Explanation : 

Historical Reforms on Women’s Suffrage

The Montagu-Chelmsford Reforms of 1919 played a significant role in shaping the governance of British India, but contrary to popular belief, they did not extend voting rights to all women above the age of 21. These reforms introduced a system known as “dyarchy,” which aimed to increase Indian participation in government. However, the grant of suffrage to women was limited and subject to restrictions like property ownership, education, and marital status, rather than being a universal provision.

In contrast, the Government of India Act of 1935 made more substantial strides towards women’s political representation. This Act not only expanded the electorate but also reformed the legislative structure of British India. It marked a significant step in the political empowerment of women by providing for reserved seats in the legislature, although it continued to impose qualifications based on property and education.

Explanation : 

Treasury Bills and Government Bonds

Retail investors through a demat account can invest in ‘Treasury Bills’ and ‘Government of India Debt Bonds’ in the primary market. This is possible through platforms such as the ‘Retail Direct’ scheme launched by the Reserve Bank of India (RBI), which allows individuals to open a Gilt Securities Account (Retail Direct) for investing in government securities both in the primary and secondary markets.

Negotiated Dealing System-Order Matching (NDS-OM)

The ‘Negotiated Dealing System-Order Matching’ (NDS-OM) is a government securities trading platform of the RBI. It is an electronic trading platform that enables the trading of government bonds and T-Bills, and is utilized by a variety of market participants including banks and financial institutions.

Central Depository Services Ltd. (CDSL)

‘Central Depository Services Ltd.’ (CDSL) is not jointly promoted by the Reserve Bank of India and the Bombay Stock Exchange. Instead, CDSL was established by the Bombay Stock Exchange (BSE) along with other Indian financial institutions. The RBI does not have a direct involvement in the promotion or ownership of CDSL.

Explanation : 

Why Light-Years Measure Astronomical Distances Effectively

A light-year is a unit of distance that measures how far light travels in one year. Since light travels at a constant speed of approximately 299,792 kilometers per second (or about 186,282 miles per second) in a vacuum, it provides a consistent measure for astronomical distances.

Key Reasons for Using Light-Years

Consistency: The speed of light in a vacuum is one of the fundamental constants of nature and does not change. This constancy allows astronomers to use light-years as a reliable unit of measurement, knowing that it will always represent the same distance.

Universal applicability: The speed of light is the same throughout the universe (as far as we know), making light-years a universal unit that can be used by all astronomers, regardless of their location in the universe.

Comprehensible scale: The distances between stars and galaxies are so vast that using conventional units like kilometers or miles would result in impractically large numbers. A light-year provides a scale that is more manageable when discussing the vastness of space.

Relates to observation: When we look at the stars and other celestial objects, we are seeing them as they were in the past, because the light has taken time to travel to us. Measuring distances in light-years directly relates to the time it takes for that light to reach us, providing a sense of both distance and time.

Common Misconceptions

• Distances among stellar bodies do not change: This is not true; distances between stars and galaxies can change due to their motion through space and the expansion of the universe.
• Gravity of stellar bodies does not change: While the gravitational constant is indeed a fundamental constant, the gravity of individual stellar bodies can vary widely and does not provide a fixed reference for measuring distances.
• Light always travels in a straight line: While light generally travels in a straight line, it can be bent by gravity (gravitational lensing). However, this does not directly relate to why light-years are used as a unit of measurement.

Explanation : 

Triclosan

Triclosan is an antibacterial and antifungal agent that has been widely used in a variety of consumer products, including toiletries such as toothpaste, soaps, deodorants, and hand sanitizers. Its primary function in these products is to reduce or prevent bacterial contamination, thereby reducing the risk of infection and maintaining product integrity.

The Safety Concerns of Triclosan

Concerns about triclosan arise from studies that have shown it can disrupt hormones in animals and might contribute to the development of antibiotic-resistant bacteria. Due to these concerns, the U.S. Food and Drug Administration (FDA) issued a rule in 2016 that banned the use of triclosan (and several other antibacterial ingredients) in over-the-counter consumer antiseptic wash products, like liquid soap, foam soap, gel hand soap, bar soap, and body wash because manufacturers did not prove that the ingredients are both safe for long-term daily use and more effective than plain soap and water in preventing illness and the spread of certain infections.

Explanation : 

Bisphenol A (BPA) in Polycarbonate Plastics and Epoxy Resins

Bisphenol A (BPA) is a chemical compound that is primarily used in the production of polycarbonate plastics and epoxy resins. Polycarbonate is a type of plastic known for its strength, durability, and transparency, which makes it suitable for a wide range of applications, including the manufacture of water bottles, sports equipment, medical devices, and the lining of metal food cans.

The reason BPA is a key component in the manufacture of polycarbonate plastics is due to its chemical structure. BPA has two phenol functional groups, which are reactive and can be used to form the backbone of the polycarbonate polymer chain through a process known as polymerization. When BPA molecules react with phosgene (COCl₂) or with a carbonyl chloride-based compound in a condensation reaction, they form long chains of polycarbonate polymer.

