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UPPSC 2025 — Science & Technology Questions with Answers

All 35 Science & Technology previous-year questions from UPPSC 2025, each with the correct answer and a full explanation. Practise them as a free, timed mock test with instant scoring.

1. Q1.Science

   Consider the following elements found in a typical 70 kg man and arrange them in correct increasing order. 1. Sodium 2. Potassium 3. Copper 4. Iron Select the correct answer from the code given below:

   • a)4, 3, 1, 2
   • b)3, 4, 2, 1
   • c)3, 4, 1, 2
   • d)4, 3, 2, 1
2. Q2.Science

   With reference to 'acid and bases', which of the following statements is/are correct? 1. Acidic solutions have pH more than 7. 2. Basic solutions have pH less than 7. Select the correct answer from the code given below:

   • a)(a) Only 2
   • b)(b) Neither 1 nor 2
   • c)(c) Both 1 and 2
   • d)(d) Only 1
3. Q3.Science

   With reference to 'Isotopes', which of the following statements is/are correct? 1. Atoms with identical atomic numbers but different atomic mass numbers are known as isotopes. 2. Protium, Deuterium and Tritium are isotopes of carbon. Select the correct answer from the code given below:

   • a)(a) Only 2
   • b)(b) Neither 1 nor 2
   • c)(c) Both 1 and 2
   • d)(d) Only 1
4. Q4.Science

   Arrange the following electromagnetic radiations in decreasing order of their frequencies. 1. Gamma rays 2. Ultraviolet rays 3. Radio waves 4. X-rays Choose the correct answer from the codes given below:

   • a)(a) 1, 4, 3, 2
   • b)(b) 4, 1, 2, 3
   • c)(c) 1, 4, 2, 3
   • d)(d) 4, 1, 3, 2
5. Q5.Science

   Given below are two statements, one is labelled as Assertion (A) and the other as Reason (R). Assertion (A): Evaporation of sweat from human skin dissipates body heat. Reason (R): High humidity on a hot day increases discomfort. Select the correct answer from the code given below:

   • a)Code: (a) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
   • b)Code: (b) (A) is false, but (R) is true
   • c)Code: (c) (A) is true, but (R) is false
   • d)Code: (d) Both (A) and (R) are true and (R) is the correct explanation of (A)
6. Q6.Current Affairs / Science & Technology

   130. Iron dome missile defence system belongs to which of the following countries? 1. France 2. United States of America 3. Israel Select the correct answer from the code given below:

   • a)(a) 1 and 2
   • b)(b) Only 3
   • c)(c) 2 and 3
   • d)(d) Only 1
7. Q7.Science

   Two statements are given below, one is labelled as Assertion (A) and the other as Reason (R). Assertion (A): Voices of males and females are different. Reason (R): The length and thickness of vocal cords in males and females are different. Choose the correct answer from the code given below:

   • a)a) (A) and (R) both are correct, but (R) is not the correct explanation of (A).
   • b)b) (A) is false, but (R) is correct.
   • c)c) (A) is correct, but (R) is false.
   • d)d) (A) and (R) both are correct and (R) is the correct explanation of (A).
8. Q8.Science

   With reference to 'Silver articles', which of the following statements is/are correct? 1. Silver articles turn black after some time when exposed to air. 2. It happens due to coating of silver sulphide. Select the correct answer from the code given below: Code: (a) Only 2 (b) Neither 1 nor 2 (c) Both 1 and 2 (d) Only 1

   • a)(a) Only 2
   • b)(b) Neither 1 nor 2
   • c)(c) Both 1 and 2
   • d)(d) Only 1
9. Q9.Science & Technology

   Match List I with List II and select the correct answer using the code given below the lists: List-I (Mission) A. Chandrayaan-3 B. Aditya L1 C. INSAT-3DS D. RLV-LEX-01 List-II (Date of Launch) 1. 02 September 2023 2. 17 February 2024 3. 14 July 2023 4. 02 April 2023 Code: (a) 1 3 4 2 (b) 3 1 2 4 (c) 3 1 4 2 (d) 1 3 2 4

