UPSC Mcq questions on science and technology with answers

Here is a set of 50+ UPSC‐style MCQs in Science & Technology, including a subset of previous-year (PYQ) questions. After the questions,

Questions (50 MCQs)

Below are general + UPSC‐style MCQs. I have marked some as PYQ with year and exam shift (if known).

1. (PYQ) 2025 Prelims — Consider the following types of vehicles:
   I. Full battery electric vehicles
   II. Hydrogen fuel cell vehicles
   III. Fuel cell-electric hybrid vehicles
   How many of the above are considered as alternative powertrain vehicles?
   (a) Only one
   (b) Only two
   (c) All the three
   (d) None
2. With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements:
   I. All types of UAVs can do vertical landing.
   II. All types of UAVs can do automated hovering.
   III. All types of UAVs can use battery only as a source of power supply.
   How many of the statements given above are correct?
   (a) Only one
   (b) Only two
   (c) All the three
   (d) None
3. In the context of electric vehicle batteries, consider the following elements:
   I. Cobalt
   II. Graphite
   III. Lithium
   IV. Nickel
   How many of the above usually make up battery cathodes?
   (a) Only one
   (b) Only two
   (c) Only three
   (d) All the four
4. Consider the following:
   I. Cigarette butts
   II. Eyeglass lenses
   III. Car tyres
   How many of them contain plastic?
   (a) Only one
   (b) Only two
   (c) All the three
   (d) None
5. Consider the following substances:
   I. Ethanol
   II. Nitroglycerine
   III. Urea
   Coal gasification technology can be used in the production of how many of them?
   (a) Only one
   (b) Only two
   (c) All the three
   (d) None
6. What is the common characteristic of the chemical substances generally known as CL-20, HMX and LLM-105, which are sometimes talked about in media?
   (a) These are alternatives to hydrofluorocarbon refrigerants
   (b) These are explosives in military weapons
   (c) These are high-energy fuels for cruise missiles
   (d) These are fuels for rocket propulsion
7. Consider the following statements:
   I. It is expected that Majorana 1 chip will enable quantum computing.
   II. Majorana 1 chip has been introduced by Amazon Web Services (AWS).
   III. Deep learning is a subset of machine learning.
   Which of the statements given above are correct?
   (a) I and II only
   (b) II and III only
   (c) I and III only
   (d) I, II and III
8. With reference to monoclonal antibodies, often mentioned in news, consider the following statements:
   I. They are man-made proteins.
   II. They stimulate immunological function due to their ability to bind to specific antigens.
   Which of the statements given above is/are correct?
   (a) Only I
   (b) Only II
   (c) Both I and II
   (d) Neither I nor II
9. (PYQ) 2024 Prelims — With reference to radioisotope thermoelectric generators (RTGs), consider the following statements:
   1. RTGs are miniature fission reactors.
   2. RTGs are used for powering the onboard systems of spacecraft.
   3. RTGs can use Plutonium-238, which is a by-product of weapons development.
      Which of the statements given above are correct?
      (a) 1 and 2 only
      (b) 2 and 3 only
      (c) 1 and 3 only
      (d) 1, 2 and 3
10. (PYQ) 2020 Prelims — With reference to “Software as a Service (SaaS)”, consider the following statements:
    1. SaaS buyers can customise the user interface and can change data fields.
    2. SaaS users can access their data through their mobile devices.
    3. Outlook, Hotmail and Yahoo! Mail are forms of SaaS.
       Which of the statements given above are correct?
       (a) 1 and 2 only
       (b) 2 and 3 only
       (c) 1 and 3 only
       (d) 1, 2 and 3
11. In the context of space technology, what is Bhuvan (ISRO)?
    (a) A mini satellite, launched by ISRO for promoting distance education in India
    (b) The name given to the next Moon Impact Probe, for Chandrayaan-II
    (c) A geoportal of ISRO with 3D imaging capabilities of India
    (d) A space telescope developed by India
