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Science & Technology

923 questions asked in UPSC Prelims.

2012 · Q86Science & TechnologyMaterials & Engineeringmoderate

Recently, there has been a concern over the short supply of a group of elements called 'rare earth metals'. Why? 1. China, which is the largest producer of these elements, has imposed some restrictions on their export. 2. Other than China, Australia, Canada and Chile, these elements are not found in any country. 3. Rare earth metals are essential for the manufacture of various kinds of electronic items and there is a growing demand for these elements. Which of the statements given above is/are correct?

  1. (a)1 only
  2. (b)2 and 3 only
  3. (c)1 and 3 only
  4. (d)1, 2 and 3
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Official answer(c) 1 and 3 only

2012 · Q93Science & TechnologyPhysicsmoderate

Consider the following statements : If there were no phenomenon of capillarity 1. it would be difficult to use a kerosene lamp 2. one would not be able to use a straw to consume a soft drink 3. the blotting paper would fail to function 4. the big trees that we see around would not have grown on the Earth Which of the statements given above are correct?

  1. (a)1, 2 and 3 only
  2. (b)1, 3 and 4 only
  3. (c)2 and 4 only
  4. (d)1, 2, 3 and 4
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Official answer(b) 1, 3 and 4 only

2011 · Q3Science & TechnologySpace Technology & Astronomymoderate

Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such an orbit when: 1. The orbit is geosynchronous. 2. The orbit is circular. 3. The orbit lies in the plane of the Earth’s equator. 4. The orbit is at an altitude of 22,236 km. Select the correct answer using the codes given below:

  1. (a)1, 2 and 3 only
  2. (b)1, 3 and 4 only
  3. (c)2 and 4 only
  4. (d)1, 2, 3 and 4
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Official answer(a) 1, 2 and 3 only

2011 · Q5Science & TechnologyBiotechnology & Geneticsmoderate

At present, scientists can determine the arrangement or relative positions of genes or DNA sequences on a chromosome. How does this knowledge benefit us? 1. It is possible to know the pedigree of livestock. 2. It is possible to understand the causes of all human diseases. 3. It is possible to develop disease-resistant animal breeds. Which of the statements given above is/are correct?

  1. (a)1 and 2 only
  2. (b)2 only
  3. (c)1 and 3 only
  4. (d)1, 2 and 3
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Official answer(c) 1 and 3 only

2011 · Q7Science & TechnologyEnergy & Environmentmoderate

Microbial fuel cells are considered a source of sustainable energy. Why? 1. They use living organisms as catalysts to generate electricity from certain substrates. 2. They use a variety of inorganic materials as substrates. 3. They can be installed in waste water treatment plants to cleanse water and produce electricity. Which of the statements given above is/are correct?

  1. (a)1 only
  2. (b)2 and 3 only
  3. (c)1 and 3 only
  4. (d)1, 2 and 3
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Official answer(c) 1 and 3 only

2011 · Q40Science & TechnologyHealth & Diseasesmoderate

A company marketing food products advertises that its items do not contain trans-fats. What does this campaign signify to the customers? 1. The food products are not made out of hydrogenated oils. 2. The food products are not made out of animal fats/oils. 3. The oils used are not likely to damage the cardiovascular health of the consumers. Which of the statements given above is/are correct?

  1. (a)1 only
  2. (b)2 and 3 only
  3. (c)1 and 3 only
  4. (d)1, 2 and 3
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Official answer(c) 1 and 3 only

2011 · Q57Science & TechnologyComputer & Information Technologyeasy

What is the difference between Bluetooth and Wi-Fi devices ?

  1. (a)Bluetooth uses 2.4 GHz radio frequency band, whereas Wi-Fi can use 2.4 GHz or 5 GHz frequency band
  2. (b)Bluetooth is used for Wireless Local Area Networks (WLAN) only, whereas Wi-Fi is used for Wireless Wide Area Networks (WWAN) only
  3. (c)When information is transmitted between two devices using Bluetooth technology, the devices have to be in the line of sight of each other, but when Wi-Fi technology is used the devices need not be in the line of sight of each other
  4. (d)The statements (a) and (b) given above are correct in this context
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Official answer(a) Bluetooth uses 2.4 GHz radio frequency band, whereas Wi-Fi can use 2.4 GHz or 5 GHz frequency band

2011 · Q62Science & TechnologyHealth & Diseasesmoderate

Aspartame is an artificial sweetener sold in the market. It consists of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use?

  1. (a)Aspartame is as sweet as table sugar, but unlike table sugar, it is not readily oxidized in human body due to lack of requisite enzymes
  2. (b)When aspartame is used in food processing, the sweet taste remains, but it becomes resistant to oxidation
  3. (c)Aspartame is as sweet as sugar, but after ingestion into the body, it is converted into metabolites that yield no calories
  4. (d)Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation
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Official answer(d) Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation

2011 · Q64Science & TechnologyEnergy & Environmentmoderate

What is the difference between a CFL and an LED lamp? 1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semi-conductor material. 2. The average life span of a CFL is much longer than that of an LED lamp. 3. A CFL is less energy-efficient as compared to an LED lamp. Which of the statements given above is/are correct?