   • a)(a) 1 3 4 2
   • b)(b) 3 1 2 4
   • c)(c) 3 1 4 2
   • d)(d) 1 3 2 4
10. Q10.Science

    Which of the following two are the major constituent of Bio-gas ? 1. Methane 2. Butane 3. Carbon dioxide 4. Carbon monoxide Select the correct answer from the code given below:

    • a)(a) 1 and 3
    • b)(b) 3 and 4
    • c)(c) 2 and 3
    • d)(d) 1 and 2
11. Q11.Science

    Two statements are given below, one labelled as Assertion (A) and the other as Reason (R). Assertion (A): Generally, an alloy of lead and tin is used as the material for fuse wire. Reason (R): The melting point of an alloy of lead and tin is higher than that of copper and aluminium. Select the correct answer using the code given below:

    • a)(a) (A) and (R) both are true, but (R) is not the correct explanation of (A)
    • b)(b) (A) is false, but (R) is true
    • c)(c) (A) is true, but (R) is false
    • d)(d) (A) and (R) both are true and (R) is the correct explanation of (A)
12. Q12.Science

    Which of the following gasses is/are lighter than air? 1. Hydrogen chloride 2. Sulfur dioxide 3. Helium Select the correct answer from the code given below: Code:

    • a)(a) 1 and 2
    • b)(b) Only 3
    • c)(c) 2 and 3
    • d)(d) Only 1
13. Q13.Science

    With reference to 'ozone layer', which of the following statements is/are correct? 1. Ozone layer shields the surface of the earth from the ultra-violet radiations from the sun. 2. Ozone depletion has been linked to the chlorofluorocarbons. Select the correct answer from the code given below: Code:

    • a)(a) Only 2
    • b)(b) Neither 1 nor 2
    • c)(c) Both 1 and 2
    • d)(d) Only 1
14. Q14.Science

    Which of the following enzyme/enzymes is/are released in the stomach for protein digestion? 1. Chymotrypsin 2. Trypsin 3. Pepsin Choose the correct answer from the code given below:

    • a)(a) Only 1 and 2
    • b)(b) Only 3
    • c)(c) Only 2 and 3
    • d)(d) 1, 2 and 3
15. Q15.Science/Environment

    With reference to lichens, which of the following statements is/are correct? 1. Lichens are very good indicators of pollution. 2. Lichens grow well in polluted areas. Select the correct answer from the code given below: Code:

    • a)(a) Only 2
    • b)(b) Neither 1 nor 2.
    • c)(c) Both 1 and 2
    • d)(d) Only 1
16. Q16.Science

    In the context of 'Baking Soda', which of the following statements is/are correct? 1. It is sodium hydrogen carbonate. 2. It is used in fire extinguishers. Choose the correct answer from the code given below:

    • a)(a) Only 2
    • b)(b) Neither 1 nor 2
    • c)(c) Both 1 and 2
    • d)(d) Only 1
17. Q17.Science

    In the context of 'Earthworm', which of the following statement/s is/are correct? 1. Earthworms increase soil fertility and are known as 'farmers' friends'. 2. Earthworms have two pairs of hearts. Choose the correct answer from the code given below:

    • a)(a) Only 2
    • b)(b) Neither 1 nor 2
    • c)(c) Both 1 and 2
    • d)(d) Only 1
18. Q18.Science

    Which of the following pairs is/are NOT correctly matched? (Acid) (Acid found in) 1. Lactic acid - Curd 2. Tartaric acid - Grapes 3. Acetic acid - Potato Select the correct answer from the code given below: Code:

    • a)(a) 1 and 2
    • b)(b) Only 3
    • c)(c) 2 and 3
    • d)(d) Only 1
19. Q19.Science

    With reference to 'blood', which of the following statements is/are correct? 1. Blood is made up of plasma and various types of cells. 2. The presence of hemoglobin makes blood red. Choose the correct answer from the codes given below:

    • a)1 and 2
    • b)Only 3
    • c)2 and 3
    • d)Only 1
20. Q20.Science

    Which of the following statements is/are correct? 1. Dolphins and whales breathe through blowholes. 2. Earthworms breathe through their skin. Select the correct answer using the code given below:

    • a)Only 1
    • b)Only 2
    • c)1 and 2 both
    • d)Neither 1 nor 2
21. Q21.Space

    Consider the following statements: Statement I : Scientific studies suggest that a shift is taking place in the Earth's rotation and axis. Statement II : Solar flares and associated coronal mass ejections bombarded the Earth's outermost atmosphere with tremendous amount of energy. Statement III : As the Earth's polar ice melts, the water tends to move towards the equator. Which one of the following is correct in respect of the above statements?

