Solution (b)

Explanation:

• While autonomous underwater vehicles (AUVs) are used in anti-submarine warfare to detect enemy submarines and map the ocean floor, the CALM System is not related to underwater or anti-submarine operations
• A CALM (Canister Launched Loiter Munition) System typically comes in a sealed, ready-to-use canister, making it quickly deployable. Once launched, the munition can be guided to its target, combining the surveillance capabilities of a drone with the offensive power of a missile. Loiter munitions are essentially “kamikaze drones” that can hover over an area for an extended period and strike when a suitable target is located. (Option (b) is correct)
• Laser-based defence systems exist to neutralize incoming projectiles (for example, the HEL (High Energy Laser) systems), but the CALM System described is not a directed-energy weapon nor does it utilize lasers to intercept incoming fire.
• Landmine detection and clearing technology often involves mapping techniques, ground-penetrating radar, or robotic systems to ensure safe clearance.

Solution (c)

Explanation:

• The Naval Innovation and Indigenisation Organisation (NIIO) was formally launched by the Indian Navy in August 2020. The NIIO was established to drive the Navy’s efforts toward self-reliance (Aatmanirbhar Bharat) in defence manufacturing and to foster an ecosystem that nurtures innovation.

One of the key objectives of NIIO is to streamline the Indian Navy’s interaction with industry and academia, including startups and MSMEs. By doing so, it seeks to accelerate the process of idea generation, prototyping, and product development. This approach encourages joint research, technology development, and capability enhancement in a transparent and user-friendly manner. (Option (c) is correct)

Solution (a)

Explanation:

• The CTBT is a multilateral treaty that prohibits all nuclear explosions, regardless of their purpose—whether for military or peaceful applications. It aims to constrain the development of nuclear weapons and promote nuclear disarmament. The treaty was adopted by the United Nations General Assembly on 10 September 1996 and aims to ensure a legally binding global ban on nuclear testing. (Option (a) is correct)
• The CTBT explicitly bans all nuclear explosions, whether for military or peaceful purposes. There are no exceptions to this prohibition under the treaty’s framework. The Partial Test Ban Treaty (PTBT) of 1963 allowed peaceful nuclear explosions, but the CTBT closed this loophole.
• India has neither signed nor ratified the CTBT. India has raised concerns about the treaty’s discriminatory nature, as it does not require nuclear weapons states to disarm and instead institutionalizes their nuclear privileges. India insists on a universal, non-discriminatory, and verifiable disarmament framework.

Solution (b)

Explanation:

• Project Kusha is a defence initiative led by the Defence Research and Development Organisation (DRDO) to develop a long-range air defence system by 2028-29. The system aims to detect and neutralize advanced enemy threats such as cruise missiles, stealth fighters, and drones at long ranges.
• Project Kusha envisions the development of three types of interceptor missiles with ranges of 150 km, 250 km, and 350 km. These missiles will be integrated with advanced long-range surveillance and fire control radar systems, providing a robust multi-layered air defence capability. (Option (b) is correct)
• Project Kusha is being led by the Defence Research and Development Organisation (DRDO), not Hindustan Aeronautics Limited (HAL). While HAL plays a crucial role in defence aviation, the development of air defence systems and missiles falls under DRDO’s purview.

Solution (b)

Explanation:

• The Light Combat Helicopter (LCH), developed by Hindustan Aeronautics Limited (HAL), falls in the 5-8 tonne class. It was designed specifically to meet the needs of high-altitude combat operations, conceptualized after the 1999 Kargil conflict. It is a dedicated combat helicopter, capable of operating in extreme altitudes, unlike multipurpose helicopters.
• The LCH incorporates radar-absorbing material to reduce its radar signature, enhancing its stealth capabilities. This is a significant feature that increases survivability in combat scenarios by making it harder for enemy radars to detect. (Option (b) is correct)
• The LCH has a combat radius of 500 km, not 5000 km. A combat radius of 500 km aligns with its operational role for high-altitude and close-combat missions, which require agility and shorter range.
• The LCH is powered by two French-origin Shakti engines, which are co-developed by HAL and Turbomeca (now Safran Helicopter Engines). While the engines are manufactured in India by HAL, they are not fully Indian in origin.
• The LCH is the only attack helicopter in the world capable of operating at altitudes as high as 5,000 m (16,400 ft), making it ideal for high-altitude conflict zones like the Siachen Glacier and the Himalayan border areas.
• The LCH is armed with advanced weaponry, including anti-tank guided missiles, air-to-air missiles, rockets, and a 20 mm nose gun. It also has features like crash-proof structure, countermeasure dispensing systems, and a pressurized cabin for NBC protection.