  1. (a)1 only
  2. (b)2 and 3 only
  3. (c)1 and 3 only
  4. (d)1, 2 and 3
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Official answer(c) 1 and 3 only

2011 · Q65Science & TechnologyBiotechnology & Geneticseasy

Recently, ‘oilzapper’ was in the news. What is it?

  1. (a)It is an eco-friendly technology for the remediation of oily sludge and oil spills
  2. (b)It is the latest technology developed for under sea oil exploration
  3. (c)It is a genetically engineered high biofuel yielding maize variety
  4. (d)It is the latest technology to control the accidentally caused fires in oil wells
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Official answer(a) It is an eco-friendly technology for the remediation of oily sludge and oil spills

2011 · Q69Science & TechnologyComputer & Information Technologymoderate

A new optical disc format known as the Blu-ray Disc (BD) is becoming popular. In what way is it different from the traditional DVD? 1. DVD supports Standard Definition video while BD supports High Definition video. 2. Compared to a DVD, the BD format has several times more storage capacity. 3. Thickness of BD is 2.4 mm while that of DVD is 1.2 mm. Which of the statements given above is/are correct?

  1. (a)1 only
  2. (b)1 and 2 only
  3. (c)2 and 3 only
  4. (d)1, 2 and 3
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Official answer(b) 1 and 2 only

2011 · Q86Science & TechnologySpace Technology & Astronomymoderate

What is the difference between asteroids and comets? 1. Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material. 2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and Mercury. 3. Comets show a perceptible glowing tail, while asteroids do not. Which of the statements given above is/are correct?

  1. (a)1 and 2 only
  2. (b)1 and 3 only
  3. (c)3 only
  4. (d)1, 2 and 3
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Official answer(b) 1 and 3 only

2011 · Q91Science & TechnologyHealth & Diseaseseasy

Regular intake of fresh fruits and vegetables is recommended in the diet since they are a good source of antioxidants. How do antioxidants help a person maintain health and promote longevity?

  1. (a)They activate the enzymes necessary for vitamin synthesis in the body and help prevent vitamin deficiency
  2. (b)They prevent excessive oxidation of carbohydrates, fats and proteins in the body and help avoid unnecessary wastage of energy
  3. (c)They neutralize the free radicals produced in the body during metabolism
  4. (d)They activate certain genes in the cells of the body and help delay the ageing process
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Official answer(c) They neutralize the free radicals produced in the body during metabolism

2011 · Q99Science & TechnologyComputer & Information Technologyeasy

What is "Virtual Private Network"?

  1. (a)It is a private computer network of an organization where the remote users can transmit encrypted information through the server of the organization.
  2. (b)It is a computer network across a public internet that provides users access to their organization's network while maintaining the security of the information transmitted.
  3. (c)It is a computer network in which users can access a shared pool of computing resources through a service provider.
  4. (d)None of the statements (a), (b) and (c) given above is a correct description of Virtual Private Network.
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Official answer(b) It is a computer network across a public internet that provides users access to their organization's network while maintaining the security of the information transmitted.

2010 · Q2Science & TechnologyPhysicseasy

If a potato is placed on a pure paper plate which is white and unprinted and put in a microwave oven, the potato heats up but the paper plate does not. This is because

  1. (a)Potato is mainly made up of starch whereas paper is mainly made up of cellulose
  2. (b)Potato transmits microwaves whereas paper reflects microwaves
  3. (c)Potato contains water whereas paper does not contain water
  4. (d)Potato is a fresh organic material whereas paper is a dead organic material
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Official answer(c) Potato contains water whereas paper does not contain water

2010 · Q5Science & TechnologyBiotechnology & Geneticsmoderate

Mon 863 is a variety of maize. It was in the news for the following reason

  1. (a)It is a genetically modified dwarf variety which is resistant to drought
  2. (b)It is a genetically modified variety which is pest resistant
  3. (c)It is a genetically modified variety with ten times higher protein content than regular maize crop
  4. (d)It is a genetically modified variety used exclusively for bio-fuel production
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Official answer(b) It is a genetically modified variety which is pest resistant

2010 · Q8Science & TechnologyBiotechnology & Geneticseasy

Genetically modified “golden rice” has been engineered to meet human nutritional requirements. Which one of the following statements best qualifies golden rice?

  1. (a)The grains have been fortified with genes to provide three times higher grain yield per acre than other high yielding varieties
  2. (b)Its grains contain pro-vitamin A which upon ingestion is converted to vitamin A in the human body
  3. (c)Its modified genes cause the synthesis of all the nine essential amino acids
  4. (d)Its modified genes cause the fortification of its grains with vitamin D
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Official answer(b) Its grains contain pro-vitamin A which upon ingestion is converted to vitamin A in the human body