UPSC Essentials | Daily subject-wise quiz : Science and Technology MCQs on stealth technology, Dual Frequency Synthetic Aperture Radar and more (Week 165)

3. Stealth objects are coated with metamaterials to increase the scattering of electromagnetic radiation.

Select the answer using the code given below:

(a) 1 only

(b) 2 and 3 only

(c) 1 and 2 only

(d) 1, 2 and 3

Relevance: Stealth technology is a key component of modern military aircraft, drones, naval platforms, and missile systems, making it important for Defence and Science and Technology preparation. Understanding stealth principles helps in tackling questions related to military modernisation, aerospace engineering, and strategic capabilities.

Explanation

— The Defence Ministry issued the Request for Proposal (RFP) for the indigenous fifth-generation Advanced Medium Combat Aircraft project to three shortlisted private bidders – Tata Advanced Systems, Larsen and Toubro-Bharat Electronics Limited, and a Bharat Forge-BEML-led consortium – officials confirmed to The Indian Express.

— Stealth technology encompasses aircraft geometric shaping, material engineering, the use of radar absorbent materials (RAM), and electromagnetic designs. Radar-absorbing materials are used to reduce radar cross sections (RCS) by absorbing electromagnetic radiation and thereby reducing reflected energy. Special radar-absorbing materials are necessary to absorb microwave energy, particularly in the low-frequency bands. Hence, statements 1 and 2 are correct.

— Stealth coatings are designed to diminish radar returns through absorption and RCS reduction. Hence, statement 3 is not correct.

Therefore, option (c) is the correct answer.

(Other Source: drdo.gov.in)

QUESTION 2

Consider the following statements:

1. Russia has successfully launched the Long March 12B.

2. It is mandatory for a country to issue airspace closure notices ahead of the mission.

3. The Long March 12B has been developed with reusability in both stages.

Which one of the following conclusions based on the above statements is correct?

(a) All three statements are correct.

(b) There are two correct statements, that include statement 1.

(c) There is only one correct statement.

(d) There is no correct statement.

Relevance: Space technology, reusable launch vehicles, and international space missions are increasingly appearing in UPSC Prelims through current affairs-based science and technology questions. Understanding developments in major space programmes of countries such as China, Russia, and the United States helps in tackling statement-based questions.

Explanation

— China has successfully launched the Long March 12B, a partially reusable rocket that bears several similarities to SpaceX’s Falcon 9, in a surprise maiden mission that deployed two internet satellites into orbit. Hence, statement 1 is not correct.

— The rocket lifted off on June 1 from the Jiuquan Satellite Launch Centre in the Gobi Desert. The launch drew attention because it took place without warning. China did not issue airspace closure notices ahead of the mission, a safety measure commonly used by launch operators before rocket launches. But they are not universally mandatory under an enforceable global requirement. Hence, statement 2 is not correct.

— The Long March 12B’s first flight carried two operational satellites for the Qianfan, or ‘Thousand Sails’ internet megaconstellation. The network is often compared to SpaceX’s Starlink satellite internet system. According to the China Aerospace Science and Technology Corporation (CASC), both satellites were successfully deployed into low Earth orbit.

— Designed as a two-stage rocket with a reusable first stage, the Long March 12B stands about 70 metres tall and is powered by nine engines on its booster stage. Like Falcon 9, it uses kerosene and liquid oxygen as propellants. Hence, statement 3 is not correct.

Therefore, option (d) is the correct answer.

QUESTION 3

Which of the following statements with regard to Black Boxes used in modern aircrafts is/are correct? (UPSC 2026)

1. They carry a beacon emitting red light pulses to facilitate underwater detection.

2. They record both the cockpit voice and flight data.

3. Their memory units are made using either stainless steel or titanium.

Select the answer using the code given below :

(a) 1 only

(b) 2 and 3 only

(c) 1 and 2 only

(d) 1, 2 and 3

Relevance: Black boxes are frequently discussed during aircraft accidents and investigations, making them an important current affairs-linked topic for Science and Technology in UPSC Prelims. The question appeared in UPSC 2026. The topic also helps in understanding broader themes related to aviation safety, accident investigation, and advancements in aerospace technology.

Explanation

— The black box, or aircraft flight recorder, has been around in some form since the 1930s, when French engineer François Hussenot originated a data recorder equipped with sensors that would optically project around 10 parameters onto a photographic film. The film ran continuously in a box constructed to prevent any light from entering it, lending it the name “black box”. The name has endured ever since, even though the external metal casing has always been orange, to help its speedy identification and retrieval.

— The invention of the box, however, is credited to Australian jet fuel expert David Ronald de Mey Warren, who was reportedly inspired by a miniature recorder he had seen at a trade fair. While analysing the mid-air explosion of the world’s first commercial jet aircraft, the British de Havilland Comet jetliners in 1953, he concluded that in-flight recordings could help analyse the events leading to the crash.

How do black boxes help understand plane crashes?