Solution (d)

Explanation:

• Agni-1 is capable of carrying both conventional and nuclear warheads, with a payload capacity of up to 1,000 kg. This dual capability makes it a versatile and strategic weapon in India’s missile arsenal.
• The Agni-1 missile is a single-stage, solid-fuelled missile. Solid-fuel technology offers rapid deployment and greater stability compared to liquid-fuel systems, making it an efficient and reliable ballistic missile.
• Agni-1 is designed as a strategic weapon in India’s missile program. Its role is aligned with India’s nuclear doctrine of credible minimum deterrence and the ability to deter regional adversaries.

The Agni-1 missile has a range of 700–900 km, not above 2500 km. Its payload capacity is approximately 1,000 kg, far below the stated 5,000 kg. The range and payload described in this option are closer to those of Agni-IV or Agni-V missiles, which are designed for intermediate or long-range targets. (Option (d) is incorrect)

Solution (a)

Explanation:

• The Pinaka Multi-Barrel Rocket Launcher (MBRL) system is developed by the Defence Research and Development Organisation (DRDO). It is an indigenous system designed to provide artillery support with high mobility and rapid-fire capabilities.
• Pinaka can launch rockets up to 75 km (enhanced version) and is used by the Indian Army. This system is a testament to DRDO’s focus on strengthening India’s artillery capabilities with indigenous technology. (Option (a) is correct)
• The Tejas Mk-2 jet is being developed by Hindustan Aeronautics Limited (HAL), not DRDO. HAL is responsible for the production and development of this advanced version of the Light Combat Aircraft (LCA) Tejas. 
• While DRDO, through its subsidiary Aeronautical Development Agency (ADA), was involved in the initial design of the Tejas LCA, the Mk-2 variant is HAL’s project. Tejas Mk-2 is designed as an advanced multirole fighter with improved avionics, weapon capacity, and range.
• The Dhruv Advanced Light Helicopter (ALH) is developed by Hindustan Aeronautics Limited (HAL), not DRDO. HAL is India’s premier aerospace manufacturer and has been the primary organization responsible for helicopter design and production. Dhruv is a versatile utility helicopter used by the Indian Army, Air Force, Navy, and Coast Guard for transport, reconnaissance, and rescue missions.

Solution (c)

Explanation:

• The Kris Gopalakrishnan committee was tasked with recommending measures to regulate non-personal data and enhancing India’s cybersecurity framework.
• The Homi Bhabha Committee, established in the mid-20th century, laid the foundation for India’s nuclear energy program and the establishment of the Department of Atomic Energy (DAE).
• The Vijay Raghavan panel, a nine-member government-appointed committee, recently submitted its report to address concerns about DRDO’s functioning. The panel’s mandate includes identifying delays in defence R&D projects, inefficiencies in resource allocation, and methods to improve innovation and project delivery. DRDO plays a key role in India’s indigenous defence production, and its reform is essential for achieving self-reliance under Atmanirbhar Bharat. (Option (c) is correct)
• The N Chandrasekaran Task Force was formed to evaluate the adoption of Artificial Intelligence (AI) in the defence sector. The task force provided recommendations on how AI can enhance operational capabilities, automate defence production, and strengthen India’s military edge.

Solution (b)

Explanation:

• HAPS operates in the stratosphere (18–20 km above Earth’s surface), not the mesosphere (50–85 km). It complements low-earth orbit (LEO) satellites but cannot exceed their coverage in terms of altitude.
• HAPS is solar-powered, allowing it to stay airborne for weeks, months, or even years. Unlike satellites, which require expensive rocket launches, HAPS is deployable and retrievable at significantly lower costs.

