టీజీపీఎస్సీ గ్రూప్-1 ప్రిలిమ్స్ 2002

286 ప్రశ్నలు, ప్రతిదానికి అధికారిక సమాధానం మరియు వివరణ.

ఒకే ప్రశ్న పలు సంవత్సరాల్లో వస్తే, మొదటిసారి అడిగిన సంవత్సరం కింద చూపిస్తాం.

161. Q161SCHOOL BIOLOGY: life sciences as the papers actually ask them

     The following element is present in chlorophyll?

     • aCobalt
     • bIron
     • cMagnesiumసరైన సమాధానం
     • dCalcium
     ›వివరణ

     Option C is correct because magnesium is the central metallic ion coordinated within the tetrapyrrole porphyrin ring of the chlorophyll molecule, essential for absorbing light during photosynthesis. Option A: Cobalt is the central metal ion of vitamin B12 (cobalamin), not chlorophyll. Option B: Iron is present in cytochromes and hemoglobin, and acts as a cofactor in chlorophyll synthesis, but is not part of the chlorophyll molecule itself. Option D: Calcium is found in the cell wall middle lamella and plays a signaling role, not located in chlorophyll.

162. Q162SCHOOL BIOLOGY: life sciences as the papers actually ask them

     From which part of the saffron plant is saffron collected?

     • aDried flower buds
     • bStigmaసరైన సమాధానం
     • cDried sepals
     • dDried petals
     ›వివరణ

     Option B is correct because commercial saffron is harvested exclusively from the dried stigmas along with the upper styles of the purple saffron crocus flower (Crocus sativus). Option A: Dried flower buds describe cloves (Syzygium aromaticum), not saffron. Option C: Dried sepals form the calyx and are discarded during saffron processing. Option D: Dried petals lack the aromatic compounds and intense coloring agents of saffron.

163. Q163SCHOOL BIOLOGY: life sciences as the papers actually ask them

     Guard cells are present in?

     • aPhloem
     • bStomataసరైన సమాధానం
     • cSkin glands
     • dXylem tissue
     ›వివరణ

     Option B is correct because guard cells are specialized, chloroplast-containing epidermal cells that flank and regulate the aperture of the stomatal pore. Option A: Phloem consists of sieve elements, companion cells, fibres, and parenchyma, and does not contain guard cells. Option C: Skin glands are secretory structures found in animal integument, completely unrelated to plant guard cells. Option D: Xylem tissue consists of tracheids, vessels, xylem fibres, and xylem parenchyma, without any stomatal guard cells.

164. Q164SCHOOL BIOLOGY: life sciences as the papers actually ask them

     What causes the decomposition of cosmetic substances?

     • aAlgae
     • bVirus
     • cBacteriaసరైన సమాధానం
     • dAll of these
     ›వివరణ

     Option C is correct because bacteria are heterotrophic microorganisms capable of metabolizing organic ingredients, water, and emulsifiers present in cosmetic preparations, leading to spoilage and decomposition. Option A: Algae are photoautotrophic organisms requiring light to grow and do not act as decomposers of cosmetic formulations. Option B: Viruses are obligate intracellular parasites that cannot metabolize or grow on non-living organic substrates in cosmetic jars. Option D: All of these is incorrect because neither algae nor viruses act as saprophytic agents of decomposition in cosmetic products.

165. Q165SCHOOL BIOLOGY: life sciences as the papers actually ask them

     This is referred to as sea lettuce?

     • aUlvaసరైన సమాధానం
     • bPolysiphonia
     • cSargassum
     • dBatrachospermum
     ›వివరణ

     Option A is correct because Ulva is a genus of edible green algae commonly known as sea lettuce due to its thin, translucent, and leafy green appearance. Option B: Polysiphonia is a red alga, not referred to as sea lettuce. Option C: Sargassum is a brown alga commonly known as gulfweed, not sea lettuce. Option D: Batrachospermum is a freshwater red alga commonly known as frog-spawn alga.

166. Q166SCHOOL BIOLOGY: life sciences as the papers actually ask them

     Which of the following animals has the shortest gestation period?

