General Science
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41. The density of milk is measured by:
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A lactometer is a hydrometer used to estimate the specific gravity/density of milk. It is commonly used as a quick indicator of milk quality.
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42. Which instrument is used for measuring humidity in air?
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A hygrometer measures humidity, the amount of water vapour in air. A psychrometer is a type of hygrometer using wet- and dry-bulb temperatures.
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43. The working principle of a washing machine is:
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The spin-drying stage of a washing machine uses centrifugation. Rapid rotation forces water outward through the perforated drum, separating it from clothes.
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44. When is World AIDS Day observed?
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World AIDS Day is observed every year on 1 December. It was first observed in 1988 and focuses on HIV/AIDS awareness, prevention, treatment and remembrance.
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45. The science of raising silkworms to obtain silk cocoons is:
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Sericulture is the rearing of silkworms for silk production. Apiculture concerns bees, floriculture flowers, and silviculture the cultivation and management of forests.
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46. The acid present in ‘vinegar’ is:
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Acetic acid (ethanoic acid), formula CH₃COOH, is the characteristic acid in vinegar.
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47. In India, National Science Day is observed on:
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28 February 1928 marks C. V. Raman’s discovery of the Raman Effect; India observes National Science Day on this date.
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48. In India, the right to property is now recognized as:
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The 44th Constitutional Amendment Act, 1978 removed the Right to Property from Fundamental Rights; it is now protected as a constitutional legal right under Article 300A.
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49. Who was the Viceroy of India at the time of Jallianwala Bagh Massacre?
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The Jallianwala Bagh massacre occurred on 13 April 1919 during the tenure of Viceroy Lord Chelmsford.
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50. Which of the following gases is most predominant in the Sun?
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The Sun is composed mainly of hydrogen and helium. Hydrogen accounts for about 73–75% of the Sun’s mass, while nuclear fusion in its core converts hydrogen into helium and releases energy.
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51. Which one of the following organs excretes water, fat and various catabolic wastes?
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The kidneys are the principal excretory organs. They filter blood and remove nitrogenous wastes, excess water and salts through urine; their structural and functional units are called nephrons.
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52. Cooking gas (L.P.G.) is a mixture of:
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LPG is mainly a mixture of the hydrocarbons propane and butane. It is stored as a liquid under pressure and vaporizes for use as a cooking fuel.
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53. The human cell contains:
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A normal human somatic cell contains 46 chromosomes, arranged in 23 pairs. Gametes such as sperm and ova contain 23 chromosomes.
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54. Which of the following parts of our diet is required for bone and teeth structure?
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Calcium is essential for the formation and maintenance of strong bones and teeth. It is also important for muscle contraction, nerve function and blood clotting.
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55. Which of the following is called the laughing gas?
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Nitrous oxide (N₂O) is commonly called laughing gas. It has been used medically as an analgesic and anaesthetic, although uncontrolled inhalation can be dangerous.
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56. Spherical form of raindrop is due to:
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Raindrops tend towards a spherical shape because of surface tension. Surface tension minimizes the surface area of a liquid for a given volume.
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57. The colour of milk of cow is yellow due to the presence of:
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Carotene, especially beta-carotene, contributes to the yellowish colour of cow’s milk and dairy fat. It is a fat-soluble pigment obtained largely through the animal’s diet.
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58. Malaria can be cured from a drug extracted from:
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Cinchona bark contains quinine and related alkaloids that were historically important in the treatment of malaria. Modern malaria treatment uses specific antimalarial medicines according to the parasite and clinical situation.
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59. Hydrogen fuel cell vehicles produce one of the following as “exhaust”:
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A hydrogen fuel cell combines hydrogen and oxygen electrochemically to produce electricity. The main products are water and heat, so H₂O is the exhaust product.
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60. At which temperature density of water is maximum?
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Water has its maximum density at about 4°C. This anomalous expansion of water is important for aquatic ecosystems because ice floats while denser water remains below.
