UPSC IAS Archives

31. With reference to the Indian economy, “Collateral Borrowing and Lendin

With reference to the Indian economy, “Collateral Borrowing and Lending Obligations” are the instruments of :

[amp_mcq option1=”Bond market” option2=”Forex market” option3=”Money market” option4=”Stock market” correct=”option3″]

This question was previously asked in

UPSC IAS – 2024

Collateral Borrowing and Lending Obligations (CBLO) were money market instruments introduced by the Clearing Corporation of India Ltd (CCIL) in 2003. CBLO represented an obligation by a borrower to return the borrowed funds at a specified future date and an obligation by a lender to return equivalent securities deposited as collateral by the borrower. It allowed market participants (like banks, financial institutions, mutual funds) to borrow and lend funds for short durations (typically overnight) against eligible securities held in electronic form. This function places CBLO firmly within the domain of the money market, which deals with short-term debt instruments.

CBLO was a short-term borrowing and lending instrument used in the Indian financial market with eligible securities as collateral.

CBLO was a significant instrument in the Indian money market for cash management and meeting reserve requirements until it was discontinued and replaced by the Tri-Party Repo (TREPS) system facilitated by CCIL in 2018-2019. TREPS serves a similar function as CBLO but with an added third party (CCIL or another clearing house) guaranteeing the settlement.

32. “Membrane Bioreactors” are often discussed in the context of which one

“Membrane Bioreactors” are often discussed in the context of which one of the following ?

[amp_mcq option1=”Assisted reproductive technologies” option2=”Drug delivery nanotechnologies” option3=”Vaccine production technologies” option4=”Wastewater treatment technologies” correct=”option4″]

This question was previously asked in

UPSC IAS – 2024

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Membrane Bioreactors (MBRs) are a technology used extensively in wastewater treatment. An MBR system combines a biological treatment process (such as activated sludge) with a membrane filtration step. The membranes are used to separate treated water from the activated sludge, effectively replacing the secondary clarifier and tertiary filtration found in conventional wastewater treatment plants. This allows for a higher concentration of biomass in the biological reactor, leading to more efficient treatment and producing high-quality effluent.

MBRs integrate biological treatment with membrane filtration for improved separation and treatment efficiency in wastewater management.

MBRs are particularly useful for treating municipal and industrial wastewater where space is limited, or high effluent quality is required, such as for water reuse applications. They offer advantages like smaller footprint, better effluent quality, and reduced sludge production compared to conventional systems.

33. Recently, the term “pumped-storage hydropower” is actually and appropr

Recently, the term “pumped-storage hydropower” is actually and appropriately discussed in the context of which one of the following ?

[amp_mcq option1=”Irrigation of terraced crop fields” option2=”Lift irrigation of cereal crops” option3=”Long duration energy storage” option4=”Rainwater harvesting system” correct=”option3″]

This question was previously asked in

UPSC IAS – 2024

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Pumped-storage hydropower (PSH) is a type of hydroelectric energy storage. It is used to balance energy supply and demand on the electricity grid. During periods of low electricity demand (e.g., at night), surplus electricity (often from renewable sources like solar or wind, or excess baseload power) is used to pump water from a lower reservoir to an upper reservoir. When electricity demand is high, the stored water is released from the upper reservoir, flowing back down through turbines to generate electricity. This process is designed for storing large amounts of energy for relatively long durations (hours to days), making it a form of long duration energy storage.

The primary purpose of pumped-storage hydropower is to store electrical energy and release it when needed, acting as a large-scale battery for the power grid.

While dams and reservoirs are involved, the focus of PSH is energy storage and grid stability, not irrigation or rainwater harvesting directly, although reservoirs can serve multiple purposes. Its role in integrating intermittent renewable energy sources into the grid is becoming increasingly important.

34. Which one of the following is the exhaust pipe emission from Fuel Cell

Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen ?

[amp_mcq option1=”Hydrogen peroxide” option2=”Hydronium” option3=”Oxygen” option4=”Water vapour” correct=”option4″]

This question was previously asked in

UPSC IAS – 2024

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Fuel Cell Electric Vehicles (FCEVs) powered by hydrogen generate electricity through an electrochemical process where hydrogen reacts with oxygen from the air. The primary chemical reaction in a hydrogen fuel cell is 2H₂ + O₂ → 2H₂O. This reaction produces water (H₂O) and energy (electricity and heat). The water produced is expelled from the vehicle, typically as water vapour, which is essentially steam.

The fundamental output of a hydrogen fuel cell, besides electricity and heat, is water.