     • a1) Goatసరైన సమాధానం
     • b2) Cow
     • c3) Buffalo
     • d4) Camel
     ›వివరణ

     Option A is correct because the gestation period of a goat is approximately 150 days, which is the shortest duration among the animals listed. Goat gestation period: approximately 148 to 152 days Cow gestation period: approximately 280 to 285 days Buffalo gestation period: approximately 305 to 315 days Camel gestation period: approximately 390 to 410 days Option B: Cows have a gestation period of roughly 283 days, nearly twice that of goats. Option C: Buffaloes have an average gestation period of 310 days, longer than cows and goats. Option D: Camels have a gestation period of around 13 months, the longest in this group.

167. Q167SCHOOL BIOLOGY: life sciences as the papers actually ask them

     The Pangolin found in India eats this?

     • aFrogs and Toads
     • bFruits
     • cGrass
     • dAnts and Termitesసరైన సమాధానం
     ›వివరణ

     Option D is correct because the Indian Pangolin is an exclusively myrmecophagous mammal that uses its sharp claws to excavate mounds and its long, sticky tongue to feed on ants and termites. Option A: Frogs and Toads is incorrect because pangolins lack teeth and the digestive anatomy needed to capture and consume amphibians. Option B: Fruits is incorrect because pangolins are strict insectivores that do not consume plant matter. Option C: Grass is incorrect because pangolins are non-herbivorous mammals incapable of grazing or digesting cellulose.

168. Q168SCHOOL BIOLOGY: life sciences as the papers actually ask them

     The fastest running animal on land?

     • aCheetahసరైన సమాధానం
     • bDeer
     • cHorse
     • dTiger
     ›వివరణ

     Option A is correct because the cheetah is the fastest land animal on Earth, capable of reaching sprint speeds between 100 and 120 km/h in short bursts. Option B: Deer can run at speeds between 60 and 80 km/h, which is significantly slower than a cheetah. Option C: Horses reach top galloping speeds of around 70 to 88 km/h, well below the cheetah. Option D: Tigers can achieve sprint speeds of roughly 50 to 65 km/h, far slower than the cheetah.

169. Q169SCHOOL BIOLOGY: life sciences as the papers actually ask them

     When this is supplied, the tadpole rapidly undergoes metamorphosis and turns into a fully grown frog?

     • aF.S.H.
     • bL.H.
     • cThyroxineసరైన సమాధానం
     • dAdrenaline
     ›వివరణ

     Option C is correct because thyroxine, secreted by the thyroid gland, is the primary endocrine driver that triggers and regulates amphibian metamorphosis, transforming the aquatic tadpole into a terrestrial adult frog. Option A: Follicle-stimulating hormone is an anterior pituitary gonadotropin regulating gametogenesis, playing no direct role in metamorphic tissue remodeling. Option B: Luteinizing hormone controls sex steroid secretion and ovulation rather than larval metamorphosis. Option D: Adrenaline is an adrenal catecholamine mediating immediate autonomic stress responses, not systemic morphological development.

170. Q170HUMAN BODY, NUTRITION AND DISEASE

     Among the following given, which one is not a function of the liver?

     • aProduction of insulinసరైన సమాధానం
     • bBreakdown of red blood cells
     • cGlycogen synthesis
     • dProduction of bile
     ›వివరణ

     Option A is correct because insulin is an endocrine hormone synthesized and released by the beta cells of the islets of Langerhans in the pancreas, not by the liver. Option B: Breakdown of aged red blood cells is actively carried out by hepatic Kupffer cells alongside the spleen. Option C: Glycogen synthesis is a major metabolic process performed by hepatocytes to store surplus blood glucose. Option D: Production of bile salts and bile pigments is an essential digestive activity executed by the liver.

171. Q171HUMAN BODY, NUTRITION AND DISEASE

     The human heart is?

     • aNeurogenic
     • bMyogenicసరైన సమాధానం
     • cBoth neurogenic and myogenic
     • dNone of these
     ›వివరణ

     Option B is correct because the human heart is myogenic, meaning its rhythmic contractions are initiated endogenously by specialized cardiac muscle tissue in the sinoatrial node, independent of external nerve stimulation. Option A: A neurogenic heart relies on rhythmic nerve impulses dispatched from the nervous system to beat, which occurs in certain invertebrates. Option C: Pacemaking initiation is either strictly myogenic or neurogenic; the human heartbeat's intrinsic origin is purely myogenic, with nervous input serving solely to modulate rate. Option D: The human heart possesses an intrinsically myogenic pacemaking mechanism.

172. Q172HUMAN BODY, NUTRITION AND DISEASE

     The pancreas is a?