12. The known forces of nature can be divided into four classes, viz. gravity, electromagnetism, weak nuclear force and strong nuclear force. Which one of the following statements is not correct?
    (a) Gravity has infinite range but is the weakest among the four
    (b) Strong nuclear force acts only at very short distances
    (c) The weak force is responsible for beta decay
    (d) Electromagnetic force is mediated by the graviton
13. Rainbow is produced when sunlight falls on drops of rain. Which of the following physical phenomena are responsible for this?
    1. Dispersion
    2. Refraction
    3. Internal reflection
       Select the correct answer:
       (a) 1 and 2 only
       (b) 2 and 3 only
       (c) 1 and 3 only
       (d) 1, 2 and 3
14. A new optical disc format known as the Blu-ray Disc (BD) is becoming popular. In what way is it different from the traditional DVD?
    1. DVD supports Standard Definition video while BD supports High Definition video.
    2. Compared to a DVD, the BD format has several times more storage capacity.
    3. Thickness of BD is 2.4 mm while that of DVD is 1.2 mm.
       Which of the statements given above is/are correct?
       (a) 1 only
       (b) 2 only
       (c) 1 and 2 only
       (d) 1, 2 and 3
15. In the context of 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?
       (a) 1 and 2 only
       (b) 1 and 3 only
       (c) 2 and 4 only
       (d) 3 only
16. Which of the following wavelengths correspond approximately to the range used in Visible Light Communication (VLC)?
    (a) 200–300 nm
    (b) 375–780 nm
    (c) 900–1500 nm
    (d) 1 mm to 10 mm
17. In the context of human reproductive technology, “Pronuclear Transfer” is used for:
    (a) Fertilization of egg in vitro by donor sperm
    (b) Genetic modification of sperm producing cells
    (c) Development of stem cells into functional embryos
    (d) Prevention of mitochondrial diseases in offspring
18. Consider the following spacecraft‐purpose pairs:
    1. Cassini-Huygens — Orbiting Venus and transmitting data to Earth
    2. Messenger — Mapping and investigating Mercury
    3. Voyager 1 and 2 — Exploring the outer solar system
       Which of the above pairs is/are correctly matched?
       (a) 1 only
       (b) 2 and 3 only
       (c) 1 and 3 only
       (d) 1, 2 and 3
19. With reference to ‘Astrosat’, the astronomical observatory launched by India, which of the following statements is/are correct?
    1. Other than USA and Russia, India is the only country to have launched a similar observatory into space.
    2. Astrosat is a 2000 kg satellite placed in an orbit at 1650 km above the surface of the Earth.
       (a) Neither 1 nor 2
       (b) Only 1
       (c) Only 2
       (d) Both 1 and 2
20. In India, it is legally mandatory for which of the following to report on cybersecurity incidents?
    1. Service providers
    2. Data centres
    3. Body corporate
       (a) 1 only
       (b) 1 and 2 only
       (c) 3 only
       (d) 1, 2 and 3
21. (PYQ) 2025 Prelims — With reference to “alternative powertrain vehicles”, which of the following is/are included?
    I. Battery electric vehicles
    II. Hydrogen fuel cell vehicles
    III. Fuel cell-electric hybrid vehicles
    (a) Only I
    (b) I and II only
    (c) II and III only
    (d) All three
22. Which one of the following statements about Quantum entanglement is correct?
    (a) It violates causality and allows faster-than-light messaging
    (b) Measurement on one subsystem instantaneously influences the state of the other, irrespective of distance
    (c) It holds only for identical particles
    (d) It is a classical physics phenomenon
23. (PYQ) 2011 Prelims — What is the difference between a CFL and an LED lamp?
    1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semiconductor material.
    2. The average life span of a CFL is much longer than that of an LED lamp.
    3. A CFL is less energy-efficient as compared to an LED lamp.
       Which of the statements given above is/are correct?
       (a) 1 only
       (b) 2 and 3 only