HAPS can hover or remain stationary over a fixed location in the stratosphere, which is a key advantage over conventional UAVs, whose range and endurance are limited by fuel or battery capacity. (Option (b) is correct)

Solution (a)

Explanation:

• A Multiple Independently Targetable Re-entry Vehicle (MIRV) is a ballistic missile payload that can deliver multiple nuclear warheads to several distinct targets. Once the missile reaches space, the warheads can be deployed and guided (to a degree) individually toward separate targets. (Option (a) is correct)
• A single MIRV-equipped missile can release multiple warheads. Each warhead then follows its own trajectory to strike different targets, thereby multiplying the missile’s overall destructive capability and complicating enemy missile defence efforts. The U.S. Minuteman III ICBM, for instance, can carry multiple warheads, each targeted at different objectives.
• The United States and the Soviet Union (now Russia) were the pioneers in developing and deploying MIRV technology during the Cold War. China has also developed MIRV capabilities in more recent years. 
• Beyond these three, other nuclear-armed states such as the United Kingdom and France have developed submarine-launched ballistic missiles (SLBMs) with MIRV capabilities. India has also indicated advancements in MIRV technology for its Agni missiles, though full operational deployment status may vary.

Solution (b)

Explanation:

• The Positive Indigenisation List (PIL) is a set of equipment and platforms that the Indian armed forces will procure only from domestic sources after a specified timeline. This is part of the government’s strategy to reduce imports, promote self-reliance, and strengthen the indigenous defence manufacturing ecosystem.
• The PIL is not limited to public sector enterprises like the Defence Public Sector Undertakings (DPSUs) or the Ordnance Factory Board (now the 7 new DPSUs). It aims to foster indigenisation within the entire Indian defence industry ecosystem, which includes both public and private sector manufacturers. In fact, the private sector is actively encouraged to participate, innovate, and supply items listed in the PIL.

The Department of Military Affairs (DMA), headed by the Chief of Defence Staff (CDS), is responsible for ensuring coordination and reforms in defence procurement and indigenisation initiatives. The Positive Indigenisation Lists are indeed notified and promulgated through the DMA as part of the broader ‘Aatmanirbhar Bharat’ (self-reliant India) defence push. (Option (b) is correct)

Solution (a)

Explanation:

• India commissioned its first SSBN, INS Arihant, into service in August 2016. The second SSBN, INS Arighaat, was commissioned at the end of August 2024, according to the given information. Thus, as of now, India has two operational SSBNs: INS Arihant and INS Arighaat. (Option (a) is correct)
• There are two types of nuclear-powered submarines:
  • SSBN (Ship Submersible Ballistic Nuclear): These are ballistic missile submarines primarily designed for strategic deterrence by carrying submarine-launched ballistic missiles (SLBMs).
  • SSN (Ship Submersible Nuclear): These are nuclear-powered attack submarines, often referred to as “hunter-killers,” as their primary role is to hunt and destroy enemy submarines and surface ships, and perform other tactical missions.
• SSBNs are not generally called “hunter-killers”; that term applies to SSNs (Nuclear Attack Submarines).
• India’s first SSBN is INS Arihant, commissioned in 2016. INS Arighaat is the second SSBN. Thus, INS Arighaat is not the first SSBN.

Solution (c)

Explanation:  