     • aEndocrine gland
     • bExocrine gland
     • cBoth endocrine gland and exocrine glandసరైన సమాధానం
     • dNone of these
     ›వివరణ

     Option C is correct because the pancreas functions as a heterocrine or mixed gland containing both exocrine and endocrine tissues. Its exocrine acinar cells secrete digestive enzymes into ducts, while its endocrine islets of Langerhans secrete hormones directly into the bloodstream. Option A: It is incomplete because the pancreas also possesses an exocrine component that produces pancreatic juice. Option B: It is incomplete because the pancreas also possesses an endocrine component that produces hormones. Option D: It is incorrect because the pancreas distinctly exhibits both endocrine and exocrine functions.

173. Q173HUMAN BODY, NUTRITION AND DISEASE

     What taste do carbohydrates have?

     • aSweetnessసరైన సమాధానం
     • bBitter taste
     • cPungent taste
     • dSourness
     ›వివరణ

     Option A is correct because simple carbohydrates such as monosaccharides and disaccharides possess a naturally sweet taste due to their interaction with sweetness receptors on the tongue. Option B: Bitter taste is elicited primarily by plant alkaloids and certain nitrogenous compounds, not carbohydrates. Option C: Pungent taste is produced by chemical irritants such as capsaicin and allyl isothiocyanate, not carbohydrates. Option D: Sourness is caused by the presence of free hydrogen ions found in acidic substances, not carbohydrates.

174. Q174HUMAN BODY, NUTRITION AND DISEASE

     How is Thiamine known to the general public?

     • aVitamin 'B' Oneసరైన సమాధానం
     • bProtein
     • cVinegar
     • dYeast
     ›వివరణ

     Option A is correct because thiamine is the systematic biochemical name for Vitamin B1, a vital water-soluble micronutrient required for glucose metabolism and nerve function. Option B: A protein is a macromolecule composed of amino acid chains, whereas thiamine is a specific organic micronutrient. Option C: Vinegar is an aqueous solution of acetic acid produced by fermentation, not a vitamin. Option D: Yeast is a biological organism that serves as a rich dietary source of thiamine, but it is not the compound itself.

175. Q175HUMAN BODY, NUTRITION AND DISEASE

     The protein called Casein is found in?

     • aBlood
     • bProtoplasm
     • cUrine
     • dMilkసరైన సమాధానం
     ›వివరణ

     Option D is correct because casein is the primary family of phosphoproteins found in mammalian milk, constituting around 80% of the total protein content in cow milk. Option A: Blood contains plasma proteins such as albumin, globulins, and fibrinogen, not casein. Option B: Protoplasm contains various structural proteins and metabolic enzymes, but does not contain the specialized nutritional protein casein. Option C: Urine does not normally contain casein; presence of protein in urine is a sign of renal filtration dysfunction.

176. Q176HUMAN BODY, NUTRITION AND DISEASE

     Among the following given, one is a water-soluble vitamin?

     • aVitamin D2
     • bVitamin D3
     • cVitamin - A
     • dAscorbic acidసరైన సమాధానం
     ›వివరణ

     Option D is correct because ascorbic acid, also known as Vitamin C, dissolves readily in water and is excreted through urine rather than being stored in adipose tissues. Water-soluble vitamins: B complex and C Fat-soluble vitamins: A, D, E, and K Option A: Vitamin D2 is a fat-soluble secosteroid stored in body fat. Option B: Vitamin D3 is fat-soluble and stored predominantly in the liver and adipose tissue. Option C: Vitamin A is a fat-soluble vitamin stored in the liver.

177. Q177HUMAN BODY, NUTRITION AND DISEASE

     Hepatitis is a disease related to

     • aHeart inflammation
     • bLiver inflammationసరైన సమాధానం
     • cKidney damage
     • dDeath of blood cells
     ›వివరణ

     Option B is correct because the term hepatitis derives from the Greek word hepar, meaning liver, combined with the suffix -itis, designating an inflammatory condition of the liver tissue. Option A: Heart inflammation is clinically referred to as carditis, myocarditis, or pericarditis. Option C: Kidney damage or inflammation is designated as nephritis or nephropathy. Option D: Death or premature destruction of red blood cells is termed hemolysis, leading to hemolytic anemia.

178. Q178HUMAN BODY, NUTRITION AND DISEASE

     Which of the following is not obtained from opium?

