Physics & Materials Science

Statement 1 is Correct: The Su-30 MKI Fighter Jets are manufactured in India. They are produced by Hindustan Aeronautics Limited (HAL) at its Nashik facility under a licensing and technology-transfer agreement with Russia's Sukhoi. Recent contracts for the jets feature over 60% indigenous content. Statement 2 is Correct: The T-90 MK-III Tanks (Bhishma) are manufactured in India. These main battle tanks are produced by the state-owned Armoured Vehicles Nigam Limited (AVNL) at the Heavy Vehicles Factory (HVF) in Avadi, Tamil Nadu, under a Russian license. The Indian Army recently began receiving the latest Mk-III variants from HVF. Statement 3 is Incorrect: The Akula Class Submarine is not manufactured in India. The Akula-class is a series of nuclear-powered attack submarines (SSNs) designed and built entirely in Russia. India does not manufacture them; rather, the Indian Navy has historically leased them from Russia (e.g., INS Chakra, leased in 2012 and returned in 2021) to train its crew and bolster its underwater capabilities. Therefore, the correct option is A.

Statement 1 is Incorrect: The Deep Ocean Mission (DOM) is a flagship initiative launched and implemented by the Ministry of Earth Sciences (MoES), Government of India, not the Ministry of Ports, Shipping and Waterways. Statement 2 is Correct: Matsya-6000 is an indigenous manned submersible vehicle developed by the National Institute of Ocean Technology (NIOT). It is specifically designed to carry 3 people (aquanauts) in a titanium alloy sphere to a depth of 6,000 meters for deep-sea exploration, including the study of marine biodiversity and the mining of rare minerals like polymetallic nodules. Statement 3 is Correct: Samudrayaan is India's first manned deep-sea ocean mission and is a primary sub-project under the broader Deep Ocean Mission. Therefore, option B is the correct answer.

Statement 1 is Incorrect: Black boxes are equipped with an Underwater Locator Beacon (ULB). When immersed in water, the ULB activates and emits an acoustic (ultrasonic) pulse (typically at 37.5 kHz) to guide sonar-equipped searchers. It does not emit light pulses, as light cannot travel effectively through deep ocean water. Statement 2 is Correct: The term "black box" collectively refers to two distinct recording devices (which are sometimes combined into a single unit): the Cockpit Voice Recorder (CVR), which records radio transmissions and sounds in the cockpit, and the Flight Data Recorder (FDR), which records technical flight parameters such as altitude, airspeed, heading, and acceleration. Statement 3 is Correct: The data is stored inside a highly protected component called the Crash-Survivable Memory Unit (CSMU). To survive extreme impact (up to 3,400 Gs), deep-sea pressure, and intense fire (up to 1,100°C), the CSMU's outer armor is manufactured using heavy-duty stainless steel or titanium, layered with thermal insulation. Therefore, option B is the correct answer.

Statement 1 is Correct: The primary goal of stealth technology is to minimize an object's Radar Cross-Section (RCS), making it appear as small as a bird or insect on enemy screens. This is achieved through geometric shaping (to deflect waves away from the source) and by coating the surface with Radar Absorbing Materials (RAM), which absorb electromagnetic radar energy and dissipate it as heat. Statement 2 is Correct: Stealth objects are not completely invisible. Their shapes and RAM coatings are typically optimized to defeat high-frequency radars (like X-band) used for precise weapons targeting. However, they can often be detected by low-frequency radars (such as VHF and UHF bands). The longer wavelengths of these specific frequencies resonate with the aircraft's physical dimensions, allowing detection, though they lack the resolution required for a missile lock. Statement 3 is Incorrect: Metamaterials are artificially engineered structures with unique electromagnetic properties. In advanced stealth applications, they are used to decrease or eliminate radar scattering, not increase it. They achieve this by either perfectly absorbing the electromagnetic radiation or by bending and redirecting the waves smoothly around the object (electromagnetic cloaking) so that no signal scatters back to the radar receiver. Increasing scattering would make the object highly visible, defeating the purpose of stealth. Therefore, the correct option is C.

John Clarke is the correct answer. He was born in Cambridge, United Kingdom, and was jointly awarded the 2025 Nobel Prize in Physics for the discovery of macroscopic quantum mechanical tunneling in an electric circuit. At the time of the announcement, he was a Professor Emeritus at the University of California, Berkeley, which is an American university. Michel H. Devoret is incorrect. Although he shared the 2025 Nobel Prize in Physics and was affiliated with American universities (Yale University and UC Santa Barbara), he was born in France, not the UK. Richard Robson is incorrect. While he was born in Yorkshire, England (UK) and won the 2025 Nobel Prize in Chemistry, his academic affiliation at the time of the award was the University of Melbourne, which is an Australian university, not an American one. Joel Mokyr is incorrect. He won the 2025 Nobel Prize in Economic Sciences and was a professor at Northwestern University (an American university), but he was born in Leiden, Netherlands, not the UK. Therefore, Option C is the correct answer.

Statement 1 is Correct: In December 2025, the Bureau of Indian Standards (BIS) notified India's first dedicated national standard for bomb disposal systems, officially designated as IS 19445:2025. Statement 2 is Correct: The standard establishes comprehensive guidelines for evaluating bomb disposal equipment (such as bomb blankets, baskets, and inhibitors) against blast loads and splinter effects. A primary objective is to bring uniformity to testing and procurement, thereby improving the safety, reliability, and interoperability of equipment across various deploying agencies (e.g., Armed Forces, CAPFs, NSG, and State Police). Statement 3 is Incorrect: The standard was developed indigenously by BIS at the request of the Union Ministry of Home Affairs (MHA) and the DRDO’s Terminal Ballistic Research Laboratory (TBRL). There is no record of collaboration with Russian entities (such as the 30th Central Scientific Research Institute). 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 the specific threat profiles and operational realities faced by Indian forces. Therefore, the correct option is C.

✅ Statement I: Correct
Rare earth elements like europium, terbium, and yttrium are essential in flat TV screens and monitors due to their role in producing vibrant colors and enhancing display quality. ✅ Statement II: Correct
These elements exhibit phosphorescence—absorbing energy and slowly emitting light—which is key to their use in color reproduction and brightness in displays. Relationship:
Statement II explains why rare earth elements are crucial in displays, confirming the reason behind Statement I. Therefore, both statements are correct and related.

CL-20, HMX, and LLM-105 are chemical substances known for their use as high-energy explosives in military weapons. * ✅CL-20: A powerful explosive with high energy density. * ✅ HMX: A well-known military explosive used in various munitions. * ✅ LLM-105: A newer explosive with similar high performance. All three are explosives used in military weapons.

In lithium-ion batteries, the cathode is typically made of materials that include Cobalt, Lithium, and Nickel, depending on the chemistry used. * ✅I. Cobalt: Used in cathodes like LCO and NMC. * ❌ II. Graphite: Used in the anode, not the cathode. * ✅III. Lithium: Core element in cathode materials (like LCO, LFP). * ✅IV. Nickel: Found in cathode types like NMC and NCA. Three of the four are used in cathodes. Alternatively, you can use mnemonic CoLiNi to remember Cathode forming materials.

* Statement 1 is incorrect: This is typically done using X-ray scanners or advanced imaging technologies like millimeter wave scanners, not traditional radar. * Statement 2 is correct: Radars, specifically weather radars, are commonly used to monitor precipitation. They can detect rain, snow, and other weather conditions by bouncing radio waves off precipitation particles. * Statement 3 is correct: Radars can be used to track the migration of birds and other animals. They are often used in ornithological studies to monitor bird migration patterns.