2016 Archives

191. Match List I with List II and select the correct answer using the code

Match List I with List II and select the correct answer using the code given below the Lists :

List I (Isotope)	List II (Application)
A. Carbon	1. Treatment of goitre
B. Cobalt	2. Calculation of age of the earth
C. Iodine	3. Treatment of cancer
D. Uranium	4. Fuel in nuclear reactors

Code :

[amp_mcq option1=”2 3 1 4″ option2=”2 1 3 4″ option3=”4 1 3 2″ option4=”4 3 1 2″ correct=”option1″]

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The correct answer is A) 2 3 1 4.

– B. Cobalt (specifically Cobalt-60) is widely used in radiotherapy for the treatment of cancer due to its emission of gamma rays. This matches with application 3.
– C. Iodine (specifically Iodine-131) is used in the diagnosis and treatment of thyroid conditions, including goitre, as the thyroid gland absorbs iodine. This matches with application 1.
– D. Uranium (specifically Uranium-235) is the primary fuel used in nuclear reactors for generating energy through nuclear fission. Uranium isotopes (like Uranium-238) are also used in radiometric dating (Uranium-Lead dating) to calculate the age of rocks and the Earth. Application 4 (Fuel in nuclear reactors) and Application 2 (Calculation of age of the earth) are both valid uses of Uranium isotopes.
– A. Carbon: Carbon-14 is used for radiocarbon dating, but this is for dating organic materials up to around 50,000 years old, not for the age of the Earth itself (which is billions of years, dated using isotopes like Uranium). Carbon (graphite) is used as a moderator in some nuclear reactors, but not as fuel. Neither application 2 nor 4 is a direct or primary application of Carbon isotopes compared to other options.

Let’s examine the pairings in option A: A-2 (Carbon for Age of Earth), B-3 (Cobalt for Cancer), C-1 (Iodine for Goitre), D-4 (Uranium for Fuel). B-3, C-1, and D-4 are correct pairings. A-2 is incorrect as Carbon-14 dating is for organic matter, not the age of the Earth.
Let’s examine the pairings in option D: A-4 (Carbon for Fuel), B-3 (Cobalt for Cancer), C-1 (Iodine for Goitre), D-2 (Uranium for Age of Earth). B-3, C-1, and D-2 are correct pairings. A-4 is incorrect as Carbon is a moderator, not fuel, in reactors.
Both option A and D contain correct pairings for B and C. Both contain a correct pairing for D (either 2 or 4, as both are valid uses). Both contain an incorrect pairing for A. Comparing the incorrect pairings for A, linking Carbon-14 dating to ‘Age of Earth’ might be considered slightly less incorrect in the context of general dating methods related to Earth’s history than linking Carbon (as moderator) to ‘Fuel’. Therefore, option A (A-2, B-3, C-1, D-4) is the most likely intended answer, despite the flaw in the A-2 pairing.

192. Which one of the following is not a colloid ?

Which one of the following is not a colloid ?

[amp_mcq option1=”Milk” option2=”Mud” option3=”Butter” option4=”Boric acid” correct=”option4″]

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UPSC CAPF – 2016

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The correct answer is Boric acid.

– Colloids are heterogeneous mixtures where the solute particles are dispersed evenly throughout the solvent as particles that are intermediate in size between those in true solutions and those in suspensions. Colloidal particles typically have a size between 1 nanometer and 1 micrometer.
– True solutions have particle sizes less than 1 nm. Suspensions have particle sizes greater than 1 micrometer, and the particles tend to settle out over time.
– Milk is an emulsion, which is a type of colloid where liquid droplets are dispersed in another liquid.
– Butter is also an emulsion, a type of colloid.
– Mud is primarily a suspension, where solid particles (soil, clay, silt) are dispersed in water. While mud can contain some clay particles of colloidal size, it is generally classified as a suspension because the larger particles settle out.
– Boric acid (H₃BO₃) is a molecular substance that dissolves in water to form a true solution. The particles in a boric acid solution are hydrated boric acid molecules, which are of molecular size, much smaller than colloidal particles.

The Tyndall effect (scattering of light) is a characteristic property of colloids, but not of true solutions. Suspensions may also scatter light, but they are unstable and settle. Boric acid solution will not show the Tyndall effect, unlike milk or muddy water (though settling occurs in mud).