• The Anti-Personnel Landmines Convention,1997 is an international agreement that aims to eliminate the use, production, stockpiling, and transfer of anti-personnel landmines. It is commonly referred to as the Ottawa Convention or Anti-Personnel Mine Ban Treaty.
• Under the treaty’s provisions, States Parties agree to destroy their stockpiles of anti-personnel mines within four years and clear mined areas under their jurisdiction or control within ten years. 
• This comprehensive approach addresses both the future threat (production and transfer) and the existing legacy of contamination (stockpiles and minefields). Many countries have successfully destroyed millions of stockpiled mines, showcasing the treaty’s tangible humanitarian and disarmament impact.
• The Anti-Personnel Landmines Convention (also known as the Ottawa Convention) applies exclusively to anti-personnel mines. It defines anti-personnel mines as devices designed to explode due to the presence, proximity, or contact of a person, thus primarily targeting humans.
• The text of the treaty clearly focuses on anti-personnel mines. Its central goal is to address the humanitarian crisis caused by these mines—tools that indiscriminately injure or kill civilians long after conflicts end. The treaty does not ban or regulate anti-vehicle (often called anti-tank) mines. (Option (c) is correct)
• The treaty entered into force on March 1, 1999, less than two years after it was concluded, reflecting widespread global support. Such a swift entry into force is noteworthy in international law, indicating strong international consensus on the humanitarian imperative to outlaw these weapons. As of now, 164 States are Parties to the Convention, showcasing near-universal acceptance, although some major powers have not joined. This participation level underscores the treaty’s role in shaping global norms against the use of anti-personnel mines. 

Solution (d)

Explanation:  

• While the Ministry of Education focuses on e-learning and digital platforms like DIKSHA and SWAYAM, it is not responsible for launching Eklavya. DIKSHA is a digital infrastructure for school education offering e-content to teachers and students while SWAYAM is an online learning platform offering Massive Open Online Courses (MOOCs) for higher education.
• The Ministry of Finance manages fiscal policies, budgeting, and economic regulations but is not involved in defence education platforms. Platforms like PRAGATI for monitoring government projects or initiatives related to financial inclusion (e.g., PMJDY, UPI).
• The Ministry of Commerce does not focus on defence-related training or education platforms. Focus areas include Ease of Doing Business, Start-Up India, and export promotion initiatives. Platforms like GeM (Government e-Marketplace) and INSTANT focus on trade facilitation, not education or defence.
• The Ministry of Defence launched the “Eklavya” online learning platform specifically designed for the Indian Army. It enhances professional education and training for Indian Army officers. It is part of the Decade of Transformation (2023-2032) initiative.

It is created by Bhaskarcharya National Institute of Space Applications and Geoinformatics (BISAG-N), Gandhinagar and includes 96 courses hosted by 17 Category ‘A’ Training Establishments of the Indian Army. (Option (d) is correct)

Solution (b)

Explanation:  

• INS Tushil belongs to the Talwar Class, which is part of the Krivak III-class frigates under Project 1135.6. It is the 7th frigate in this series, following three Talwar-class and three Teg-class frigates. The Talwar Class frigates are known for their stealth features, advanced weapon systems, and multipurpose roles.
• INS Tushil is not indigenously developed at the Mazagaon Docks. It was built in Russia under a 2016 contract between the Indian Government and JSC Rosoboronexport, a Russian defense exporter. While India is focusing on indigenous shipbuilding through initiatives like the Nilgiri-class frigates and the Vikrant aircraft carrier, INS Tushil was built in Russia.

A frigate is indeed a versatile warship designed for escort, patrolling, and combat operations. Frigates play a key role in protecting maritime assets, escorting larger ships, and ensuring the safety of sea lines of communication. Their flexibility makes them an indispensable part of modern navies, especially for nations like India with extensive maritime borders. (Option (b) is correct)

Solution (a)

Explanation:  

• Hybrid warfare involves the simultaneous use of kinetic (physical/military) and non-kinetic (psychological, cyber, economic, and informational) tactics to achieve strategic objectives.  (Option (a) is correct)
• Kinetic Warfare refers to traditional military operations, such as armed combat, bombings, and troop deployment.
• Non-Kinetic Warfare includes cyber-attacks, disinformation campaigns, economic coercion, and psychological warfare aimed at destabilizing the enemy without physical conflict.

Solution (a)

Explanation:  

• Pinaka Rocket System is an indigenously developed multiple rocket launcher system by DRDO, Pinaka is a key defence export of India. It has been exported to countries like Armenia, showcasing India’s capability in producing advanced artillery systems.
• BrahMos Missile System is a jointly developed by India and Russia, the supersonic cruise missile is a flagship export product. Recently, it was exported to the Philippines, marking a significant milestone in India’s defence exports.  (Option (a) is correct)
• T-90 Tanks are of Russian origin and imported by India under license. As a result, they are not part of India’s defence exports.

