UPSC 2024 Prelims Questions with Answers

Explanation

Statement I is correct: Rainfall plays a key role in weathering rocks through both physical and chemical processes. For instance rainfall water seeps into cracks, causing rocks to expand and contract. Over time, this weakens the rock structure. Similarly, In colder regions, rainwater freezes inside crevices and expands. This leads to cracks and eventually breaks the rock apart. Heavy rainfall also washes away loose particles, speeding up erosion. Chemically, rainwater reacts with minerals in the rock, causing slow decomposition and dissolution. Over time, these processes break down and lead to weathering of rocks.

Statement II is correct: Rainwater absorbs carbon dioxide (CO₂) from the atmosphere, forming a weak acid solution known as carbonic acid (H₂ CO₃). This acidic rainwater reacts with minerals in rocks, leading to chemical weathering, particularly in limestone and carbonate rocks, which dissolve in acidic conditions. This process is responsible for the formation of karst landscapes, caves, and sinkholes in limestone regions.

Statement III is correct: Rainwater absorbs oxygen (O₂) from the atmosphere, which plays a crucial role in oxidation reactions in rocks containing iron and other reactive minerals. Oxygen reacts with iron-rich minerals (e.g., magnetite, pyrite) in rocks to form iron oxides (rust), which weakens the rock structure. Both Statement-II (CO₂ in rainwater) and Statement-III (O₂ in rainwater) are correct. They both explain Statement-I, as they contribute to rock weathering through chemical processes like carbonation and oxidation.

Explanation

Hydrogels are three-dimensional polymer networks that can absorb and retain large amounts of water while preserving their structure. With their biocompatibility, flexibility, and customizable properties, they are widely utilized across various applications.

Option 1 is correct: Hydrogels have a porous, water-attracting structure that allows them to expand and contract in response to stimuli. This makes them ideal for controlled drug delivery, ensuring precise and sustained release in liquid environments.

Option 2 is incorrect: Hydrogels are not commonly used in mobile air-conditioning systems. Air-conditioning relies on compressors, refrigerants, and heat exchangers, and though materials with moisture retention might play a minor auxiliary role (like evaporative cooling pads), hydrogels are not a standard component in these systems.

Option 3 is incorrect: Hydrogels do not serve as specific base materials or additives in conventional industrial lubricants. Industrial lubricants typically rely on oils, greases, and synthetic compounds designed for reducing friction and wear. Hydrogels are not chemically or mechanically suited for this purpose. Note: UPSC has given Option(a) as an official answer.

Explanation

Statement 1 is incorrect: The Pradhan Mantri Surakshit Matritva Abhiyan (PMSMA) guarantees a minimum package of antenatal care (ANC) services only during pregnancy (second and third trimesters). However, it does not provide health care services for six months post-delivery.

Statement 2 is correct: Under PMSMA, private sector doctors (specialists like gynecologists, radiologists, and physicians) can volunteer to provide free maternal health services at government health facilities on the 9th of every month. This public-private partnership aims to improve access to quality maternal health services.

Explanation

A volcano is an opening or rupture in the Earth’s crust through which molten rock (magma), gases, and ash escape from beneath the surface. When magma reaches the surface, it is called lava. Volcanic eruptions can shape mountains and islands, affecting both the environment and climate. Example:

Mount Etna(Italy), Kilauea (USA) The materials that reach the Earth’s surface in volcanoes include: lava flows pyroclastic debris volcanic bombs ash and dust gases such as nitrogen compounds sulphur compounds minor amounts of chlorine, hydrogen and argon etc.

Explanation

Statement 1 is incorrect: The correct age group for enrollment is 18 to 40 years, not 21 to 40 years.

Statement 2 is correct: The contribution varies based on the age of the beneficiary at the time of joining the scheme. For example, an 18-year-old contributes 55 per month, while a 40-year-old contributes 200 per month.

