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UPSC Science Previous Year Questions 2011

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

a) Does not exist at such distance

b) Is neutralized by the attraction of the moon

c) Provides the necessary speed for its steady motion

d) Provides the necessary acceleration for its motion



2. 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?
a) 1 and 2 only
b) 1 and 3 only
c) 3 only
d) 1, 2 and 3



3. Consider the following:
1. Photosynthesis
2. Respiration
3. Decay of organic matter
4. Volcanic action
Which of the above add carbon dioxide to the carbon cycle on Earth?
a) 1 and 4 only 
b)2 and 3 only
c) 2, 3, and 4 only
d)1, 2, 3 and 4



4. The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason?
a) Ice is a bad conductor of heat
b) Since the surface of the lake is at the same temperature as the air, no heat is lost
c) The density of water is maximum at 4ºC
d) None of the statements (a), (b), and (c) given above is correct



5. 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?
a) They activate the enzymes necessary for vitamin synthesis in the body and help prevent vitamin deficiency
b) They prevent excessive oxidation of carbohydrates, fats, and proteins in the body and help avoid unnecessary wastage of energy
c) They neutralize the free radicals produced in the body during metabolism
d) They activate certain genes in the cells of the body and help delay the aging process



6. 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
a) O positive
b) A positive
c) B positive
d) Cannot be determined on the basis of the given data



7. When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up and dies because
a) Water from soil cannot rise to aerial parts
b) Roots are starved of energy
c) Tree is infected by soil microbes
d) Roots do not receive oxygen for respiration




8. What is a “Virtual Private Network”?
a) It is a private computing network of an organization where remote users can transmit encrypted information through the server of the organization.
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.
c) It is a computer network in which users can access a shared pool of computing resources through a service provider
d) None of the statements (a), (b), and (c) given above is a correct description of Virtual Private Network.



9. 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:
(a) 1, 2, and 3 only
(b) 1, 3, and 4 only
(c) 2 and 4 only
(d) 1, 2, 3 and 4



10. At present, scientists can determine the arrangement or relative positions of genes of 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?
a) 1 and 2 only
b) 2 only
c) 1 and 3 only
d) 1, 2 and 3



11. 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 wastewater treatment plants to cleanse water and produce electricity.
Which of the statements given above is/are correct?
a) 1 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3



12. The function of heavy water in a nuclear reactor is to
a) Slow down the speed of neutrons
b) Increase the speed of neutrons
c) Cool down the reactor
d) Stop the nuclear reaction



13. 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?
a) 1 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3



14. What is the difference between a CFL and an LED lamp?
1. To produce light, a CFL uses mercury vapor 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?
a) 1 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3


15. Recently, “oil zapper” was in the news. What is it?
a) It is an eco-friendly technology for the remediation of oily sludge and oil spills
b) It is the latest technology developed for undersea oil exploration
c) It is a genetically engineered high biofuel-yielding maize variety
d) It is the latest technology to control the accidentally caused flames from oil wells.



16. 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?
a) 1 only
b) 1 and 2 only
c) 2 and 3 only
d) 1, 2 and 3



17. A layer in the Earth’s atmosphere called Ionosphere facilitates radio communication. Why?
1. The presence of ozone causes the reflection of radio waves on Earth.
2. Radio waves have a very long wavelength.
Which of the statements given above is/are correct?
a) 1 only
b) 2 only
c) Both 1 and 2
d) Neither 1 nor 2



18. A genetically engineered form of brinjal, known as the Bt-brinjal, has been developed. The objective of this is
a) To make it pest-resistant
b) To improve its taste and nutritive qualities
c) To make it drought-resistant
d) To make its shelf-life longer



19. What is the difference between Bluetooth and Wi-Fi devices?
a) Bluetooth uses a 2.4 GHz radio frequency band, whereas Wi-Fi can use 2.4 GHz or 5 GHz frequency, band
b) Bluetooth is used for Wireless Local Area Networks (WLAN) only, whereas Wi-Fi is used for Wireless Wide Area Networks (WWAN) only
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.
d) The statements (a) and (b) given above are correct in this context


Answer: 
1-D; 2-B; 3-C; 4-A; 5-C; 
6-A; 7-B; 8-B;9-A; 10-D;


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