April 17 2024 Prelims Practice Questions (PPQs)

Correct

Explanation

Statement 1 is correct

• Kerogen is the portion of naturally occurring organic matter that is non-extractable using organic solvents i.e. it is insoluble in solvents.
• Kerogens are described as Type I, consisting of mainly algal and amorphous (but presumably algal) kerogen and highly likely to generate oil; Type II, mixed terrestrial and marine source material that can generate waxy oil; and Type III, woody terrestrial source material that typically generates gas.
• The types of kerogens present in a rock largely control the type of hydrocarbons generated in that rock.

Statement 2 is correct

• Kerogen represents about 90% of the organic carbon in sediments.
• It occurs in source rock and may expel hydrocarbons upon thermal cracking.
• Typical organic constituents of kerogen are algae and woody plant material.
• It consists of lighter as well as heavier hydrocarbons and acts like a precursor of oil and natural gas.
• Kerogens have a high molecular weight relative to bitumen, or soluble organic matter.
• Bitumen forms from kerogen during petroleum generation.

Answer: (c) Both 1 and 2; Difficulty Level: Medium

Correct

Explanation

Statement 1 is correct

• It is the world’s largest man-made lake and reservoir by volume.

  

Statement 2 is incorrect

• It is 200 kilometers downstream of Victoria Falls.
• The lake was filled following the completion of the Kariba Dam wall at its northeastern end, flooding the Kariba Gorge on the Zambezi River.
• It provides considerable electric power to both Zambia and Zimbabwe and supports a thriving commercial fishing industry.
• It is roughly estimated to be about 280 km long and 40 km at its widest. It covers an area of nearly 6,000 square kilometres.

Statement 3 is incorrect

• It lies approximately 1300 kilometers upstream from the Indian Ocean, along the border between Zambia and Zimbabwe.

  

• The Kariba Dam consists of a double-arch wall. It is 128 meters in height, 617 meters in length, 13 meters wide at its top, and 24 meters wide at the base.
• The wall extends across the Kariba gorge, creating a border crossing between Zambia and Zimbabwe.
• It took up to three years for the dam wall to be completed. Construction began on the 6th November, 1956, and was finished in 1959.

Answer: (b) Only two; Difficulty Level: Medium

Correct

Explanation

Statement 1 is correct

• The Men5CV Vaccine is designed to safeguard against five different strains of meningococcal bacteria. These bacteria can cause serious illnesses, including meningitis (inflammation of the membranes surrounding the brain and spinal cord) and septicemia (bloodstream infection).
• By targeting these specific strains, the vaccine helps prevent meningococcal disease, which can be life-threatening.
• The vaccine covers five serogroups of meningococcal bacteria: A, C, W, X, and Y.
• Each serogroup has distinct surface proteins (capsules), and the vaccine stimulates the immune system to recognize and fight these proteins.

Statement 2 is incorrect

• Men5CV Vaccine is recommended by the World Health Organization (WHO) to protect humans against five different strains of meningococcal bacteria. This vaccine and emergency vaccination campaigns contribute to the global stockpile of meningitis vaccines.

Answer: (a) 1 only; Difficulty Level: Medium

Correct

Explanation

Statement 1 is incorrect

• The Carbon-Carbon (C-C) nozzle is a remarkable advancement in rocket engine technology developed by the Vikram Sarabhai Space Centre (VSSC), part of the Indian Space Research Organisation (ISRO).
• The C-C nozzle promises to enhance the vital parameters of rocket engines, including thrust levels, specific impulse, and thrust-to-weight ratios.
• By leveraging advanced materials like Carbon-Carbon (C-C) Composites, VSSC has created a nozzle divergent with exceptional properties.
• This nozzle exhibits low density, high specific strength, and excellent stiffness, even at elevated temperatures.
• Its special anti-oxidation coating of Silicon Carbide extends operational limits in oxidizing environments.

Statement 2 is incorrect

• The C-C nozzle’s potential impact is significant, especially for ISRO’s workhorse launcher, the Polar Satellite Launch Vehicle (PSLV).
• Currently, the PSLV’s fourth stage (PS4) employs twin engines with nozzles made from Columbium alloy.
• By replacing these metallic divergent nozzles with C-C counterparts, a mass reduction of approximately 67% can be achieved.
• This substitution is projected to increase the payload capability of the PSLV by 15 kg, a notable enhancement
• The C-C nozzle features a special protective layer made of Silicon Carbide.
• This coating not only helps the nozzle withstand harsh conditions and high temperatures but also improves its resistance to corrosion.