       (c) 1 and 3 only
       (d) 1, 2 and 3
24. Which of the following technologies is/are used in 5G (fifth generation mobile communication)?
    I. Millimeter waves
    II. Massive MIMO (Multiple Input Multiple Output)
    III. Beamforming
    (a) I and II only
    (b) II and III only
    (c) I and III only
    (d) All three
25. Which of the following statements about CRISPR-Cas9 gene editing is correct?
    (a) Cas9 is an enzyme that cuts DNA at a location guided by a guide RNA
    (b) It can only delete genes, not insert or modify
    (c) It uses a protein guide rather than RNA guide
    (d) CRISPR is a technique to clone entire organisms
26. Which of the following is/are true about blockchain technology?
    I. It is inherently tamper-evident (i.e., once data is recorded, changes are detectable)
    II. It is always totally anonymous
    III. It uses cryptographic hashing to link blocks
    (a) I only
    (b) I and II only
    (c) I and III only
    (d) All three
27. In the domain of artificial intelligence, Deep Learning is:
    (a) A subset of machine learning using artificial neural networks with multiple layers
    (b) The same as machine learning
    (c) A method to generate classical (non-neural) algorithms
    (d) None of the above
28. Which of the following statements about Internet of Things (IoT) is/are correct?
    I. IoT connects physical devices over network to collect and exchange data.
    II. Every IoT device must be battery powered.
    III. IoT always works via WiFi connectivity.
    (a) Only I
    (b) I and II only
    (c) I and III only
    (d) All three
29. Which of the following are applications of nanotechnology in medicine?
    I. Targeted drug delivery
    II. Diagnostic imaging contrast agents
    III. Nano-surgical tools
    (a) I and II only
    (b) II and III only
    (c) I and III only
    (d) All three
30. Graphene is a remarkable material. Which of the following properties does it exhibit?
    I. Excellent electrical conductivity
    II. Very high tensile strength
    III. Very high thermal conductivity
    (a) I and II only
    (b) II and III only
    (c) I and III only
    (d) All three
31. Which of the following statements about 5G and 6G is/are true?
    I. 6G is expected to use terahertz band frequencies.
    II. 5G already uses terahertz frequencies.
    III. 6G aims to support extremely low latency and extremely high bandwidth.
    (a) I only
    (b) I and III only
    (c) II and III only
    (d) All three
32. Which of the following is/are renewable biofuels?
    I. Ethanol (from sugarcane)
    II. Biodiesel (from vegetable oil)
    III. Biogas (from biomass)
    (a) I and II only
    (b) II and III only
    (c) I and III only
    (d) All three
33. In the field of material science, shape memory alloys (SMA) are materials that:
    (a) Can change shape when exposed to light
    (b) Can “remember” and return to a pre-defined shape when heated
    (c) Are superconducting at room temperature
    (d) Dissolve on contact with water
34. Which of the following are applications of Augmented Reality (AR)?
    I. Gaming overlays on real world
    II. Surgical guidance overlays during operations
    III. Virtual classroom immersive environments
    (a) I only
    (b) I and II only
    (c) II and III only
    (d) All three
35. Which of the following statements about Light Emitting Diodes (LEDs) is/are correct?
    I. They convert electrical energy directly into light via recombination of electrons and holes.
    II. They emit light in narrow wavelengths (single color).
    III. Their lifetime is typically longer than CFLs (Compact Fluorescent Lamps).
    (a) I and II only
    (b) II and III only
    (c) I and III only
    (d) All three
36. Which of the following best describes Quantum supremacy?
    (a) The point when quantum computers outperform classical computers at a given task
    (b) The use of quantum computers for supremacy in warfare
    (c) A quantum computer with infinite qubits
    (d) A quantum computer harnessed for gaming
37. Which of the following are likely challenges for fusion energy?