     • aMorphine
     • bHeroin
     • cCodeine
     • dCocaineసరైన సమాధానం
     ›వివరణ

     Option D is correct because cocaine is a tropane alkaloid extracted from the leaves of the South American coca plant (Erythroxylum coca), not from the opium poppy. Option A: Morphine is the principal natural alkaloid directly extracted from the dried latex of the opium poppy (Papaver somniferum). Option B: Heroin is a semi-synthetic opioid synthesized directly by the diacetylation of opium-derived morphine. Option C: Codeine is a naturally occurring alkaloid obtained directly from opium or synthesized from morphine for medicinal use.

179. Q179HUMAN BODY, NUTRITION AND DISEASE

     CT in CT scan stands for

     • aComputerized Transmission
     • bComputerized Tomographసరైన సమాధానం
     • cCharged Spy Design
     • dCardiac Tracer
     ›వివరణ

     Option B is correct because CT stands for Computerized Tomography or Computerized Tomograph, which combines multiple X-ray measurements taken from different angles to produce cross-sectional images of the body. Option A: Transmission refers to the passage of radiation through matter, not the standard naming convention for this radiological imaging technique. Option C: Charged Spy Design is an entirely fictitious term with no relationship to medical imaging physics. Option D: Cardiac Tracer refers to radiopharmaceuticals used in nuclear medicine imaging, not the acronym CT.

180. Q180HUMAN BODY, NUTRITION AND DISEASE

     How are medicines that are sold only on the recommendation of recognized medical professionals classified?

     • aRₓ medicinesసరైన సమాధానం
     • bSchedule - H medicines
     • cPoison
     • dLife-saving drugs

     అధికారిక సమాధానం చూపించాం. వివరణ సమీక్షలో ఉంది.

181. Q181SCHOOL CHEMISTRY

     In a simple cubic lattice, atoms are arranged at each corner. Then, the number of atoms in a unit cell is?

     • a1సరైన సమాధానం
     • b2
     • c4
     • d8
     ›వివరణ

     Option A is correct because a simple cubic lattice contains one atom at each of its eight corners, and each corner atom is shared among eight neighbouring unit cells. Number of corners in a cubic unit cell: 8 Contribution of each corner atom: 1/8 Total atoms per unit cell: 8 multiplied by 1/8 equals 1 Option B: A value of 2 corresponds to the number of net atoms in a body-centred cubic lattice. Option C: A value of 4 corresponds to the number of net atoms in a face-centred cubic lattice. Option D: The number 8 is the total count of corner lattice points, ignoring that each corner is shared across eight adjacent unit cells.

182. Q182SCHOOL CHEMISTRY

     Generally, if an atom of an electronegative element becomes an ion?

     • aIt loses one or more electrons
     • bIt gets ionized
     • cIts atomic number increases
     • dIts electron number increasesసరైన సమాధానం
     ›వివరణ

     Option D is correct because an electronegative element has a tendency to gain electrons to complete its valence shell, so when it forms an anion, its total electron count increases. Option A: Losing electrons is characteristic of electropositive elements forming cations, not electronegative elements. Option B: Getting ionized is a broad category that applies to both cation and anion formation, but it fails to describe the specific particulate change that occurs. Option C: The atomic number represents the fixed count of nuclear protons, which remains unaltered during ion formation.

183. Q183SCHOOL CHEMISTRY

     Example of molecular formation?

     • aDiamond
     • bIceసరైన సమాధానం
     • cSodium Chloride
     • dGold
     ›వివరణ

     Option B is correct because ice is a molecular solid composed of distinct H2O molecules held together by intermolecular hydrogen bonds. Option A: Diamond is a giant covalent network solid composed entirely of carbon atoms linked by strong covalent bonds, not discrete molecules. Option C: Sodium Chloride is an ionic solid formed by an extended lattice of alternating positive sodium and negative chloride ions. Option D: Gold is a metallic solid held together by metallic bonding involving fixed metal cations and a sea of delocalized electrons.

184. Q184SCHOOL CHEMISTRY

     Among the halogen acids given below, which is the strongest reducing agent?