Heron UAVs are Israeli-made drones imported by India for surveillance and thus not exported by India.

Solution (a)

Explanation:  

• Hypersonic weapons are broadly classified into two types:
  • Hypersonic Glide Vehicles: These are launched via a rocket and then glide through the atmosphere at hypersonic speeds, following unpredictable paths.
  • Hypersonic Cruise Missiles: These use advanced scramjet engines to sustain hypersonic speeds during cruise flight within the atmosphere. (Option (a) is correct)
• Hypersonic Cruise Missiles do not follow a fixed flight path. Unlike ballistic missiles, they are highly maneuverable and can adjust their trajectories during flight, making them harder to intercept and detect.
• Hypersonic weapons have been used in live conflicts. Russia used its Kinzhal hypersonic missile in the Ukraine conflict in 2022, marking one of the first uses of hypersonic weapons in warfare.

Solution (c)

Explanation:  

• The ADITI (Acing Development of Innovative Technologies with iDEX) scheme explicitly aims to promote innovations in critical and strategic defence technologies. This aligns with India’s focus on advancing its defence ecosystem and fostering technological independence.
• While start-ups are eligible for grants under the ADITI scheme, the grant-in-aid of up to Rs 25 crore is specifically for research, development, and innovation endeavours in defence technology, not for all purposes.

The scheme explicitly aims to develop 30 deep-tech critical and strategic technologies during the 2023-24 to 2025-26 period. This is a key objective under the iDEX framework to strengthen India’s defence innovation ecosystem. (Option (c) is correct)

Solution (d)

Explanation:  

• Rocket launches result in various emissions depending on the type of propellant used. Significant emissions include black carbon, water vapor, and Aluminium oxide, which have notable environmental impacts.
• While CO can be a byproduct of incomplete combustion, it is not a significant emission from rocket launches. The combustion processes in rocket engines are designed for high efficiency, leaving minimal amounts of CO.
• Black carbon (soot) is released from rocket engines, especially those using kerosene-based fuels like RP-1. It accumulates in the upper atmosphere, contributing to global warming and altering atmospheric dynamics. Rockets like the Falcon 9 (SpaceX) release black carbon particles that stay in the atmosphere for extended periods.
• Water vapor is a major emission, particularly from rockets using liquid hydrogen and liquid oxygen (LH2/LOX) as propellants. It accumulates in the stratosphere, impacting the ozone layer and contributing to global warming. Space Shuttle launches released large quantities of water vapor. 

Rockets using solid propellants emit aluminium oxide, which forms tiny particles. These particles can reflect sunlight, affect radiative forcing, and harm the ozone layer. Solid rocket boosters, such as those used in the Space Shuttle, emit aluminium oxide as a major byproduct. (Option (d) is correct)

Solution (b)

Statement Analysis:

Context: China’s coast guard accused the Philippines of deliberately crashing one of its ships into a Chinese vessel near Sabina Shoal, a new flashpoint in the increasingly alarming territorial disputes between the countries in the South China Sea.

Hence option b is correct.

Solution (c)

Statement Analysis:

Context: Two scientists have flagged what they have called evidence of “problematic behaviour” in multiple scientific papers co-authored by Mandyam Srinivasan, emeritus professor of visual neuroscience at Queensland University, Brisbane. The papers are concerned with the honeybee waggle dance, a mode of communication between bees that plays a crucial role in pollination.

Honeybees live in colonies with one queen running the whole hive. Worker honeybees are all females and are the only bees most people ever see flying around outside of the hive. They forage for food, build the honeycombs, and protect the hive. Honeybees perform a waggle dance for others of their kin to indicate the direction and the distance to a source of their food. Hence option c is correct.

Solution (c)

Statement Analysis:

Context: India and Malaysia decided to upgrade ties to a ‘Comprehensive Strategic Partnership’ during talks between the Prime Minister and Malaysian Prime Minister as part of a visit aimed at moving beyond several years of tensions over several issues. 