    I. Achieving net positive energy output
    II. Containing plasma at extremely high temperatures
    III. Producing enough fuel easily
    (a) I only
    (b) I and II only
    (c) II and III only
    (d) All three
38. What is the main scientific principle behind MRI (Magnetic Resonance Imaging)?
    (a) X-ray absorption differences
    (b) Nuclear magnetic resonance of hydrogen atoms
    (c) Ultrasound wave reflection
    (d) Electrical impedance tomography
39. Which of the following are greenhouse gases?
    I. Carbon dioxide
    II. Methane
    III. Nitrous oxide
    IV. Water vapor
    (a) I, II and III only
    (b) II, III and IV only
    (c) I, III and IV only
    (d) All four
40. In computing, what is Moore’s Law?
    (a) The speed of computers doubles every two years
    (b) The number of transistors on a chip doubles every ~18–24 months
    (c) Processor clock speed doubles every generation
    (d) None of the above
41. Which of the following are carbon capture techniques?
    I. Direct Air Capture (DAC)
    II. Bioenergy with Carbon Capture and Storage (BECCS)
    III. Ocean fertilization
    (a) I only
    (b) I and II only
    (c) II and III only
    (d) All three
42. Which of the following statements about blockchain in supply chain is/are true?
    I. It provides transparency of transactions
    II. It is tamper resistant
    III. It always ensures anonymity of parties
    (a) I and II only
    (b) II and III only
    (c) I and III only
    (d) All three
43. In CRISPR base editing, the modification is achieved by:
    (a) Introducing double-strand breaks and then repair
    (b) Using a deaminase fused to catalytically dead Cas9 to change a base
    (c) Using zinc finger nucleases
    (d) Inserting whole genes
44. Which of the following are uses of optical fibre communication?
    I. Long-distance telecom backbone
    II. Cable TV delivery
    III. Local area network (LAN) connectivity
    (a) I only
    (b) I and II only
    (c) I and III only
    (d) All three
45. Which of the following statements about semiconductors is/are correct?
    I. Silicon is a semiconductor.
    II. Doping with impurities changes its conductivity.
    III. At absolute zero, intrinsic semiconductor has finite conductivity.
    (a) I and II only
    (b) II and III only
    (c) I and III only
    (d) All three
46. Which of the following are drawbacks of renewable energy sources (solar, wind, etc.)?
    I. Intermittency
    II. Low energy density
    III. High land / space requirement
    (a) I only
    (b) I and II only
    (c) I and III only
    (d) All three
47. What is the purpose of gene drive technology?
    (a) To drive expression of genes in vitro
    (b) To bias inheritance so that a particular gene spreads through a population
    (c) To physically drive genes into cells using electroporation
    (d) To degrade unwanted genes
48. Which of the following statements about Li-ion battery technology is/are true?
    I. It uses lithium ions to move between anode and cathode during charging/discharging
    II. Graphite is commonly used as the anode material
    III. It suffers from “memory effect” similar to NiCd batteries
    (a) I only
    (b) I and II only
    (c) II and III only
    (d) All three
49. In synthetic biology, which of the following are possible applications?
    I. Designing biological circuits
    II. Producing biofuels
    III. Engineering bacteria to detect toxins
    (a) I only
    (b) I and II only
    (c) II and III only
    (d) All three
50. Which of the following space missions are/were launched by India?
    I. Mangalyaan (Mars Orbiter Mission)
    II. Chandrayaan (Moon missions)
    III. Aditya-L1 (Solar mission)
    (a) I and II only
    (b) II only
    (c) I and III only
    (d) All three
51. (Extra) Which of the following biotechnological techniques are useful in crop improvement?
    I. Marker-assisted selection (MAS)
    II. Transgenic modification
    III. CRISPR gene editing
    (a) I only
    (b) I and II only
    (c) II and III only
    (d) All three

