Previous Year UPSC Questions

Explanation

Option (b) is correct: Chromium is added to iron to produce stainless steel and other high-performance alloys. It provides resistance to oxidation and high temperatures while also increasing hardness and abrasion resistance. Chromium’s ability to form a protective oxide layer makes it essential for producing steel that can withstand harsh conditions. Options (a), (c) and (d) are incorrect:

Aluminium is used for lightweight and corrosion-resistant alloys but not for high-temperature or abrasion resistance. Nickel primarily enhances toughness and corrosion resistance but does not directly improve abrasion resistance as much as chromium. Tungsten contributes to high-temperature strength and wear resistance, especially in tool steels, but chromium is the primary alloying element for the application.

Explanation

Micronutrients are essential elements required by plants in very small quantities (typically less than 100 mg/ kg of plant dry matter). Despite their minimal requirement, these nutrients play a critical role in various physiological and biochemical processes necessary for plant growth and development. Sodium is not considered an essential micronutrient for most plants. It may play a role in some specific plants, such as C₄ plants, but it is not universally required as a micronutrient. Other important micronutrients are Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), Chlorine (Cl), Nickel (Ni).

Explanation

Most international agencies that fund development programs in India through intergovernmental bilateral agreements primarily provide:

Technical Assistance: Many agencies offer expertise, knowledge sharing, and capacity-building support to help implement development projects effectively. Soft Loans: A significant portion of funding comes in the form of soft loans, which are required to be paid back but with low interest rates and long repayment periods. These loans are often concessional and designed to support development without imposing a heavy financial burden. Grants: Some agencies provide grants, which do not need to be repaid. These are typically used for social sector projects like health, education, and poverty alleviation. Only few agencies provide food assistance in some cases (e.g., during emergencies or specific programs), it is not the primary form of support from most international agencies.

Explanation

Ankiya Nat is a traditional one-act play of Assam, introduced by Sankaradeva and Madhavdev (15th-16th century AD). It is an opera-style performance depicting Lord Krishna’s life, featuring a Sutradhar (narrator), Gayan-Bayan Mandali (musicians), and masks for expressions. The plays are written in Brajavali, a mix of Assamese and Maithili.

Explanation

Option (d) is correct: Methyl alcohol (methanol) is a highly toxic substance that is sometimes illegally added to liquor to reduce costs. Once consumed, it metabolizes into formaldehyde and formic acid, causing blindness, organ failure, or death. Symptoms of methanol poisoning include blurred vision, nausea, and seizures. Options (a), (b) and (c) are incorrect:

Ethyl alcohol is commonly known as ethanol, it is the primary component in alcoholic beverages and is safe for consumption in moderate amounts. Amyl alcohol is found in some industrial applications, amyl alcohol is rarely used in adulterated liquor due to its cost and limited availability. Benzyl alcohol is a non-toxic solvent and not associated with blindness in liquor tragedies. It is used in pharmaceuticals and cosmetics.

Explanation

The physico-chemical characteristics of water in water sources are primarily affected by effluents discharged from various sources, including industries, sewage, and agricultural runoff. Effluents introduce pollutants like organic matter, chemicals, heavy metals, and nutrients into water bodies, leading to significant changes in water quality. How Effluents cause Changes:

Chemical Changes: Effluents can alter the pH, increase the concentration of harmful chemicals, and introduce toxic substances. Nutrient Loading: Excessive nutrients (like nitrates and phosphates) from effluents can cause eutrophication, leading to algal blooms. Dissolved Oxygen Levels: Organic pollutants increase the Biological Oxygen Demand (BOD), reducing dissolved oxygen levels and harming aquatic life. Turbidity and Color: Effluents can increase turbidity, reduce light penetration, and alter the color of the water.

Explanation

Hawala transactions refer to an informal and unof-ficial system of transferring money across borders without using formal banking channels or regulatory oversight. It involves a network of brokers (hawaladars) who facilitate the transfer of money between individuals or entities in different countries. For example, if Person A in Country X wants to send money to Person B in Country Y, they give the money to a hawaladar in Country X. The hawaladar then instructs their coun-terpart in Country Y to deliver the equivalent amount to Person B. No physical movement of money occurs across borders, and the transaction is based on trust and informal records. Options (b), (c) and (d) are incorrect:

Unauthorized stock transfers without using stock exchanges fall under insider trading or securities fraud and not Hawala. Received as commission for services rendered to overseas investors/buyers/sellers in assisting them to get over the red tape and/or in getting preferential treatment" refers to bribery or facilitation payments to bypass bureaucratic hurdles, which is a corruption issue. While Hawala channels can be used for illegal election funding, the term itself does not directly refer to political payments.

Explanation

The average household size refers to the average number of people living in a household. It is calculated using the following formula:

Average Household Size=Total Population/Total Number of Households. For example, if a country has a population of 100 million and 20 million households, the average household size would be: 100,000,000/20,000,000=5 persons per household. Based on the 1991 Census data, the average household sizes (number of persons per household) for the given states are as follows:

1. Uttar Pradesh: 6.2 persons per household

2. West Bengal: 5.4 persons per household

3. Gujarat: 5.5 persons per household

4. Kerala: 5.3 persons per household The average household size in India has been decreasing over the decades due to declining birth rates, urbanization, and changes in family structures. States like Uttar Pradesh and Bihar have larger household sizes due to higher fertility rates and joint families. Kerala and Tamil Nadu have smaller household sizes due to better education, family planning, and higher migration. v v v

Explanation

Living organisms require a variety of elements for various physiological functions. Among these, certain elements are required in major quantities (also known as macronutrients). The elements potassium (K), sodium (Na), magnesium (Mg), and calcium (Ca) are macronutrients required in relatively large amounts by living organisms:

Potassium (K) is vital for cell function, maintaining osmotic balance, and nerve transmission. Sodium (Na) is important for maintaining osmotic pressure and fluid balance, as well for nerve function. Magnesium (Mg) is essential for photosynthesis in plants, enzyme function, and the structural component of bones in animals. Calcium (Ca) is crucial for bone and teeth formation, muscle contraction, blood clotting, and nerve function.

Explanation

Seedless tomatoes can be produced through a process called parthenocarpy where fruits develop without fertilization and thus contain no seeds. This is achieved by spraying hormones like gibberellins or auxins on the flowers of the tomato plants. These hormones promote fruit development without the need for fertilization leading to seedless fruits.