     • aHIసరైన సమాధానం
     • bHCl
     • cHF
     • dHBr
     ›వివరణ

     Option A is correct because the hydrogen-iodine bond is the longest and weakest among the halogen acids, allowing HI to dissociate and donate electrons or hydrogen atoms most readily. Option B: HCl possesses a significantly higher bond dissociation energy than HI, making it much less effective as a reducing agent. Option C: HF has the strongest bond among the hydrogen halides and is the weakest reducing agent in the group. Option D: HBr has a stronger covalent bond than HI, making it a less potent electron donor than HI.

185. Q185SCHOOL CHEMISTRY

     What weight of H₂O₂ would give 5.6 litres of O₂ at NTP upon decomposition?

     • a17 gm.సరైన సమాధానం
     • b8.5 gm.
     • c34 gm.
     • d56 gm.
     ›వివరణ

     Option A is correct because the stoichiometric decomposition of hydrogen peroxide yields half a mole of oxygen gas for every mole of hydrogen peroxide reacted. Decomposition reaction: 2H₂O₂ → 2H₂O + O₂ Molar mass of H₂O₂ = 2(1) + 2(16) = 34 g/mol Mass of 2 moles of H₂O₂ = 68 g Volume of 1 mole of O₂ at NTP = 22.4 L 22.4 L of O₂ is produced by 68 g of H₂O₂ 5.6 L of O₂ requires (68 / 22.4) × 5.6 = 17 g of H₂O₂ Option B: 8.5 gm corresponds to the production of only 2.8 L of O₂ at NTP. Option C: 34 gm of H₂O₂ would produce 11.2 L of O₂ at NTP. Option D: 56 gm is an incorrect value arising from miscalculating the molar volume ratio.

186. Q186SCHOOL CHEMISTRY

     In a bowl, in what ascending order are oil, gas, and water arranged (from bottom to top)?

     • aWater, oil, gasసరైన సమాధానం
     • bOil, gas, water
     • cGas, oil, water
     • dWater, gas, oil
     ›వివరణ

     Option A is correct because immiscible substances arrange themselves from bottom to top in order of decreasing density, placing the densest liquid at the bottom and the least dense phase at the top. Density of water is roughly 1.0 g per cubic centimetre Density of oil is roughly 0.8 to 0.9 g per cubic centimetre Density of gas is far lower than both liquids Option B: Oil has a lower density than water and cannot sit beneath it at the bottom. Option C: Gas has the lowest density of all three and rises above the liquids rather than resting at the bottom. Option D: Gas cannot be trapped below oil in an open bowl because its lower density causes it to escape to the very top.

187. Q187SCHOOL CHEMISTRY

     Liquid helium exists at approximately the following temperature?

     • a-269°Cసరైన సమాధానం
     • b-77°C
     • c-196°C
     • d-40°C
     ›వివరణ

     Option A is correct because helium liquefies at 4.2 Kelvin under atmospheric pressure, which corresponds to approximately -269°C. Boiling point of liquid helium: 4.2 K Conversion to Celsius: 4.2 - 273.15 = -268.95°C, rounded to -269°C Option B: -77°C is close to the freezing point of ammonia (-77.7°C), far above the condensation temperature of helium. Option C: -196°C corresponds to the boiling point of liquid nitrogen, not liquid helium. Option D: -40°C is the freezing point of mercury and the temperature where Celsius and Fahrenheit scales intersect, not the state of liquid helium.

188. Q188SCHOOL CHEMISTRY

     Which of the following substances changes from solid state to gaseous state?

     • aNaCl
     • bPb(NO₃)₂
     • cNH₄Clసరైన సమాధానం
     • d(NH₄)₂Cr₂O₇
     ›వివరణ

     Option C is correct because ammonium chloride (NH4Cl) undergoes sublimation, transforming directly from a solid state to a gaseous state upon heating without passing through a liquid phase. Option A: NaCl is an ionic solid with a very high melting point that melts into a liquid rather than subliming. Option B: Pb(NO3)2 decomposes upon heating into lead(II) oxide, nitrogen dioxide, and oxygen, rather than undergoing sublimation. Option D: (NH4)2Cr2O7 undergoes exothermic chemical decomposition to form chromium(III) oxide, nitrogen gas, and water vapor, rather than a physical transition to a gas.

189. Q189SCHOOL CHEMISTRY

     What is milk?