Statement 3 is correct: After attaining 60 years of age, the subscriber is entitled to a monthly pension of ‘3,000.

Statement 4 is incorrect: Family pension is applicable only to the spouse (50% of the pension amount, i.e., ‘1,500 per month after the subscriber’s death). Unmarried daughters are not included in the family pension provision.

Explanation

Option 1 is correct: Donyi Polo Airport, Itanagar is the first greenfield airport in Arunachal Pradesh. The airport is suitable for all weather day operations.

Option 2 is correct: Since 2019, nearly 6 Greenfield airports namely, Kalaburagi, Orvakal (Kurnool), Sindhudurg, Itanagar, Kushinagar and Mopa have been operationalised, out of which Kushinagar and Mopa airports are International airports.

Option 3 is incorrect: Airport Authority of India has undertaken development/ expansion of airports in Port Blair (Andaman & Nicobar Islands), Vijayawada and Tirupati (Andhra Pradesh), Itanagar and Tezu (Arunachal Pradesh). Thus, Vijayawada airport is not a greenfield project.

Explanation

Stars are classified based on their size, mass, and brightness into categories such as giant stars and dwarf stars. Giant stars are massive, highly luminous stars that burn They are often in the later stages of stellar evolution. Dwarf stars, on the other hand, are smaller, less luminous, Red dwarfs, the most common type, can burn for trillions of years, while white dwarfs are the remnants of low to medium-mass stars after they exhaust their nuclear fuel.

Statement I is incorrect: Giant stars have much shorter lifespans than dwarf stars. Giant stars burn fuel quickly because of their high mass and energy, while red dwarf stars use fuel slowly, allowing them to last billions or even trillions of years.

Statement II is correct: Giant stars have much higher core temperatures and pressures, leading to faster nuclear fusion rates compared to dwarf stars. This high rate of fusion results in a shorter lifespan.

Explanation

The Government of India Act was passed by the British parliament in 1935 and came into effect in 1937. It was based on a report by a Joint Select Committee, led by Lord Linlithgow, set up the two houses of the British parliament. Some of the key features of the Act were:

The creation of a ‘Federation of India’ that consisted of two levels: a central executive and parliament, and below it, provinces and princely states. Hence, Statement 1 is correct. It discarded the ‘dyarchy’ system at the provincial level and allowed for the emergence of popularly elected provincial legislatures. Dyarchy was introduced at the central level, key subjects like defence and foreign affairs were under the direct control of the Governor General. Hence, Statement 2 is incorrect. A federal court was established. The franchise was expanded to 14% of the population from 3%. Separate electorates were provided for Muslims, Sikhs and others, but not to Depressed Classes. The governor enjoyed critical emergency powers.

Explanation

Note: Vermin category listed in Schedule V of the Wild-life Protection Act, 1972 has been removed after the Wildlife Protection Amendment Act 2022, as now there are only 4 schedules in WPA. Hence the answer is subject to considerations made by the Commission.

Statement 1 is correct: The Indian Flying Fox is placed under the "vermin" category in the Wild Life (Protection) Act, 1972 due to its destructive tendencies towards fruit farms.

Statement 2 is incorrect: Bats are the only flying mammals in the world, and the Indian Flying Fox is one of the largest. The species, Pteropus giganteus, also called the Great Indian Fruit Bat, eats fruits, feeding on the juice, and helps in seed dispersion and pollination, making them an integral part of the ecosystem.

Explanation

Emissions that lead to high concentrations of SO₂ generally also lead to the formation of other SOx. The largest sources of SO₂ emissions are from fossil fuel combustion at power plants and other industrial facilities. EPA’s national ambient air quality standards for SO₂ are designed to protect against exposure to the entire group of sulfur oxides (SOx). SO₂ is the component of greatest concern and is used as the indicator for the larger group of gaseous sulfur oxides (SOx). Other gaseous SOx (such as SO₃) are found in the atmosphere at concentrations much lower than SO₂.