• The existing Enhanced Strategic Partnership between India and Malaysia which was established in 2015, was upgraded to a Comprehensive Strategic Partnership in 2024. Hence statement 1 is correct.
• BRICS is an intergovernmental organization comprising Brazil, Russia, India, China, South Africa, Iran, Egypt, Ethiopia, and the United Arab Emirates.
• The members of the ASEAN are Brunei, Burma, Cambodia, Indonesia, Laos, Malaysia, Philippines, Singapore, Thailand, and Vietnam.
• Malaysia is not a member of the BRICS and India is not a member of the ASEAN. Hence statement 2 is incorrect.
• India has noted Malaysia’s designation of 2026 as Visit Malaysia Year.
• India will establish an Ayurveda Chair at Universiti Tunku Abdul Rahman in Malaysia to promote traditional medicine education and research. Hence statement 3 is correct.

Solution (d)

Statement Analysis:

Context: India is on its way to achieving its target of blending 20% of petrol with ethanol by 2025-26, going by the milestones on blending percentages crossed so far and the increase in ethanol production capacity.

• Ethanol is an organic compound that is a clear, colourless, flammable liquid. Hence statement 1 is correct.
• It is one of the principal biofuels, which is naturally produced by the fermentation of sugars by yeasts or via petrochemical processes such as ethylene hydration.
• Ethanol blending can reduce India’s oil imports and increase its energy self-reliance. Hence statement 2 is correct. 
• The Ethanol Blending Programme (EBP) is aimed at reducing the country’s dependence on crude oil imports, cutting carbon emissions, and boosting farmers’ incomes.
• Ethanol is a less polluting fuel and offers equivalent efficiency at a lower cost than petrol. Hence statement 3 is correct.

India has set a target of blending 20% of petrol with ethanol by 2025-26. Hence statement 4 is incorrect.

Solution (b)

Statement Analysis:

Context: In a novel double manoeuvre, the JUICE probe will use the gravity of the moon to swing towards the earth and then use the earth’s gravity to slow down.

• Jupiter Icy Moons Explorer (JUICE) mission is to explore Jupiter and its three large moons – Callisto, Europa, and Ganymede. These moons are of particular interest because they may harbour conditions that could support life. Hence statement 1 is incorrect.
• It is the first-ever lunar-Earth flyby combined with the first-ever double gravity assist manoeuvre.
• JUICE Mission has been initiated by the European Space Agency (ESA). Hence statement 2 is correct.
• It was launched in 2023 and will reach Jupiter and its moons by 2031, after an eight-year journey.

Solution (b)

Statement Analysis:

Context: The President of India, Smt Droupadi Murmu presented the National Geoscience Awards-2023 to 21 geoscientists at a ceremony held at Rashtrapati Bhavan Cultural Centre.

• The National Geoscience Awards are the most prestigious national awards in the field of geosciences established by the Ministry of Mines. Hence statement 1 is correct.
• It is a symbol of recognition and appreciation for exceptional individuals and organizations who have demonstrated excellence, dedication, and innovation in the realm of geosciences.
• Any citizen of India with a significant contribution in any field of geosciences is eligible for the award. Hence statement 2 is correct.
• Its objective is to honour both teams and individuals for extraordinary achievements and outstanding contributions in various fields of geosciences. Hence statement 3 is incorrect.
• It is conferred every year in three categories – the National Geoscience Award for Lifetime Achievement, the National Geoscience Award, and the National Young Geoscientist Award. Hence statement 4 is incorrect.

Note:

• Prof. Dhiraj Mohan Banerjee received the Lifetime Achievement Award for his pioneering work in phosphorites and Precambrian geology.
• Dr. Ashutosh Pandey was honoured as the National Young Geoscientist for his research on the Eastern Dharwar Craton.

Test explained

Solution (b)

Statement Analysis:

Context: Karnataka Chief Minister has urged the union government to clear the decks for increasing the height of the Almatti dam by issuing a notification of the award of Justice Brijesh Kumar Krishna River Water Disputes Tribunal, enabling the riparian States to utilise additional allocation of waters.

