In a tournament 14 teams play league matches. If each team plays against every other team once only then how many matches are played?
- (a)105
- (b)91
- (c)85
- (d)78
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Official answer(b) 91
Science & Technology
923 questions asked in UPSC Prelims.
Chlorination is a process used for water purification. The disinfecting action of chlorine is mainly due to
- (a)The formation of hydrochloric acid when chlorine is added to water
- (b)The formation of hypochlorous acid when chlorine is added to water
- (c)The formation of nascent oxygen when chlorine is added to water
- (d)The formation of hydrogen when chlorine is added to water
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Official answer(b) The formation of hypochlorous acid when chlorine is added to water
Consider the following : 1. Bluetooth device 2. Cordless phone 3. Microwave oven 4. Wi-Fi device Which of the above can operate between 2.4 and 2.5 GHz range of radio-frequency band ?
- (a)1 and 2 only
- (b)3 and 4 only
- (c)1, 2 and 4 only
- (d)1, 2, 3 and 4
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Official answer(d) 1, 2, 3 and 4
Widespread resistance of malarial parasite to drugs like chloroquine has prompted attempts to develop a malarial vaccine to combat malaria. Why is it difficult to develop an effective malaria vaccine ?
- (a)Malaria is caused by several species of Plasmodium
- (b)Man does not develop immunity to malaria during natural infection
- (c)Vaccines can be developed only against bacteria
- (d)Man is only an intermediate host and not the definitive host
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Official answer(b) Man does not develop immunity to malaria during natural infection
Two trains leave New Delhi at the same time. One travels north at 60 kmph and the other travels south at 40 kmph. After how many hours will the trains be 150 km apart?
- (a)3/2
- (b)15/4
- (c)3/4
- (d)15/2
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Official answer(a) 3/2
A question paper had ten questions. Each question could only be answered as True (T) or False (F). Each candidate answered all the questions. Yet, no two candidates wrote the answers in an identical sequence. How many different sequences of answers are possible?
- (a)20
- (b)40
- (c)512
- (d)1024
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Official answer(d) 1024
Six books A, B, C, D, E and F are placed side by side. B, C and E have blue cover and the other books have red cover. Only D and F are new books and the rest are old. A, C and D are law reports and others are Gazetters. What book is a new law report with a red colour?
- (a)A
- (b)B
- (c)C
- (d)D
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Official answer(d) D
Running at a speed of 60 km per hour, a train passed through a 1.5 km long tunnel in two minutes. What is the length of the train?
- (a)250 m
- (b)500 m
- (c)1000 m
- (d)1500 m
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Official answer(b) 500 m
India-based Neutrino Observatory is included by the Planning Commission as a mega science project under the 11th Five-Year Plan. In this context, consider the following statements: 1. Neutrinos are chargeless elementary particles that travel close to the speed of light. 2. Neutrinos are created in nuclear reactions of beta decay. 3. Neutrinos have a negligible, but non-zero mass. 4. Trillions of Neutrinos pass through human body every second. Which of the statements given above are correct?
- (a)1 and 3 only
- (b)1, 2 and 3 only
- (c)2, 3 and 4
- (d)1, 2, 3 and 4
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Official answer(d) 1, 2, 3 and 4
Hydrogen fuel-cell vehicles produce one of the following as “exhaust”.
- (a)NH₃
- (b)CH₄
- (c)H₂O
- (d)H₂O₂
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Official answer(c) H₂O
Recently, LASIK (Laser Assisted In-Situ Keratomileusis) procedure is being made popular for vision correction. Which one of the following statements in this context is not correct?
- (a)LASIK procedure is used to correct refractive errors of the eye
- (b)It is a procedure that permanently changes the shapes of the cornea
- (c)It reduces a person’s dependence on glasses or contact lenses
- (d)It is a procedure that can be done on the person of any age
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Official answer(d) It is a procedure that can be done on the person of any age
Six persons M, N, O, P, Q and R are sitting in two rows, three in each. Q is not at the end of any row. P is second to the left of R. O is the neighbour of Q and is sitting diagonally opposite to P. N is the neighbour of R. On the basis of above information, who is facing N?