193. Which one of the following statements is not correct ?

Which one of the following statements is not correct ?

[amp_mcq option1=”The rate of evaporation depends on temperature” option2=”The rate of evaporation does not depend on surface area exposed to the atmosphere but on volume of the liquid” option3=”The rate of evaporation depends on humidity of the surroundings” option4=”The rate of evaporation depends on the wind speed” correct=”option2″]

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The statement that the rate of evaporation does not depend on surface area exposed to the atmosphere but on volume of the liquid is not correct.

Evaporation is the process where liquid turns into gas below its boiling point. It occurs at the surface of the liquid. The rate of evaporation is influenced by several factors:
A) Temperature: Higher temperature increases the kinetic energy of liquid molecules, making it easier for them to escape the surface. (Correct statement)
B) Surface area exposed: A larger surface area allows more molecules to be at the surface and escape into the atmosphere per unit time, thus increasing the rate of evaporation. Volume of the liquid affects the total amount available for evaporation but not the instantaneous rate of evaporation at a given surface area. (Incorrect statement)
C) Humidity of the surroundings: Lower humidity means the air has a lower concentration of water vapor, creating a larger concentration gradient between the liquid surface and the air, leading to faster evaporation. (Correct statement)
D) Wind speed: Wind blows away the saturated air layer above the liquid surface, replacing it with drier air, which increases the rate of evaporation. (Correct statement)

Evaporation is a crucial part of the water cycle. Other factors influencing evaporation include air pressure and the presence of dissolved substances in the liquid.

194. Water at 273 K is less effective in cooling than ice at the same tempe

Water at 273 K is less effective in cooling than ice at the same temperature. It is because :

[amp_mcq option1=”water is difficult to handle” option2=”water at 273 K has less energy than ice at the same temperature” option3=”water at 273 K has more energy than ice at the same temperature” option4=”water is not a cooling agent” correct=”option3″]

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Water at 273 K (0°C) is less effective in cooling than ice at the same temperature because water at 273 K has more energy (internal energy) than ice at the same temperature.

When ice at 0°C (273 K) melts into water at 0°C, it absorbs heat from its surroundings. This absorbed heat, known as the latent heat of fusion (approximately 334 kJ/kg for water), is used to break the bonds holding the water molecules in a fixed solid structure and transition to the liquid phase, without causing a change in temperature.
Therefore, water at 0°C possesses this latent heat energy in addition to the energy contained in ice at 0°C.
When ice is used for cooling, it absorbs heat to melt, providing significant cooling due to the latent heat. The resulting water then absorbs further heat as its temperature rises. When water at 0°C is used for cooling, it only absorbs heat as its temperature rises, which provides less cooling capacity compared to the phase change process of ice.

Latent heat is the heat required to change the state of a substance at constant temperature and pressure. Specific heat capacity is the heat required to raise the temperature of a substance by one degree.

195. A change of state directly from solid to gas without changing into liq

A change of state directly from solid to gas without changing into liquid state is called :

[amp_mcq option1=”Fusion” option2=”Sublimation” option3=”Diffusion” option4=”Emulsion” correct=”option2″]

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A change of state directly from solid to gas without changing into liquid state is called sublimation.

The transition of a substance directly from the solid to the gas state, without passing through the liquid state, is known as sublimation. This process occurs when the substance absorbs enough energy to overcome the intermolecular forces holding it in a solid state, but at a pressure and temperature where the liquid phase is unstable or does not exist.
– Fusion (Melting) is the transition from solid to liquid.
– Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration.
– Emulsion is a mixture of two or more liquids that are normally immiscible.

Sublimation is an endothermic process (requires heat). The reverse process, where a gas directly changes to a solid, is called deposition or desublimation. Common examples of substances that readily sublime include dry ice (solid CO2), iodine, and naphthalene.

