Science & Technology PYQs

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1. Prelims 2011Q18Biology & Human Body

   When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up and dies because

   aWater from soil cannot rise to aerial partsbRoots are starved of energycTree is infected by soil microbesdRoots do not receive oxygen for respiration
2. Prelims 2011Q27Physics

   A layer in the Earth’s atmosphere called Ionosphere facilitates radio communication. Why?

   1.The presence of ozone causes the reflection of radio waves to Earth.

   2.Radio waves have a very long wavelength.

   Which of the statements given above is/are correct?

   a1 onlyb2 onlycBoth 1 and 2dNeither 1 nor 2
3. Prelims 2011Q29Biotechnology

   A genetically engineered form of brinjal, known as the Bt-brinjal, has been developed. The objective of this is

   aTo make it pest-resistantbTo improve its taste and nutritive qualitiescTo make it drought-resistantdTo make its shelf-life longer
4. Prelims 2011Q32Defence & Nuclear Technology

   The function of heavy water in a nuclear reactor is to

   aSlow down the speed of neutronsbIncrease the speed of neutronscCool down the reactordStop the nuclear reaction
5. Prelims 2011Q40Health & Diseases

   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?

   a1 onlyb2 and 3 onlyc1 and 3 onlyd1, 2 and 3
6. Prelims 2011Q50Physics

   The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid.

   What is the reason ?

   aIce is a bad conductor of heatbSince the surface of the lake is at the same temperature as the air, no heat is lostcThe density of water is maximum at 4°CdNone of the statements (a), (b) and (c) given above is correct
7. Prelims 2011Q57IT & Communication

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

   aBluetooth uses 2.4 GHz radio frequency band, whereas Wi-Fi can use 2.4 GHz or 5 GHz frequency bandbBluetooth is used for Wireless Local Area Networks (WLAN) only, whereas Wi-Fi is used for Wireless Wide Area Networks (WWAN) onlycWhen 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 otherdThe statements (a) and (b) given above are correct in this context
8. Prelims 2011Q62Health & Diseases

   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?

   aAspartame is as sweet as table sugar, but unlike table sugar, it is not readily oxidized in human body due to lack of requisite enzymesbWhen aspartame is used in food processing, the sweet taste remains, but it becomes resistant to oxidationcAspartame is as sweet as sugar, but after ingestion into the body, it is converted into metabolites that yield no caloriesdAspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation
9. Prelims 2011Q64Physics

   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?

   a1 onlyb2 and 3 onlyc1 and 3 onlyd1, 2 and 3
10. Prelims 2011Q66Biology & Human Body

    A married couple adopted a male child. A few years later twin boys were born to them. The blood group of the couple is AB positive and O negative. The blood group of the three sons is A positive, B positive, and O positive. The blood group of the adopted son is

    aO positivebA positivecB positivedCannot be determined on the basis of the given data
11. Prelims 2011Q69IT & Communication

    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?

    a1 onlyb1 and 2 onlyc2 and 3 onlyd1, 2 and 3
12. Prelims 2011Q81Physics

    An artificial satellite orbiting around the Earth does not fall down. This is so because the attraction of Earth

    adoes not exist at such distancebis neutralized by the attraction of the mooncprovides the necessary speed for its steady motiondprovides the necessary acceleration for its motion
13. Prelims 2011Q86Space Technology

    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?

    a1 and 2 onlyb1 and 3 onlyc3 onlyd1, 2 and 3
14. Prelims 2011Q91Health & Diseases

    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?

    aThey activate the enzymes necessary for vitamin synthesis in the body and help prevent vitamin deficiencybThey prevent excessive oxidation of carbohydrates, fats and proteins in the body and help avoid unnecessary wastage of energycThey neutralize the free radicals produced in the body during metabolismdThey activate certain genes in the cells of the body and help delay the ageing process
15. Prelims 2011Q99IT & Communication

    What is "Virtual Private Network"?

    aIt is a private computer network of an organization where the remote users can transmit encrypted information through the server of the organization.bIt 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.cIt is a computer network in which users can access a shared pool of computing resources through a service provider.dNone of the statements (a), (b) and (c) given above is a correct description of Virtual Private Network.
16. Prelims 2010Q2Physics

    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

    aPotato is mainly made up of starch whereas paper is mainly made up of cellulosebPotato transmits microwaves whereas paper reflects microwavescPotato contains water whereas paper does not contain waterdPotato is a fresh organic material whereas paper is a dead organic material
17. Prelims 2010Q5Biotechnology

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

    aIt is a genetically modified dwarf variety which is resistant to droughtbIt is a genetically modified variety which is pest resistantcIt is a genetically modified variety with ten times higher protein content than regular maize cropdIt is a genetically modified variety used exclusively for bio-fuel production
18. Prelims 2010Q7Space Technology

    Consider the following statements:

    The satellite Oceansat-2 launched by India helps in

    1.Estimating the water vapour content in the atmosphere.

    2.Predicting the onset of monsoons.

    3.Monitoring the pollution of coastal waters.

    Which of the statements given above is/are correct?

    a1 and 2 onlyb2 onlyc1 and 3 onlyd1, 2 and 3
19. Prelims 2010Q8Biotechnology

    Genetically modified “golden rice” has been engineered to meet human nutritional requirements.

    Which one of the following statements best qualifies golden rice?

    aThe grains have been fortified with genes to provide three times higher grain yield per acre than other high yielding varietiesbIts grains contain pro-vitamin A which upon ingestion is converted to vitamin A in the human bodycIts modified genes cause the synthesis of all the nine essential amino acidsdIts modified genes cause the fortification of its grains with vitamin D
20. Prelims 2010Q11Chemistry

    Chlorination is a process used for water purification. The disinfecting action of chlorine is mainly due to

    aThe formation of hydrochloric acid when chlorine is added to waterbThe formation of hypochlorous acid when chlorine is added to watercThe formation of nascent oxygen when chlorine is added to waterdThe formation of hydrogen when chlorine is added to water