Alternative Plastics and BPA Usage

The other plastics listed do not typically use BPA in their manufacturing processes:

1. Low-density polyethylene (LDPE) is made from the polymerization of ethylene and does not require BPA for its production.
2. Polyethylene terephthalate (PET) is made from the polymerization of ethylene glycol and terephthalic acid and does not include BPA in its structure.
3. Polyvinyl chloride (PVC) is made from the polymerization of vinyl chloride monomers and also does not contain BPA.

Health Concerns and BPA

BPA has become a cause for concern because it can leach out of plastics and into food and drinks, particularly when the plastic is heated or damaged. Studies have shown that BPA can mimic estrogen and other hormones in the body, potentially leading to health effects such as reproductive disorders, developmental problems, and other illnesses. As a result, many manufacturers and governments have taken steps to reduce the use of BPA in consumer products, especially those intended for food and drink storage.

Explanation : 

ACE2 in Viral Disease Spread

ACE2 stands for Angiotensin-Converting Enzyme 2. It is an enzyme that is attached to the outer surface (cell membranes) of cells in various organs such as the lungs, heart, kidney, and intestines. ACE2 has gained significant attention in the context of the spread of viral diseases, particularly due to its role as a receptor for the coronavirus responsible for COVID-19, known as SARS-CoV-2.

Receptor for SARS-CoV-2 : The spike protein of SARS-CoV-2 binds to the ACE2 receptor on the surface of human cells. This binding is the first step in the viral infection process, as it allows the virus to gain entry into the cell. Once inside, the virus can replicate and spread to other cells, leading to the development of COVID-19.

Viral Entry Point: Because ACE2 is expressed in various organs, it provides multiple potential entry points for the virus, which can lead to multi-organ infection and a range of symptoms associated with COVID-19.

Therapeutic Target: Understanding the interaction between ACE2 and the coronavirus spike protein has been crucial for developing therapeutic strategies, such as monoclonal antibodies that can block this interaction and prevent the virus from entering cells.

Genetic Research: Research into the variations in the ACE2 gene among different populations may provide insights into why some individuals are more susceptible to severe COVID-19 than others.

Explanation : 

Street Lighting: Sodium vs. LED Lamps

The comparison between sodium lamps and LED lamps for street lighting involves several factors, including the direction of light emission, lifespan, and color spectrum. Here’s a detailed explanation:

Direction of Light Emission

Sodium lamps are known for their 360-degree light emission, which requires the use of reflectors in streetlights. In contrast, LED lamps emit light directionally, enhancing their efficiency in street lighting applications.

Lifespan Comparison

LED lamps boast a longer lifespan than sodium lamps. While sodium lamps can last up to 24,000 hours, LEDs can last up to 100,000 hours, offering greater durability and cost-effectiveness over time.

Color Spectrum and Visibility

Sodium lamps produce a nearly monochromatic yellow light with poor color rendering, making it difficult to distinguish colors. LED lamps, however, provide a broad spectrum of visible light with excellent color rendering, which significantly improves night-time visibility and color distinction.

Explanation : 

Pressure Cooker Cooking Temperatures

The correct answer is “1 and 3 only,” which means that the temperature at which the food is cooked in a pressure cooker depends mainly upon the area of the hole in the lid and the weight of the lid.

Area of the Hole in the Lid

The area of the hole, or vent, in the lid of a pressure cooker is critical because it determines the pressure that can be maintained inside the cooker. A pressure cooker works by trapping steam inside, which increases the pressure and consequently raises the boiling point of water. The size of the hole is usually designed to allow just enough steam to escape to maintain a specific pressure, which correlates with a specific temperature. If the hole were larger, the pressure would be lower, and the temperature would be reduced.

Temperature of the Flame

While the temperature of the flame does affect how quickly the pressure cooker reaches the desired pressure, it does not directly determine the cooking temperature once the cooker has reached pressure. The cooking temperature is primarily set by the pressure inside the cooker, which is controlled by the design of the pressure valve (related to the area of the hole) and the weight on the lid.

Weight of the Lid

The weight of the lid, or more specifically, the weight of the pressure regulator that sits on the vent pipe, plays a direct role in controlling the pressure inside the cooker. The heavier the weight, the higher the pressure that can be maintained before steam is allowed to escape. This higher pressure results in a higher cooking temperature. In many pressure cookers, different weights can be used to achieve different pressures, which correspond to different cooking temperatures.

Official Answer by UPSC is c

Explanation : 

Rivers Originating from the Eastern Ghats

Brahmani River: is formed by the confluence of two rivers, the Sankh and the Koel, which rise from the Chota Nagpur Plateau and flow through the Eastern Ghats before merging.

Nagavali River: The Nagavali River originates from the Eastern Ghats in Odisha and flows through Odisha and Andhra Pradesh.

Subarnarekha River: The Subarnarekha River originates from the Chota Nagpur Plateau in Jharkhand and does not rise from the Eastern Ghats.

Vamsadhara River: The Vamsadhara River also originates from the Eastern Ghats in Odisha and flows through Odisha and Andhra Pradesh.

Based on the above information, the rivers that rise from the Eastern Ghats are the Nagavali and the Vamsadhara. Therefore, the correct answer is:

Explanation : 

Official Answer – Sutlej