Hence option b is correct.

Solution (b)

Statement Analysis:

Context: The Indian Prime Minister visited Poland, the first visit by an Indian Prime Minister to Poland in 45 years. 

• Poland shares borders with seven countries. They are Germany, Slovakia, the Czech Republic, Lithuania, Belarus, Ukraine, and Russia. Hence statement 1 is incorrect.
• Poland is a parliamentary republic with a prime minister who is the head of government and a president who is the head of state. 
• Its capital city is Warsaw. Hence statement 2 is correct.
• Polish is its official language.
• Its major mountain ranges are the Carpathians and Sudetens. Hence statement 3 is correct.
• Its major rivers are Vistula and Oder.

Solution (c)

Statement Analysis:

Context: Recently, the Prime Minister claimed that India created “eight crore new jobs in the last three to four years”. The Prime Minister was using data from the India-KLEMS database hosted by the Reserve Bank of India (RBI). 

• The India-KLEMS Database is an academic exercise financed by the Reserve Bank of India (RBI). Hence statement 1 is correct.
• KLEMS stands for Capital (K), Labour (L), Energy (E), Material (M), and Services (S).
• The RBI does not directly collect data on any inputs, including employment. Instead, it sources data from official sources like the Central Statistics Office, Census of India, Annual Survey of Industries, and Periodic Labour Force Surveys (PLFS).
• It is used to measure industry-level total factor productivity (TFP). It is considered a measure of input efficiency in producing output by mainstream economists. Hence statement 2 is correct.

Solution (c)

Explanation: 

The author opines that ‘Caste is a form of social stratification characterized by endogamy and hereditary transmission of a lifestyle.’

Solution (a)  

Explanation: 

Issue 1 is incorrect. The passage mentions subsidized electricity which can be subsidized either directly by the government through its reserve or cross-subsidy. The passage nowhere mentions the source of subsidy, so we cannot assume it.  

Issue 2 is incorrect. The passage mentions the depletion of groundwater but it does not necessarily mean excess use of water. We do not know the source of excess water; it can be surface water or groundwater. Also, even limited water usage may lead to depletion of groundwater.  

Issue 3 is correct. The voltage instability may be one of the components of poor power quality which is mentioned in the passage. 

Solution (c)
Explanation:

Let us assume that he spent x percent on constructing the boundary.
Amount spent on floor work = 12×27000/100 (∵ His overall budget is Rs. 27000)
Amount spent on painting work = 28×27000/100
Amount spent on boundary construction = x × 27000/100
Left amount = Rs. 8100
According to the question,
(12×27000/100) + (28×27000/100) + (x × 27000/100) + 8100 = 27000
⟹ (27000/100) (12+28+x) = 27000 – 8100
⟹ (27000/100) (40+x) = 18900
⟹ 40+x = (18900×100)/27000
⟹ 40+x = 70
⟹ x = 30, i.e. 30%
Thus, Sonu spent 30% on construction of the boundary around the house.
Hence, option (c) is the correct answer.
Alternate Method:
Let’s calculate the percent amount left.
Amount left = (8100/27000) × 100 = 30%
Spend on painting = 28%
Spend on floor work = 12%
Let percentage amount spent on construction of boundary around the house be y%.
According to the question,
30+28+12+y = 100
Or y = 30%
Thus, Sonu spent 30% on construction of boundary around the house.
Hence, option (c) is the correct answer.

Solution (d)

Explanation: 

For minimum number of rooms required, we have to maximize the number of participants in each room. 

Maximum possible number of participants in each room = HCF (36, 60, 72) = 12 

So, Minimum number of rooms required = 36/12 + 60/12 + 72/12 = 3 + 5 + 6 = 14

Solution (d)

Explanation: 

Let the two numbers be 5x and 9x. 

HCF of 5x and 9x = x 

So, x = 14

 Sum of the two numbers = 5x + 9x = 14x = 14 × 14 = 196 Hence, option (d) is correct.