FCEVs are considered zero-emission vehicles at the point of use because their only tailpipe emission is water vapour, unlike internal combustion engines that emit various pollutants and greenhouse gases. The environmental impact of hydrogen fuel cell technology depends significantly on how the hydrogen fuel itself is produced (e.g., from renewable sources or fossil fuels).

35. In which of the following are hydrogels used ? Select the correct answ

In which of the following are hydrogels used ?
Select the correct answer using the code given below :

Controlled drug delivery in patients
Mobile air-conditioning systems
Preparation of industrial lubricants

[amp_mcq option1=”1 only” option2=”1 and 2 only” option3=”2 and 3 only” option4=”1, 2 and 3″ correct=”option4″]

This question was previously asked in

UPSC IAS – 2024

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The question asks in which of the listed activities hydrogels are used. Hydrogels are three-dimensional networks of hydrophilic polymers that can absorb large amounts of water or biological fluids. Their unique properties make them useful in various applications.
1. Controlled drug delivery in patients: Hydrogels are extensively used in drug delivery systems. Drugs can be incorporated into the hydrogel matrix and released in a controlled manner as the hydrogel swells or degrades, allowing for sustained or targeted drug release. This is a well-established application.
2. Mobile air-conditioning systems: Hydrogels can be used in certain types of cooling systems, particularly those involving moisture absorption and evaporation. For instance, they can be incorporated into evaporative cooling pads or desiccant systems for moisture removal, which is a component in some air conditioning or cooling technologies, including potentially mobile or portable systems exploring energy efficiency or alternative cooling methods. While not in traditional compressor-based ACs, they are used in specific advanced or niche cooling applications.
3. Preparation of industrial lubricants: Certain hydrogels exhibit excellent lubricating properties, especially in aqueous environments. They can reduce friction between surfaces and are explored or used as lubricants in various industrial applications, particularly in machinery and biomedical devices where traditional oil-based lubricants are unsuitable. This is an established application.
Based on the known uses of hydrogels, all three activities are valid applications.

Hydrogels are versatile materials due to their biocompatibility, flexibility, and high water content, making them suitable for applications ranging from biomedical engineering and agriculture to environmental science and industrial processes.

Besides the listed applications, hydrogels are also used in areas such as tissue engineering (as scaffolds for cell growth), wound dressings (to maintain a moist environment), contact lenses, diapers and sanitary napkins (as superabsorbents), agriculture (for water retention in soil), and sensing (as responsive materials). The ability of hydrogels to respond to various stimuli (like temperature, pH, light) further expands their utility in smart systems like responsive drug delivery or sensors.

36. Consider the following aircraft : Rafael MiG-29 Tejas MK-1 How ma

Consider the following aircraft :

Rafael
MiG-29
Tejas MK-1

How many of the above are considered fifth generation fighter aircraft ?

[amp_mcq option1=”Only one” option2=”Only two” option3=”All three” option4=”None” correct=”option4″]

This question was previously asked in

UPSC IAS – 2024

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The question asks how many of the listed aircraft are considered fifth-generation fighter aircraft. Fifth-generation fighter aircraft are characterized by several key features, including stealth technology, supercruise capability (sustained supersonic flight without afterburners), high maneuverability, advanced avionics, high data-fusion capabilities, and network-centric warfare capabilities.
Let’s examine the listed aircraft:
– Rafael: The Dassault Rafale is a French twin-engine, canard delta wing, multirole fighter aircraft. It is widely considered a 4.5 generation fighter, incorporating advanced technologies and capabilities that bridge the gap between 4th and 5th generation aircraft, but it lacks the full-spectrum stealth required for true 5th generation status.
– MiG-29: The Mikoyan MiG-29 is a Soviet/Russian twin-engine jet fighter aircraft developed in the 1970s. It is widely considered a 4th generation fighter.
– Tejas MK-1: The HAL Tejas is an Indian single-engine, delta wing, light multirole fighter. The Tejas MK-1 is considered a 4th generation fighter aircraft. Subsequent planned variants (like Tejas MK-2 or the AMCA) are expected to incorporate more advanced features.
None of the aircraft listed (Rafael, MiG-29, Tejas MK-1) are classified as true fifth-generation fighter aircraft. Examples of fifth-generation fighters include the Lockheed Martin F-22 Raptor, Lockheed Martin F-35 Lightning II, Sukhoi Su-57, Chengdu J-20, and Shenyang FC-31/J-31.
Therefore, none of the aircraft listed are fifth-generation fighter aircraft.