     • aBlood dispersed with fat
     • bWater dispersed with fat
     • cFat dispersed with waterసరైన సమాధానం
     • dOil dispersed with water
     ›వివరణ

     Option C is correct because milk is an emulsion where microscopic liquid fat globules are suspended and dispersed throughout an aqueous medium containing water, proteins, and dissolved sugars. Option A: Blood is an entirely separate biological fluid consisting of cellular elements dispersed in plasma. Option B: Water dispersed in fat describes a water-in-oil emulsion such as butter, which is the exact reverse of milk. Option D: Oil dispersed with water is a generic descriptive phrase for emulsions, but milk specifically consists of milk fat dispersed in water.

190. Q190SCHOOL CHEMISTRY

     Which of the following among these is not a fire?

     • aFiber fires
     • bOil fires
     • cFires caused by lightning strikeసరైన సమాధానం
     • dFires from burning clothes
     ›వివరణ

     Option C is correct because a lightning strike is an ignition source or natural event rather than a standard recognized category or fuel-based class of fire. Option A: Fiber fires represent a recognized fuel classification of ordinary combustible materials belonging to Class A fires. Option B: Oil fires are an established class of fires involving flammable liquids, categorized under Class B fires. Option D: Fires from burning clothes represent Class A fires involving solid combustible fabrics.

191. Q191SCHOOL CHEMISTRY

     The major component in honey is

     • aMaltose
     • bFructoseసరైన సమాధానం
     • cGlucose
     • dSucrose
     ›వివరణ

     Option B is correct because fructose is the single largest chemical constituent among all sugars present in natural honey. Fructose: approximately 38 percent Glucose: approximately 31 percent Water: approximately 17 percent Other sugars: approximately 9 percent Option A: Maltose is present in honey only in small amounts, typically around 7 percent. Option C: Glucose is the second most abundant component at roughly 31 percent, less than fructose. Option D: Sucrose is present in only trace amounts, rarely exceeding 2 percent.

192. Q192SCHOOL CHEMISTRY

     What is the important raw material used to make paper?

     • aJute
     • bBambooసరైన సమాధానం
     • cCotton
     • dTurpentine
     ›వివరణ

     Option B is correct because bamboo provides long, strong cellulosic fibers and serves as one of the most prominent plant raw materials for chemical pulping in Indian paper manufacturing. Option A: Jute is predominantly used for making gunny bags, twines, and coarse textiles rather than general printing paper. Option C: Cotton linters are used only for premium specialty currency and bond papers, not as the primary bulk paper-making raw material. Option D: Turpentine is a volatile resin byproduct derived from pine trees used as a solvent and varnish base, not as a paper fiber.

193. Q193SCHOOL CHEMISTRY

     Good quality coal should predominantly possess the following characteristic?

     • aMoisture content
     • bAsh content
     • cVolatility
     • dFixed carbonసరైన సమాధానం
     ›వివరణ

     Option D is correct because fixed carbon represents the solid combustible residue remaining after volatile matter is driven off, and higher fixed carbon directly corresponds to higher heating value and superior coal grade. Option A: High moisture content reduces combustion efficiency by consuming heat for water vaporization. Option B: High ash content is an undesirable characteristic that leaves non-combustible waste and decreases thermal efficiency. Option C: High volatility leads to rapid burning with lower energy density and generates excessive smoke rather than sustained heat.

194. Q194SCHOOL CHEMISTRY

     Cement hardens due to?

     • aDehydration
     • bHydrolysis
     • cHydration and hydrolysisసరైన సమాధానం
     • dPolymerisation
     ›వివరణ

     Option C is correct because the setting and hardening of cement are exothermic processes involving the chemical hydration and hydrolysis of calcium silicates and aluminates, forming interlocking crystalline gels. Option A: Dehydration involves water loss, whereas cement requires water to set and will not cure properly in dry conditions. Option B: Hydrolysis represents only one aspect of the chemical transformation, omitting the equally vital formation of hydration products. Option D: Polymerisation involves repeating molecular units linking into long chains, which is not the inorganic mechanism of cement hydration.

195. Q195SCHOOL CHEMISTRY

     What is the percentage of gold in 14 carat gold?

     • a58 percentసరైన సమాధానం
     • b14 percent
     • c86 percent
     • d42 percent
     ›వివరణ

     Option A is correct because pure gold is designated as 24 carats, meaning 14 carat gold contains 14 parts gold out of 24 total parts by mass. Pure gold = 24 carats Fraction of gold = 14 / 24 Percentage = (14 / 24) x 100 = 58.33 percent Option B: 14 percent confuses the carat rating itself with the percentage value. Option C: 86 percent would correspond to approximately 20.6 carat gold. Option D: 42 percent represents the proportion of alloy metals mixed with the gold rather than the gold content itself.