— Most aircraft today are mandatorily equipped with two black boxes, the cockpit voice recorder (CVR) and the flight data recorder (FDR). The CVR records radio transmissions and other sounds in the cockpit, including the conversations between the pilots and the engine noises. The FDR, on the other hand, records numerous technical details pertaining to the flight itself, such as altitude, airspeed, vertical acceleration, autopilot status, etc. Hence, statement 2 is correct.

— The recorders are stored inside a unit made of a strong material such as steel or titanium, and are insulated from extreme heat, cold, and wetness. These boxes are equipped towards the tail end of the aircraft, which usually sustains the least impact from a crash. Hence, statement 3 is correct.

— These recorders are equipped with a beacon that can send out ultrasound signals for 30 days, which becomes handy when planes crash into water bodies. However, in some cases, like the Malaysian Airlines MH370 flight, the recorders weren’t found.

Note: Aircraft black boxes are equipped with an Underwater Locator Beacon (ULB) that emits ultrasonic acoustic pings, not red light pulses. Hence, statement 1 is not correct.

Therefore, option (b) is the correct answer.

QUESTION 4

Which of the following items of defence hardware is/are manufactured in India? (UPSC 2026)

1. Su-30 MKI Fighter Jets

2. T-90 MK-III Tanks

3. Akula Class Submarine

Select the answer using the code given below :

(a) 1 and 2

(b) 1 and 3

(c) 1 only

(d) 2 only

Relevance: Defence indigenisation and self-reliance under India’s defence production ecosystem are recurring themes in UPSC Prelims. Awareness of fighter aircraft, tanks, submarines, missiles, and major defence acquisition programmes is important from both security and current affairs perspectives.

Explanation

— The Su-30MKI upgrade programme, also referred to as the Super Sukhoi programme, is a major midlife upgrade programme which can increase the service life of the multirole fighter by another 20 years.

— The Sukhoi Su-30 MKI is a twinjet multirole air superiority fighter designed by Russia’s Sukhoi and manufactured under licence in India by Hindustan Aeronautics Limited (HAL) for the Indian Air Force (IAF). Production: The jets are built at HAL’s factory in Ojhar, Nashik. While initially manufactured with Russian kits and technology, HAL has gradually enhanced the aircraft’s indigenous content. Hence, 1 is correct.

— The T-90 Mk-III Bhishma is a heavily upgraded license-produced derivative of the Russian T-90 tank made in India by the state-owned Heavy Vehicles Factory (HVF) in Avadi, Chennai. Hence, 2 is correct.

— The Indian Navy leases Russian-designed nuclear-powered attack submarines known as the Akula class. Hence, 3 is not correct.

— The Indian Navy already operates an Akula 2 class nuclear submarine, INS Chakra (previously known as K-152 Nerpa), which was leased by Russia for ten years and commissioned on April 4, 2012, after India paid for the ship’s construction and sea trials. India had been eager to lease a second nuclear submarine.

Therefore, option (a) is the correct answer.

QUESTION 5

With reference to the Dual Frequency Synthetic Aperture Radar (DFSAR), consider the following statements:

1. It is a microwave imaging instrument capable of studying the lunar surface and subsurface.

2. It was a part of Chandrayaan 3.

3. It uses L-band and S-band radar frequencies.

How many of the statements given above are correct?

(a) Only one

(b) Only two

(c) All three

(d) None

Relevance: Lunar exploration missions and their scientific payloads are important topics in Science and Technology, especially with India’s expanding space programme. Understanding radar technologies and their applications in planetary exploration helps in solving concept-based and current affairs-linked questions.

Explanation

— Scientists working with Isro and the Physical Research Laboratory have discovered new evidence suggesting the presence of subsurface water ice in permanently shadowed regions near the Moon’s south pole using data from Chandrayaan-2.

— The findings, published in the journal npj Space Exploration on May 6, are based on observations from Chandrayaan-2’s Dual Frequency Synthetic Aperture Radar (DFSAR), a microwave imaging instrument capable of studying the lunar surface and subsurface using L-band and S-band radar frequencies. Hence, statements 1 and 3 are correct.

— Using advanced radar polarimetric analysis, researchers identified radar signatures consistent with buried ice beneath the floors of four doubly shadowed craters in the lunar south polar region.

— The DFSAR instrument onboard Chandrayaan-2 is also significant because it became the first fully polarimetric synthetic aperture radar sent to study the Moon. Hence, statement 2 is not correct.

Therefore, option (b) is the correct answer.

Previous Daily Subject-Wise-Quiz

Daily Subject-wise quiz — History, Culture, and Social Issues (Week 156)

Daily subject-wise quiz — Polity and Governance (Week 165)

Daily subject-wise quiz —  Science and Technology (Week 164)

Daily subject-wise quiz — Economy (Week 164)

Daily subject-wise quiz — Environment and Geography (Week 164)

Daily subject-wise quiz – International Relations (Week 164)

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