Fighter aircraft generations are a classification system used to categorize jet fighters based on their technological capabilities and historical development. The key characteristics of 5th generation fighters represent a significant leap in performance, situational awareness, and survivability compared to previous generations, primarily driven by stealth and advanced sensor fusion.

Aircraft like the Rafale, Eurofighter Typhoon, and Boeing F/A-18E/F Super Hornet are often referred to as 4.5 generation fighters because they incorporate some, but not all, features of 5th generation aircraft, particularly advanced avionics, sensors, and limited stealth features, but lack full-aspect stealth and often supercruise capabilities. This transitional category highlights the continuous evolution of fighter technology.

37. Consider the following activities : Identification of narcotics on p

Consider the following activities :

Identification of narcotics on passengers at airports or in aircraft
Monitoring of precipitation
Tracking the migration of animals

In how many of the above activities can the radars be used ?

[amp_mcq option1=”Only one” option2=”Only two” option3=”All three” option4=”None” correct=”option3″]

This question was previously asked in

UPSC IAS – 2024

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The question asks in how many of the listed activities radars can be used. Radar (Radio Detection and Ranging) systems use radio waves to detect objects, determine their location, speed, and other characteristics.
1. Identification of narcotics on passengers at airports or in aircraft: Advanced radar-based scanners, particularly millimeter-wave scanners, are used in airport security for screening passengers. These scanners can detect concealed objects, including weapons and potentially other items like large quantities of narcotics, underneath clothing. So, radar can be used in this activity.
2. Monitoring of precipitation: Weather radar is a fundamental tool in meteorology used to detect, locate, and track precipitation (rain, snow, hail). It estimates the intensity and type of precipitation and predicts its movement. So, radar is used in this activity.
3. Tracking the migration of animals: Radar is widely used in biological research, particularly in ornithology and entomology, to study the migration patterns of birds and insects. Weather radar systems often detect large flocks of birds or insect swarms, and specialized biological radars are also used for more detailed tracking. So, radar can be used in this activity.
Since radar can be used in all three listed activities, the correct answer is “All three”.

Radar technology has diverse applications across various fields beyond its traditional use in military surveillance and air traffic control, including weather monitoring, remote sensing, security screening, and ecological studies.

Different types of radar systems are optimized for specific tasks and targets. For example, Doppler radar is used to measure the velocity of targets like precipitation particles or vehicles, while Synthetic Aperture Radar (SAR) is used for high-resolution imaging of the Earth’s surface. The versatility of radar technology stems from its ability to penetrate certain materials (like clothing or clouds) and operate day or night regardless of visibility.

38. Which one of the following is synthesised in human body that dilates b

Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow ?

[amp_mcq option1=”Nitric oxide” option2=”Nitrous oxide” option3=”Nitrogen dioxide” option4=”Nitrogen pentoxide” correct=”option1″]

This question was previously asked in

UPSC IAS – 2024

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The question asks for a substance synthesized in the human body that dilates blood vessels and increases blood flow.
Nitric oxide (NO) is a molecule produced by cells in the endothelium (lining of blood vessels) and other tissues. It is a potent vasodilator, meaning it causes the smooth muscles in the walls of blood vessels to relax, leading to increased diameter and blood flow. This process is crucial for regulating blood pressure and blood flow to different parts of the body.
Nitrous oxide (N₂O), also known as laughing gas, is an anesthetic and analgesic gas used in medicine but is not synthesized in the human body for vasodilation.
Nitrogen dioxide (NO₂) and Nitrogen pentoxide (N₂O₅) are oxides of nitrogen that are primarily environmental pollutants and industrial chemicals, not molecules synthesized endogenously in the human body for physiological functions like vasodilation.
Therefore, Nitric oxide is the correct answer.

Nitric oxide (NO) acts as a signaling molecule in the cardiovascular system, promoting vasodilation by activating guanylate cyclase, which leads to the relaxation of vascular smooth muscle cells. This mechanism is important for regulating blood pressure and tissue perfusion.

NO plays various other roles in the body, including neurotransmission, immune response, and muscle function. The discovery of NO’s role as a signaling molecule in the cardiovascular system was awarded the Nobel Prize in Physiology or Medicine in 1998. Medications like nitroglycerin, used to treat angina (chest pain), work by releasing NO, which dilates coronary arteries. Sildenafil (Viagra) also works by enhancing the effects of NO on blood vessels.

39. Consider the following statements : Statement-I : Giant stars live muc

Consider the following statements :
Statement-I :
Giant stars live much longer than dwarf stars.
Statement-II :
Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.
Which one of the following is correct in respect of the above statements ?