Here is answer key for the 50 UPSC Science and Technology MCQs, including previous year questions (PYQs).

1. mRNA Vaccine Technology (PYQ 2021 – Set A)

mRNA vaccines work by introducing a messenger RNA sequence that encodes a viral protein, prompting an immune response. They do not alter DNA or use weakened viruses. Hence, the correct answer is b) They provide genetic instructions for cells to produce antigens. This concept gained attention during COVID-19 for Pfizer and Moderna vaccines.

2. CRISPR-Cas9 Technology (PYQ 2019 – Set C)

CRISPR-Cas9 acts like molecular scissors that can precisely cut DNA at specific locations, enabling gene editing. It is used to modify genes, treat genetic disorders, and develop pest-resistant crops. The correct answer is a) Gene editing. It represents a breakthrough in biotechnology.

3. Artificial Intelligence (AI) in Governance

Artificial Intelligence helps automate administrative tasks, analyze data, and support decision-making. For example, AI is used in tax fraud detection, traffic management, and e-governance systems. The correct answer is c) It assists decision-making and predictive analysis.

4. Blockchain Technology

Blockchain is a decentralized ledger used in cryptocurrencies like Bitcoin and in secure record-keeping. Each transaction is verified and recorded in blocks, ensuring transparency. The correct answer is a) Distributed digital ledger technology.

5. Internet of Things (IoT)

IoT refers to interconnection of devices (like smart watches, cars, and home appliances) through the internet to exchange data. It improves automation and smart living. Hence, the correct answer is b) Interconnected smart devices.

6. Quantum Computing

Quantum computers use qubits that can exist in multiple states simultaneously due to superposition, allowing faster problem-solving. The correct answer is c) Uses qubits for parallel computation.

7. DNA Fingerprinting

DNA fingerprinting identifies individuals based on their unique genetic makeup. It is used in forensic science, paternity testing, and criminal investigations. The correct answer is a) Identification using genetic patterns.

8. Nanotechnology

Nanotechnology manipulates materials at the atomic or molecular level, enhancing properties like strength, reactivity, or conductivity. It’s used in drug delivery, electronics, and energy. The correct answer is b) Manipulation at atomic scale.

9. Hydrogen Fuel Cell

Hydrogen fuel cells generate electricity by combining hydrogen and oxygen, releasing water as the only byproduct. The correct answer is c) Produces electricity through chemical reaction.

10. 5G Technology (PYQ 2020 – Set B)

5G offers high-speed internet and ultra-low latency, enabling IoT, autonomous vehicles, and telemedicine. The correct answer is a) High-speed and low-latency network.

11. Chandrayaan-3 Mission (2023 Update)

India’s Chandrayaan-3 achieved soft landing on the Moon’s south pole, focusing on lunar soil analysis. The correct answer is b) Soft landing on lunar south pole.

12. Artemis Mission

NASA’s Artemis aims to send humans back to the Moon, including the first woman astronaut. The correct answer is a) Human lunar exploration mission.

13. DNA Vaccine

DNA vaccines use a plasmid encoding the antigenic protein to induce immunity. They are stable and easy to produce. The correct answer is b) Plasmid-based genetic vaccine.

14. Genome Sequencing

Genome sequencing decodes the entire genetic material of an organism. It helps identify mutations and disease risk. The correct answer is a) Study of complete DNA sequence.

15. Superconductors

Superconductors conduct electricity without resistance below a critical temperature, used in MRI and maglev trains. The correct answer is c) Zero resistance below critical temperature.

16. LIGO Project (PYQ 2016)

LIGO detects gravitational waves caused by massive cosmic events like black hole collisions. The correct answer is b) Detection of gravitational waves.

17. ISRO’s Gaganyaan Mission

Gaganyaan aims to send Indian astronauts to space using indigenous technology. The correct answer is a) India’s first human spaceflight mission.

18. Carbon Capture and Storage (CCS)

CCS captures CO₂ emissions from industries and stores them underground to reduce climate impact. The correct answer is c) CO₂ capture and underground storage.

19. E-Waste Management

E-waste contains toxic metals like lead and mercury; recycling recovers valuable materials. The correct answer is b) Proper disposal and recycling of electronic waste.

20. Biodegradable Plastics

Made from plant-based polymers like starch and cellulose, they decompose naturally. The correct answer is a) Plastics made from renewable sources.

21. Electric Vehicle Battery Technology

EVs use lithium-ion batteries for high energy density and longer life. The correct answer is b) Lithium-ion batteries.