196. Which one of the following is the correct order of formation of geolog

Which one of the following is the correct order of formation of geological systems in India in terms of their age ? (Starting with the oldest)

[amp_mcq option1=”Dharwars – Aravallis – Vindhyans – Cuddapahs” option2=”Aravallis – Dharwars – Cuddapahs – Vindhyans” option3=”Vindhyans – Dharwars – Aravallis – Cuddapahs” option4=”Cuddapahs – Vindhyans – Dharwars – Aravallis” correct=”option2″]

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The correct order of formation of these geological systems in India, from oldest to youngest, is Aravallis – Dharwars – Cuddapahs – Vindhyans.

The geological systems listed represent a sequence from the very old Precambrian basement rocks and fold mountains to younger Proterozoic sedimentary basins:
– Aravallis: Represents some of the oldest fold mountains and includes Archaean basement rocks and Proterozoic fold belts (Delhi Supergroup). The Archaean basement is among the oldest rocks.
– Dharwars: Archaean to Early Proterozoic greenstone belts and associated gneisses, found in the Dharwar Craton. Formed after the initial crustal stabilization which included the basement components found in Aravallis.
– Cuddapahs: Lower to Middle Proterozoic sedimentary basin deposits (Purana Group), laid down unconformably over the older Archaean and Dharwar rocks.
– Vindhyans: Upper Proterozoic to Lower Paleozoic sedimentary basin deposits (Purana Group), overlying the Cuddapahs and older formations. The Vindhyans are younger than the Cuddapahs.
Thus, the relative chronological order is generally Aravallis (basement/oldest) -> Dharwars -> Cuddapahs -> Vindhyans.

This sequence is part of the stratigraphic column of the Indian subcontinent, illustrating its formation and evolution over billions of years. The Precambrian era covers a vast span of time and includes the formation of cratons and early mountain building (like Aravallis).

197. Which of the following statements relating to Dharwar geological syste

Which of the following statements relating to Dharwar geological system are correct ?

1. They belong to Archaean geological period
2. They are metamorphosed sedimentary rocks
3. They are of great economic importance for its mineral resources
4. They are found predominantly in Karnataka, Tamil Nadu, Odisha and Jharkhand

Select the correct answer using the code given below :

[amp_mcq option1=”1, 2, 3 and 4″ option2=”2, 3 and 4 only” option3=”3 and 4 only” option4=”1 and 2 only” correct=”option1″]

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All four statements relating to the Dharwar geological system are correct in the context of general geological understanding.

1. They belong to Archaean geological period: The Dharwar Supergroup represents formations predominantly from the Late Archaean to Early Proterozoic eons. Referring to them as belonging to the Archaean period is appropriate as this covers a significant part of their formation age and geological importance.
2. They are metamorphosed sedimentary rocks: Dharwar sequences include metamorphosed sedimentary and volcanic rocks, characteristic of greenstone belts found in ancient cratons. This statement is correct.
3. They are of great economic importance for its mineral resources: The Dharwar regions are rich in valuable mineral deposits, including gold (Hutti and Kolar), iron ore, manganese, copper, etc. This statement is correct.
4. They are found predominantly in Karnataka, Tamil Nadu, Odisha and Jharkhand: The core Dharwar Craton is located in Karnataka, but formations of similar age and characteristics extend into adjoining states like Tamil Nadu, Andhra Pradesh, Maharashtra, Odisha, and Jharkhand. Listing these states is accurate regarding their predominant presence.

The Dharwar Craton is one of the oldest and most stable continental blocks globally, providing insights into early Earth processes and hosting significant mineral wealth.

198. Consider the following statements relating to salt production in India

Consider the following statements relating to salt production in India :

1. India is the second largest producer of iodised salt in the world next only to China
2. Salt mining is carried out in Himachal Pradesh
3. Gujarat is the leading producer of salt in India
4. Ground water is the important source of salt in Rajasthan

Which of the statements given above are correct ?

[amp_mcq option1=”1 and 2 only” option2=”3 and 4 only” option3=”1, 2 and 3″ option4=”2, 3 and 4″ correct=”option4″]

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Statements 2, 3, and 4 are correct. Statement 1 is likely incorrect or requires specific data context not universally agreed upon, given the options provided.