[amp_mcq option1=”Both Statement-I and Statement-II are correct and Statement-II explains Statement-I .” option2=”Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I” option3=”Statement-I is correct, but Statement-II is incorrect” option4=”Statement-I is incorrect, but Statement-II is correct” correct=”option4″]

This question was previously asked in

UPSC IAS – 2024

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The question asks about the lifespan and nuclear reactions in giant stars compared to dwarf stars.
Statement-I: “Giant stars live much longer than dwarf stars.” This statement is incorrect. Giant stars, being more massive than dwarf stars (like our Sun, a G-type dwarf), have much stronger gravitational forces. This results in higher temperatures and pressures in their cores, which accelerates the rate of nuclear fusion. Although they have more fuel, they burn it at a vastly higher rate, leading to significantly shorter lifespans compared to dwarf stars. Dwarf stars, with their slower rate of fusion, can live for billions or even trillions of years.
Statement-II: “Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.” This statement is correct. As explained above, the higher core temperatures and pressures in giant stars lead to a much higher rate of nuclear fusion reactions (converting hydrogen to helium) compared to dwarf stars. This high reaction rate is responsible for their high luminosity.
Statement I is incorrect, and Statement II is correct. Statement II actually explains *why* Statement I is incorrect (higher reaction rate leads to shorter lifespan). Therefore, Option D is the correct choice.

A star’s lifespan is primarily determined by its mass and luminosity (rate of energy output, which is proportional to the rate of nuclear reactions). More massive stars have more fuel but burn it much faster due to higher core temperatures and pressures, resulting in shorter lives. Less massive stars burn their fuel slowly and live much longer. Giant stars are typically more massive and much more luminous than dwarf stars.

Stars evolve through different stages, including dwarf phases, giant phases (like red giants or supergiants), and eventually remnant stages (like white dwarfs, neutron stars, or black holes), depending on their initial mass. The term “dwarf star” usually refers to main-sequence stars (like the Sun), while “giant star” refers to later evolutionary stages after the star has exhausted the hydrogen in its core and expanded significantly.

40. With reference to radioisotope thermoelectric generators (RTGs), consi

With reference to radioisotope thermoelectric generators (RTGs), consider the following statements :

RTGs are miniature fission reactors.
RTGs are used for powering the onboard systems of spacecrafts.
RTGs can use Plutonium-238, which is a by-product of weapons development.

Which of the statements given above are correct ?

[amp_mcq option1=”1 and 2 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option2″]

This question was previously asked in

UPSC IAS – 2024

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The question is about radioisotope thermoelectric generators (RTGs). Let’s analyze the statements:
Statement 1: “RTGs are miniature fission reactors.” This statement is incorrect. RTGs generate heat through the natural radioactive decay of a radioisotope (like Plutonium-238, Americium-241, Strontium-90), not nuclear fission (which involves splitting atoms). The heat from this decay is then converted into electricity using thermoelectric devices (based on the Seebeck effect).
Statement 2: “RTGs are used for powering the onboard systems of spacecrafts.” This statement is correct. RTGs are commonly used as power sources for spacecraft, particularly for deep-space missions (like Voyager, Cassini, Curiosity rover) where solar power is insufficient due to distance from the sun, or for missions operating in environments with limited sunlight (like lunar landers or polar rovers).
Statement 3: “RTGs can use Plutonium-238, which is a by-product of weapons development.” This statement is correct. Plutonium-238 (Pu-238) is a commonly used radioisotope in RTGs due to its appropriate half-life (about 87.7 years) and high energy density. While Pu-238 is not used in nuclear weapons, it is often produced as a by-product during the reprocessing of nuclear fuel from reactors, which can be part of the broader nuclear fuel cycle that might also produce materials for weapons. Specifically, Pu-238 is produced by irradiating neptunium-237. While not directly from weapons development, its production is linked to the nuclear industry infrastructure. The phrasing “by-product of weapons development” is somewhat imprecise but reflects the connection to the nuclear complex. Given the context of UPSC exams often presenting simplified connections, this statement is generally considered correct in this context.
Based on the analysis, statements 2 and 3 are correct, and statement 1 is incorrect.

RTGs are reliable, long-lasting power sources suitable for applications where maintenance is impossible and solar power is not viable. They convert heat from radioactive decay into electricity using thermoelectric converters, with no moving parts, making them highly durable.

The main advantage of RTGs is their longevity and ability to operate in harsh environments. However, they produce relatively low power output compared to nuclear reactors and pose safety concerns regarding the potential release of radioactive material in case of accidents. Plutonium-238 has been the preferred fuel due to its specific characteristics, but its limited availability has led to research into alternative isotopes like Americium-241.