    • a)Both Statement II and Statement III are correct and both of them explain Statement I
    • b)Both Statement II and Statement III are correct but only one of them explains Statement I
    • c)Only one of the Statements II and III is correct and that explains Statement I
    • d)Neither Statement II nor Statement III is correct
22. Q22.Energy

    With reference to 'Direct Air Capture', an emerging technology, which of the following statements is/are correct? I. It can be used as a way of carbon sequestration. II. It can be a valuable approach for plastic production and in food processing. III. In aviation, it can be a source of carbon for combining with hydrogen to create synthetic low-carbon fuel. Select the correct answer using the code given below.

    • a)I and II only
    • b)III only
    • c)I, II and III
    • d)None of the above statements is correct
23. Q23.Botany

    Consider the following pairs: Plant Description I. Cassava : Woody shrub II. Ginger : Herb with pseudostem III. Malabar spinach : Herbaceous climber IV. Mint : Annual shrub V. Papaya : Woody shrub How many of the above pairs are correctly matched?

    • a)Only two
    • b)Only three
    • c)Only four
    • d)All the five
24. Q24.Energy

    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
25. Q25.Aviation

    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
26. Q26.Chemistry

    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
27. Q27.Chemistry

    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
28. Q28.Chemistry

    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
29. Q29.Information Technology

    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. How many of the statements given above are correct?

    • a)Only one
    • b)Only two
    • c)All the three
    • d)None
30. Q30.Biotechnology

    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. III. They are used in treating viral infections like that of Nipah virus. 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
31. Q31.Chemistry

    Consider the following statements: Statement I: Some rare earth elements are used in the manufacture of flat television screens and computer monitors. Statement II: Some rare earth elements have phosphorescent properties. Which one of the following is correct in respect of the above statements?

    • a)Both Statement I and Statement II are correct and Statement II explains Statement I
    • b)Both Statement I and Statement II are correct but Statement II does not explain Statement I
    • c)Statement I is correct but Statement II is not correct
    • d)Statement I is not correct but Statement II is correct
32. Q32.Railway Technology

    Consider the following statements: I. Indian Railways have prepared a National Rail Plan (NRP) to create a 'future ready' railway system by 2028. II. 'Kavach' is an Automatic Train Protection system developed in collaboration with Germany. III. 'Kavach' system consists of RFID tags fitted on track in station section. Which of the statements given above are not correct?

    • a)I and II only
    • b)II and III only
    • c)I and III only
    • d)I, II and III
33. Q33.Space

    Consider the following space missions: I. Axiom-4 II. SpaDeX III. Gaganyaan How many of the space missions given above encourage and support micro-gravity research?

    • a)Only one
    • b)Only two
    • c)All the three
    • d)None
34. Q34.Defence

    With reference to India's defence, consider the following pairs: Aircraft type Description I. Dornier-228 : Maritime patrol aircraft II. IL-76 : Supersonic combat aircraft III. C-17 Globemaster III : Military transport aircraft How many of the pairs given above are correctly matched?

    • a)Only one
    • b)Only two
    • c)All the three
    • d)None
35. Q35.Space Technology

    GPS-Aided Geo Augmented Navigation (GAGAN) uses a system of ground stations to provide necessary augmentation. Which of the following statements is/are correct in respect of GAGAN? I. It is designed to provide additional accuracy and integrity. II. It will allow more uniform and high quality air traffic management. III. It will provide benefits only in aviation but not in other modes of transportation. Select the correct answer using the code given below.

    • a)I, II and III
    • b)II and III only
    • c)I only
    • d)I and II only