UPSC Prelims 2023 Science and Technology questions: topic-wise weightage
UPSC Prelims 2023 asked 6 science and technology questions in GS Paper I, spread over 3 topics. See the science and technology weightage for 2023 below, then attempt each question with the official answer and an explanation.
Science and Technology 2023: questions by topic
- Biology, health and biotechnology2
- Space technology3
- Physics and chemistry in daily life; energy and nuclear technology1
Counted from the 6 questions on this page, tagged by topic in the Battle IAS PYQ bank.
Seeing 6 Science and Technology questions spread over 3 topics can feel overwhelming. That's exactly why the Battle IAS PYQ Book maps every question topic by topic, so you know what to study first. Download free sample
Biology, health and biotechnology 2
‘Wolbachia method’ is sometimes talked about with reference to which one of the following?
Answer (a) & explanation
The Wolbachia method is used to control viral diseases spread by mosquitoes (a). Wolbachia is a common bacterium found in many insects. When it is put into Aedes aegypti mosquitoes, it stops dengue, Zika and chikungunya viruses from multiplying inside them. Infected females pass it to their young, so it spreads through the wild mosquito population over time. Options (b), (c) and (d) are about crop residues, bioplastics and biochar, which have nothing to do with it.
Notice the results: the World Mosquito Program has cut dengue sharply in trial cities such as Yogyakarta in Indonesia. India's ICMR developed its own Wolbachia strains of Aedes mosquitoes in 2024. Another approach releases sterile male mosquitoes.
Answer as per the official UPSC answer key.
‘Microsatellite DNA’ is used in the case of which one of the following?
Answer (a) & explanation
Microsatellite DNA is used to study evolutionary relationships (a). Microsatellites are short DNA sequences, two to six letters long, repeated many times in a row, such as CACACA. The number of repeats varies a lot between individuals and populations. That makes them useful for DNA fingerprinting, paternity tests, wildlife forensics, population genetics and studying evolutionary relationships among species. Option (b) is about stem cells, option (c) about tissue culture and option (d) about clinical trials. "Satellite" here has nothing to do with space.
Notice India's use: the Wildlife Institute of India and CCMB's LaCONES lab use such markers to identify tiger individuals from scat and catch poachers. They also help breeding programmes avoid inbreeding.
Answer as per the official UPSC answer key.
Space technology 3
Consider the following actions :
- 1. Detection of car crash/collision which results in the deployment of airbags almost instantaneously
- 2. Detection of accidental free fall of a laptop towards the ground which results in the immediate turning off of the hard drive
- 3. Detection of the tilt of the smartphone which results in the rotation of display between portrait and landscape mode
In how many of the above actions is the function of accelerometer required?
Answer (c) & explanation
An accelerometer is needed in all three (c). An accelerometer, usually a tiny MEMS chip, senses changes in speed and the direction of gravity. Action 1 needs it: in a crash, it detects the sudden deceleration and fires the airbags within milliseconds. Action 2 needs it: when a laptop is in free fall, the sensor feels near-zero gravity and parks the hard drive heads to avoid damage. Action 3 needs it: it measures the tilt of a phone against gravity to switch the screen between portrait and landscape.
Notice its partners: a gyroscope measures rotation, and a magnetometer works like a compass. Together they power step counters, games and navigation when GPS drops. Smartwatches also use them for fall detection.
Answer as per the official UPSC answer key.
Consider the following pairs :
| 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
How many of the above pairs are correctly matched?
Answer (a) & explanation
Only one pair is correct (a). Pair 3 is right: pulsars are fast-spinning neutron stars, left when a massive star runs out of fuel and collapses in a supernova; they send out beams of radio waves like a lighthouse. Pairs 1 and 2 are swapped. Cepheids are pulsating stars that brighten and dim regularly; their period shows their true brightness, so they are used to measure cosmic distances. Nebulae are giant clouds of dust and gas, where new stars are born.
Notice that Henrietta Leavitt found the Cepheid period-brightness rule, and Edwin Hubble used it to show the universe is expanding. India's GMRT near Pune helps study pulsars, which act as precise cosmic clocks.
Answer as per the official UPSC answer key.
Which one of the following countries has its own Satellite Navigation System?
Answer (d) & explanation
Japan has its own satellite navigation system (d). Japan's Quasi-Zenith Satellite System (QZSS), called Michibiki, is a regional system that boosts GPS accuracy over Japan and the Asia–Oceania region. Australia (a), Canada (b) and Israel (c) rely on others' systems. There are four global systems: GPS (USA), GLONASS (Russia), Galileo (European Union) and BeiDou (China). There are two regional systems: Japan's QZSS and India's NavIC.
Notice India's NavIC (IRNSS) covers India and about 1,500 km around it. Some of its satellites lost their atomic clocks, and ISRO is launching the new NVS series, starting with NVS-01 in 2023. Phones now carry chips that use NavIC.
Answer as per the official UPSC answer key.
Physics and chemistry in daily life; energy and nuclear technology 1
Consider the following statements :
- 1. Carbon fibres are used in the manufacture of components used in automobiles and aircrafts.
- 2. Carbon fibres once used cannot be recycled.
Which of the statements given above is/are correct?
Answer (a) & explanation
Only statement 1 is correct (a). Statement 1 is right: carbon fibre composites are very strong and light, so they are used in aircraft such as the Boeing 787 and Airbus A350, in racing and electric cars, wind turbine blades and sports gear like rackets and bicycles. Lighter vehicles burn less fuel. Statement 2 is wrong: carbon fibres can be recycled. Processes such as pyrolysis, which burns away the resin, and solvolysis, which dissolves it, recover the fibres, though these are costly and the fibres come out shorter.
Notice India's push: carbon fibre is a strategic material for missiles and space vehicles, and India still imports most of it. ISRO and DRDO have built their own, and private firms are setting up plants.
Answer as per the official UPSC answer key.
All years by topic
Every question from 2011 to 2026, grouped by syllabus topic, with year-wise trends.