2031) aims to make India a global leader in quantum technologies. It focuses on quantum computing, secure quantum communication, quantum sensors, and advanced quantum materials, which can revolutionize fields like cybersecurity, healthcare, finance, and defense.
Which of the following statements with regard to GenomeIndia Project is/are correct ?
- It is a part of the Human Genome Project.
- The project is funded by the Department of Biotechnology (DBT), Government of India.
- Its primary aim is to build a catalogue of genetic diversity of the Indian population.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 is incorrect because the GenomeIndia Project is an independent Indian initiative and not a part of the Human Genome Project.
Statements 2 and 3 are correct. The project is funded by the Department of Biotechnology (DBT) and aims to create a comprehensive catalogue of the genetic diversity of the Indian population.
Therefore, Option B (2 and 3 only) is correct.
The GenomeIndia Project was launched in 2020 to sequence genomes from diverse Indian communities. It helps researchers understand genetic variations, improve disease diagnosis, develop personalized medicine, and strengthen biomedical research in India.
Which of the following statements with regard to drone swarms is/are correct ?
- They use Terahertz band of frequency to communicate with the command centre.
- Individual drones in the swarm can communicate with other drones in the swarm.
- GPS Spoofing is a commonly used technique to counter drone swarm attack.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 is incorrect because drone swarms generally use conventional radio frequency (RF) bands for communication with command centres, not the Terahertz (THz) band.
Statements 2 and 3 are correct. Drones within a swarm communicate with each other to coordinate actions, and GPS spoofing is a widely used countermeasure to mislead and disrupt drone swarm navigation.
Therefore, Option B (2 and 3 only) is correct.
A drone swarm is a group of drones that work together using autonomous coordination and inter-drone communication. Swarm technology is used in surveillance, military operations, disaster management, and mapping. Countermeasures include jamming, GPS spoofing, and directed-energy systems.
Which of the following items of defence hardware is/are manufactured in India ?
- Su-30 MKI Fighter Jets
- T-90 MK-III Tanks
- Akula Class Submarine
Select the answer using the code given below :
Detailed Explanation:
Statements 1 and 2 are correct. Su-30 MKI fighter jets are manufactured in India by HAL under a technology-transfer agreement, while T-90 Mk-III (Bhishma) tanks are produced in India at the Heavy Vehicles Factory, Avadi.
Statement 3 is incorrect because Akula-class submarines are designed and built in Russia. India has only leased these submarines and does not manufacture them.
Therefore, Option A (1 and 2) is correct.
India follows a policy of defence indigenisation, promoting domestic production of military equipment through technology transfer, licensed manufacturing, and indigenous development. This supports self-reliance under the Atmanirbhar Bharat initiative in the defence sector.
Consider the following statements about Mission Sudarshan Chakra of India:
- It aims to enhance India's air defence, ballistic missile defence and aerial offensive capabilities.
- This Mission is being designed to enhance rapid, precise, and powerful defence responses, reinforcing India's strategic autonomy.
- One of the aims of this Mission is to cover all public places of India by an expanded nationwide security shield by 2035.
Which of the statements given above is/are correct?
Detailed Explanation:
All three statements are correct. Mission Sudarshan Chakra is a proposed integrated security initiative aimed at strengthening India's air defence, ballistic missile defence, and offensive capabilities.
It incorporates advanced technologies to enable rapid and precise responses while promoting strategic autonomy. The mission also envisions extending a nationwide security shield to public places across India by 2035.
Therefore, Option A (1, 2 and 3) is correct.
Mission Sudarshan Chakra is a long-term defence modernization initiative focused on creating a layered security architecture using indigenous technologies. It integrates air defence systems, missile defence, AI-enabled surveillance, space-based monitoring, and advanced weapons to enhance national security.
Consider the following statements with respect to the AI Impact Summit, 2026 held in New Delhi :
- The Summit's intellectual framework was based on three foundational Sutras : People, Planning, and Progress.
- The Preamble of the Summit stresses Democratising AI Resources, which acknowledges the Charter for Democratic Diffusion of AI as a binding framework to support locally relevant innovation and strengthen resilient AI ecosystems while respecting national laws.
- The New Delhi Declaration on AI Impact was structured around seven Chakras (Pillars), which included Access for Social Empowerment, AI for Science, and Secure and Trusted AI.
Which of the statements given above is/are correct ?
Detailed Explanation:
Statements 1 and 2 are incorrect. The AI Impact Summit 2026 was based on the three Sutras of People, Planet, and Progress, not People, Planning, and Progress. Also, the Charter for Democratic Diffusion of AI was introduced as a voluntary, non-binding framework, not a binding one.
Statement 3 is correct. The New Delhi Declaration on AI Impact was organized around seven Chakras (Pillars), including Access for Social Empowerment, AI for Science, and Secure and Trusted AI.
Therefore, Option D (3 only) is correct.
The AI Impact Summit 2026 focused on promoting inclusive, responsible, and human-centric AI development. The New Delhi Declaration emphasized equitable access to AI resources, innovation, trust, safety, and global cooperation while respecting national priorities.
Which of the following statements with regard to Green Hydrogen is/are correct ?
- It is decarbonized hydrogen obtained from natural gas reforming combined with carbon capture and storage (CCS).
- It is produced using electrolysis of water with electricity generated by renewable energy.
- National Green Hydrogen Mission of India aims for abatement of nearly 50 MMT of annual greenhouse gas emissions by 2030.
Select the answer using the code given below :
Detailed Explanation:
Statement 1 — Incorrect. This describes Blue Hydrogen, NOT Green Hydrogen. Blue Hydrogen comes from natural gas + carbon capture (CCS). Green Hydrogen uses a completely different method (see Statement 2).
Statement 2 — Correct. Green Hydrogen = splitting water (electrolysis) using electricity from renewable sources (solar/wind). It's a zero-emission process.
Statement 3 — Correct. India's National Green Hydrogen Mission targets:
- 5 MMT/year production capacity by 2030
- This leads to ~50 MMT reduction in greenhouse gas emissions annually
- Plus reduces fossil fuel imports and creates 6 lakh+ jobs
Memory Trick: Color-code hydrogen by source:
- Green = Renewable electricity + water (clean)
- Blue = Natural gas + carbon capture (cleaner fossil)
- Grey = Natural gas, no carbon capture (dirty)
UPSC Prelims 2026 - Science & Technology Chapter-wise Distribution
Science & Technology Current Affairs
6 Qs (31.6%)Defence Technology
5 Qs (26.3%)Physics and Applied Technology
2 Qs (10.5%)Biotechnology
2 Qs (10.5%)Artificial Intelligence & Emerging Technologies
1 Qs (5.3%)Space Technology
1 Qs (5.3%)Energy Technology
1 Qs (5.3%)Information & Communication Technology
1 Qs (5.3%)UPSC Prelims 2026 - Science & Technology Questions FAQs
Q1 How many Science & Technology questions were asked in UPSC Prelims 2026?
Q2 What is the chapter-wise question distribution for Science & Technology in UPSC Prelims 2026?
- Science & Technology Current Affairs: 6 questions (31.6%)
- Defence Technology: 5 questions (26.3%)
- Physics and Applied Technology: 2 questions (10.5%)
- Biotechnology: 2 questions (10.5%)
- Artificial Intelligence & Emerging Technologies: 1 questions (5.3%)
- Space Technology: 1 questions (5.3%)
- Energy Technology: 1 questions (5.3%)
- Information & Communication Technology: 1 questions (5.3%)