- (a)R
- (b)Q
- (c)P
- (d)M
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Official answer(b) Q
A person X has four notes of Rupee 1, 2, 5 and 10 denomination. The number of different sums of money she can form from them is
- (a)16
- (b)15
- (c)12
- (d)8
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Official answer(b) 15
Two numbers X and Y are respectively 20% and 28% less than a third number Z. By what percentage is the number Y less than the number X?
- (a)8%
- (b)9%
- (c)10%
- (d)12%
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Official answer(c) 10%
Which bacterial strain, developed from natural isolates by genetic manipulations, can be used for treating oil spills ?
- (a)Agrobacterium
- (b)Clostridium
- (c)Nitrosomonas
- (d)Pseudomonas
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Official answer(d) Pseudomonas
Which feature of some species of blue-green algae helps promote them as bio-fertilizers ?
- (a)They convert atmospheric methane into ammonia which the crop plants can absorb readily.
- (b)They induce the crop plants to produce the enzymes which help convert atmospheric nitrogen to nitrates.
- (c)They have the mechanism to convert atmospheric nitrogen into a form that the crop plants can absorb readily.
- (d)They induce the roots of the crop plants to absorb the soil nitrates in larger quantities.
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Official answer(c) They have the mechanism to convert atmospheric nitrogen into a form that the crop plants can absorb readily.
A person travelled a distance of 50 km in 8 hours. He covered a part of the distance on foot at the rate of 4 km per hour and a part on a bicycle at the rate of 10 km per hour. How much distance did he travel on foot ?
- (a)10 km
- (b)20 km
- (c)30 km
- (d)40 km
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Official answer(b) 20 km
How many numbers from 0 to 999 are NOT divisible by either 5 or 7?
- (a)313
- (b)341
- (c)686
- (d)786
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Official answer(c) 686
In a group of five persons A, B, C, D and E, there is a professor, a doctor and a lawyer. A and D are unmarried ladies, and do not work. Of the married couple in the group, E is the husband. B is the brother of A and is neither a doctor nor a lawyer. Who is the professor?
- (a)B
- (b)C
- (c)A
- (d)Cannot be determined with the available data
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Official answer(a) B
Half of the villagers of a certain village have their own houses. One-fifth of the villagers cultivate paddy. One-third of the villagers are literate. Four-fifth of the villagers are below twenty-five. Then, which one of the following is certainly true?
- (a)All the villagers who have their own houses are literate
- (b)Some villagers under twenty-five are literate
- (c)A quarter of the villagers who have their own houses cultivate paddy
- (d)Half of the villagers who cultivate paddy are literate
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Official answer(b) Some villagers under twenty-five are literate
Each person's performance compared with all other persons is to be done to rank them subjectively. How many comparisons are needed in total, if there are 11 persons?
- (a)66
- (b)55
- (c)54
- (d)45
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Official answer(b) 55
What is the principle by which a cooling system (Radiator) in a motor car works?
- (a)Conduction only
- (b)Convection
- (c)Radiation only
- (d)Both conduction and radiation
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Official answer(b) Convection
Which among the following do/does not belong/belongs to the GSM family of wireless technologies?
- (a)EDGE
- (b)LTE
- (c)DSL
- (d)Both EDGE and LTE
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Official answer(c) DSL
With reference to the treatment of cancerous tumours, a tool called cyberknife has been making the news. In this context, which one of the following statements is not correct?
- (a)It is a robotic image guided system
- (b)It delivers an extremely precise dose of radiation
- (c)It has the capability of achieving sub-millimetre accuracy
- (d)It can map the spread of tumour in the body
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Official answer(d) It can map the spread of tumour in the body
Three men start together to travel the same way around a circular track of 11 km. Their speeds are 4, 5.5 and 8 kmph respectively. When will they meet at the starting point for the first time?
- (a)After 11 hours
- (b)After 21 hours
- (c)After 22 hours
- (d)After 33 hours
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Official answer(c) After 22 hours