Answer: (c) Both 1 and 2; Difficulty Level: Medium

Correct

Explanation

• Global Forest Watch (GFW) is an online platform that provides data and tools for monitoring forests.
• It was established by World Resources Institute (WRI), launched in 1997.
  • WRI is a research institute established in 1982 to promote environmentally sound and socially equitable development.
  • It is headquartered in Washington, D.C.
  • They organize their work around seven global challenges: Food, Forests, Water, Energy, Climate, the Ocean and Cities.
• It is free and simple to use, enabling anyone to create custom maps, analyze forest trends, subscribe to alerts, or download data for their local area or the entire world.
• It refers to tree cover when talking about forest extent, loss, and gain.
• Tree cover is a convenient metric for monitoring forest change because it is easily measurable from spaceusing freely available, medium-resolution satellite imagery.

Answer: (c) World Resources Institute (WRI); Difficulty Level: Medium

Correct

Explanation

• The case of Supriya Chakraborty and Another v. Union of India marks a watershed moment in the legal landscape of India.
• Beyond its immediate implications in the realm of reproductive rights and individual autonomy, this case reshaped broader societal narratives and legal paradigms, particularly concerning marriage norms and the rights of the LGBTQ+ community.
• The applicants tested the legitimacy of Section 4 (c) of the Special Marriage Act, 1954 on the ground that the arrangement oppresses same-sex couples by denying them advantages, for example, reception, surrogacy, and work and retirement benefits.
• Its significance reverberated far beyond the courtroom, sparking a cultural and legal shift that has begun to redefine the conventional understanding of marriage.
• LEGAL PROVISIONS: Articles 14, 15, 19, 21, and 25 of the Indian Constitution, Special Marriage Act of 1954, Hindu Marriage Act of 1955, Foreign Marriage Act of 1969.

Answer: (b) Rights to Queer Community; Difficulty Level: Medium

Correct

Explanation

Statement 1 is correct

• Ringwoodite is a fascinating mineral comes from olivine (another mineral) that exists in the Earth’s transition zone.
• Ringwoodite is polymorphous with forsterite, Mg2SiO4, and has a spinel structure.
• Spinel group minerals crystallize in the isometric system with an octahedral habit.
• Olivine is most abundant in the upper mantle, above about 410 km, the olivine polymorphs wadsleyite and ringwoodite are thought to dominate the transition zone of the mantle, a zone present from about 410 to 660 km depths.

  

• Ringwoodite is thought to be the most abundant mineral phase in the lower part of Earth’s transition zone. The physical and chemical property of this mineral partly determine properties of the mantle at those depths

Statement 2 is incorrect

• Ringwoodite can absorb water. But it can’t absorb water in liquid, solid or gas form!
• High temperatures and pressures don’t just transform olivine into ringwoodite. They also cause water molecules to split. This creates hydroxyl radicals (-OH).
• Pores in the ringwoodite absorb the hydroxyl radicals. This traps the broken-down water inside the mineral’s molecular structure.

Answer: (b) 2 only; Difficulty Level: Medium

Correct

Explanation

Statement 1 is correct

• Soil acidification is a natural process that occurs when hydrogen cations accumulate in the soil, leading to a reduction in soil pH.
• Chemically, this happens when a proton donor is introduced to the soil.
• The donor can be an acid, such as nitric acid, sulfuric acid, or carbonic acid. It can also be a compound like aluminium sulfate, which reacts in the soil to release protons.
• Causes:
  • Acid Rain: Rainfall is naturally acidic due to carbonic acid formation from carbon dioxide in the atmosphere. When rainfall has a lower pH than natural levels, it can rapidly acidify the soil. Precursors like sulfur dioxide and nitrogen oxides contribute to acid rain production.
  • Leaching of Base Cations: Acidic rainfall leaches essential base cations (such as calcium) from the soil, allowing aluminum and proton levels to increase.
  • Seasonal Effects: Nitric and sulfuric acids in acid rain and snow can impact forest soils differently, especially in regions with snow accumulation during winter. Nitric acid-rich snow meltwater can temporarily decrease drainage water pH.
  • Natural Processes: Soil acidification also occurs naturally as lichens and algae break down rock surfaces, releasing acids over time.

Statement 2 is incorrect

• This process can affect both the surface soil and subsoil.
• Soil acidification affects nutrient availability, cation leaching, soil structure instability, and metal toxicity.
• It impacts plant performance and soil biological properties.

Answer: (a) 1 only; Difficulty Level: Medium