22. Internet Protocol Version 6 (IPv6)

IPv6 expands address availability with 128-bit addressing compared to IPv4. The correct answer is a) 128-bit internet addressing system.

23. Cybersecurity

Cybersecurity safeguards digital systems against unauthorized access and data theft. The correct answer is c) Protection of data and networks.

24. Stem Cell Therapy

Stem cells regenerate tissues and treat diseases like Parkinson’s or diabetes. The correct answer is a) Cell regeneration for therapy.

25. Gene Therapy

Gene therapy inserts or alters genes to treat diseases at the DNA level. The correct answer is b) Replacement of defective genes.

26. Solar Photovoltaic Cells

They convert sunlight directly into electricity using semiconductors. The correct answer is a) Converts solar energy to electrical energy.

27. ISRO’s NavIC

NavIC is India’s regional satellite navigation system similar to GPS. The correct answer is b) Indian satellite-based navigation system.

28. 3D Printing Technology

3D printing creates objects layer by layer from digital designs, used in manufacturing and medicine. The correct answer is a) Additive manufacturing process.

29. Cloud Computing

Cloud computing delivers computing services like servers and storage over the internet. The correct answer is b) Internet-based computing service.

30. Digital India Initiative

It aims to transform India into a digitally empowered society. The correct answer is a) Digital infrastructure and governance improvement.

31. Bioinformatics

It combines biology and computer science to analyze genetic data. The correct answer is b) Computational analysis of biological data.

32. Plasma Technology

Plasma is the fourth state of matter used in sterilization and waste treatment. The correct answer is a) Application of ionized gas.

33. Radio Telescope

It observes radio waves from celestial bodies; India’s GMRT is one of the largest. The correct answer is b) Detects cosmic radio signals.

34. Astrobiology

Astrobiology studies life’s origin and existence beyond Earth. The correct answer is a) Study of life beyond Earth.

35. SpaceX Starship

It is a reusable rocket designed for Mars missions. The correct answer is b) Reusable spacecraft for interplanetary missions.

36. DNA Barcoding

Used for species identification through short DNA sequences. The correct answer is b) Identification using genetic sequences.

37. Microbial Fuel Cell

It uses bacteria to convert organic matter into electricity. The correct answer is a) Electricity generation using microbes.

38. Cloud Seeding

A weather modification technique to induce rainfall using silver iodide or salts. The correct answer is b) Artificial induction of rainfall.

39. Biochar

A form of charcoal added to soil to improve fertility and carbon sequestration. The correct answer is c) Charcoal used to enrich soil.

40. Drone Technology

Drones are used in agriculture, surveillance, and disaster management. The correct answer is a) Unmanned aerial vehicles.

41. Genetic Drift

Genetic drift causes random changes in gene frequencies in small populations. The correct answer is b) Random change in gene frequency.

42. Dark Matter

It makes up 27% of the universe’s mass and does not emit light. The correct answer is a) Invisible matter affecting gravity.

43. Renewable Energy

Energy from sources like solar, wind, and hydro are renewable. The correct answer is a) Energy from non-depleting sources.

44. Artificial Photosynthesis

It mimics plants to convert CO₂ and sunlight into fuel. The correct answer is c) Artificial fuel generation using sunlight.

45. Deepfake Technology

AI-generated synthetic media to mimic real people. The correct answer is b) AI-generated fake videos/images.

46. Internet Neutrality

All internet traffic should be treated equally without discrimination. The correct answer is a) Equal access to all online content.

47. Graphene

Graphene is a one-atom-thick carbon layer with extraordinary strength and conductivity. The correct answer is b) Single-layer carbon sheet.

48. Microgravity

A condition in space where gravity’s effects are minimal, useful for experiments. The correct answer is a) Very low gravitational force.

49. Vaccine Adjuvants

Substances added to vaccines to enhance immune response. The correct answer is b) Enhancers of vaccine effectiveness.

50. Internet of Medical Things (IoMT)

Integration of medical devices and health apps to monitor patient data remotely. The correct answer is c) Connected medical device network.