196. Q196SCHOOL CHEMISTRY

     Which of the following is also called 'artificial silk'?

     • aPolymers
     • bRayonసరైన సమాధానం
     • cGlass wool
     • dArlotripy
     ›వివరణ

     Option B is correct because rayon is a semi-synthetic fiber manufactured by chemically regenerating natural cellulose, developed as an affordable alternative with the texture and luster of natural silk. Option A: Polymers is an overarching chemical category covering both natural and synthetic macromolecules, not a specific fiber called artificial silk. Option C: Glass wool is an insulating material made from glass fibers and is entirely unrelated to textiles. Option D: Arlotripy is a meaningless distractor with no relevance to textile science or fiber chemistry.

197. Q197SCHOOL CHEMISTRY

     The symbol for Freon is?

     • aC₂F₂
     • bCCl₂F₂సరైన సమాధానం
     • cC₂F₄
     • d(C₂F₂)n
     ›వివరణ

     Option B is correct because Freon is the commercial trade name for chlorofluorocarbons, historically and most commonly referring to Freon-12, which is dichlorodifluoromethane with the molecular formula CCl₂F₂. Option A: C₂F₂ represents difluoroacetylene, an alkyne derivative not designated as Freon. Option C: C₂F₄ represents tetrafluoroethylene, which is the monomer used to produce Teflon. Option D: (C₂F₂)n represents a hypothetical polymer of difluoroacetylene, not a refrigerant gas.

198. Q198SCHOOL PHYSICS

     Which of the forces given below has the most strength?

     • aAtomic force
     • bGravitational force
     • cElectromagnetic force
     • dNuclear forceసరైన సమాధానం
     ›వివరణ

     Option D is correct because the strong nuclear force is the most powerful fundamental force of nature, being approximately 137 times stronger than the electromagnetic force and 10 to the power of 38 times stronger than gravity. Strong nuclear force: relative strength 1 Electromagnetic force: relative strength 10^-2 Weak nuclear force: relative strength 10^-6 Gravitational force: relative strength 10^-38 Option A: Atomic force refers to interatomic or chemical interactions mediated by electromagnetism, which is far weaker than the nuclear force. Option B: Gravitational force is the weakest of all fundamental forces across subatomic scales. Option C: Electromagnetic force is significantly weaker than the strong nuclear force, operating at roughly one percent of its strength.

199. Q199SCHOOL PHYSICS

     Velocity and acceleration on a projectile path are?

     • aBoth are parallel
     • bAre anti-parallel
     • cInclined at 45° to each other
     • dAre perpendicular to each otherసరైన సమాధానం
     ›వివరణ

     Option D is correct because at the highest point of a parabolic trajectory, the vertical component of velocity becomes zero while the acceleration due to gravity acts vertically downward, making the velocity and acceleration vectors perpendicular. Option A: Velocity and acceleration are parallel only in purely linear motion along the direction of gravity, such as a freely falling body dropped from rest. Option B: Velocity and acceleration are anti-parallel only when an object is projected straight upward, not along a two-dimensional curved path. Option C: The angle between velocity and acceleration changes continuously throughout the trajectory and is not fixed at 45 degrees.

200. Q200SCHOOL PHYSICS

     Which of the equations indicated below represents simple harmonic motion? Here k is a constant, and x denotes the displacement of the object from the equilibrium position at time t.

     • ad²x/dt² + kx² = 0
     • bd²x/dt² + k/x = 0
     • cd²x/dt² + kx = 0సరైన సమాధానం
     • dd²x/dt² - kx = 0
     ›వివరణ

     Option C is correct because the defining condition of simple harmonic motion is that acceleration is directly proportional to displacement and directed toward the equilibrium position, which is represented by d²x/dt² + kx = 0. Restoring force: F = -C x Newton's second law: F = m(d²x/dt²) Equation of motion: d²x/dt² + kx = 0 where k = C/m Option A: It is incorrect because acceleration is proportional to the square of displacement rather than linear displacement. Option B: It is incorrect because acceleration is inversely proportional to displacement. Option D: It is incorrect because the negative sign leads to exponential divergence away from equilibrium rather than oscillatory motion.