1. India is the second largest producer of iodised salt in the world next only to China: While India is a significant global salt producer (typically ranked 3rd overall) and has a large iodisation program, definitively stating it is the *second largest producer of iodised salt* after China lacks widespread confirmation across various international sources, making its correctness debatable.
2. Salt mining is carried out in Himachal Pradesh: Yes, rock salt deposits are mined in the Mandi district of Himachal Pradesh (e.g., Drang and Guma mines). This statement is correct.
3. Gujarat is the leading producer of salt in India: Yes, Gujarat is the largest salt-producing state in India, contributing over 75% of the country’s total production, mainly from seawater evaporation along its coastline. This statement is correct.
4. Ground water is the important source of salt in Rajasthan: Yes, inland salt lakes like Sambhar Lake and sub-soil brine wells, which are fed by saline groundwater, are major sources of salt production in Rajasthan. This statement is correct.

Salt production in India comes from various sources: seawater, inland lakes, sub-soil brine, and rock salt deposits. Mandatory iodisation is in place for edible salt in India to address iodine deficiency.

199. Consider the following statements relating to Sea Salinity : 1. The

Consider the following statements relating to Sea Salinity :

1. The ocean salinity depends on evaporation and precipitation
2. Any change in the temperature or density influences the salinity
3. Major source of sea salinity is terrestrial discharge by rivers

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=”option4″]

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UPSC CAPF – 2016

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All three statements relating to sea salinity are correct.

1. The ocean salinity depends on evaporation and precipitation: High evaporation increases salinity by removing water. High precipitation decreases salinity by adding fresh water. This statement is correct.
2. Any change in the temperature or density influences the salinity: Temperature affects the rate of evaporation and ice formation (brine rejection), thus influencing salinity. Density is determined by temperature and salinity. Changes in density (e.g., due to temperature changes) can cause water masses to move, influencing the distribution of salinity through mixing and circulation. This statement is correct.
3. Major source of sea salinity is terrestrial discharge by rivers: Rivers carry dissolved salts and minerals from the land, derived from the weathering of rocks, into the oceans. This continuous input over geological time is the primary reason for the ocean’s saltiness. This statement is correct.

Other contributions to sea salinity include volcanic outgassing, dissolution of seafloor rocks, and hydrothermal vents, but riverine input is the most significant source of dissolved solids.

200. A vehicle with mileage 15 km per litre contains 2 L of fuel. The vehic

A vehicle with mileage 15 km per litre contains 2 L of fuel. The vehicle gets some defect as a result of which 0.5 L of fuel gets wasted per hour when the engine is on. With what minimum speed the vehicle has to move to travel 20 km with the existing amount of fuel, if it travels with a uniform speed ?

[amp_mcq option1=”100 km per hour” option2=”120 km per hour” option3=”150 km per hour” option4=”200 km per hour” correct=”option1″]

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UPSC CAPF – 2016

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The minimum speed required to complete the 20 km journey with 2 L of fuel is 15 km per hour. Among the given options, the minimum speed that is sufficient is 100 km per hour.

Let S be the speed of the vehicle in km/h. The distance to travel is 20 km.
The time taken for the journey is T = Distance / Speed = 20/S hours.
The fuel consumed for the travel based on mileage is (Distance / Mileage) = 20 km / (15 km/L) = 20/15 L = 4/3 L.
The defect causes fuel wastage at a rate of 0.5 L per hour while the engine is on.
Total fuel wasted = (Wastage rate per hour) * Time = 0.5 * T = 0.5 * (20/S) = 10/S L.
Total fuel consumed for the journey = Fuel for travel + Fuel wasted = 4/3 + 10/S.
The available fuel is 2 L. To complete the journey, the total fuel consumed must be less than or equal to the available fuel:
4/3 + 10/S <= 2 10/S <= 2 - 4/3 10/S <= (6 - 4)/3 10/S <= 2/3 To find the minimum speed S, we rearrange the inequality: S/10 >= 3/2
S >= 10 * (3/2)
S >= 15 km/hour.
The minimum speed required is 15 km/hour. All options (100, 120, 150, 200 km/hour) are greater than 15 km/hour and thus represent speeds at which the journey is possible. Among the given options, the minimum sufficient speed is 100 km per hour.

The problem illustrates how time-dependent fuel consumption (wastage) interacts with speed and distance. Higher speed reduces travel time, thereby reducing total fuel wastage, even if the rate of wastage per hour is constant.