Regarding the atom of a chemical element, the magnetic quantum number refers to
- (a)orientation
- (b)shape
- (c)size
- (d)spin
Show answerHide answer
Official answer(a) orientation
Science & Technology
923 questions asked in UPSC Prelims.
Assertion (A): In the periodic table of chemical elements, electron affinity is always found to increase from top to bottom in a group. Reason (R): In a group, the atomic radius generally increases from top to bottom.
- (a)Both A and R are individually true and R is the correct explanation of A
- (b)Both A and R are individually true but R is NOT the correct explanation of A
- (c)A is true but R is false
- (d)A is false but R is true
Show answerHide answer
Official answer(d) A is false but R is true
Assertion (A): Unsaturated fats are more reactive compared with the saturated fats. Reason (R): Unsaturated fats have only single bonds in their structure.
- (a)Both A and R are individually true and R is the correct explanation of A
- (b)Both A and R are individually true but R is NOT the correct explanation of A
- (c)A is true but R is false
- (d)A is false but R is true
Show answerHide answer
Official answer(c) A is true but R is false
Three bells toll at intervals of 9, 12 and 15 minutes respectively. All three begin to toll at 8 a.m. At what time will they first toll together again?
- (a)8.45 a.m.
- (b)10.30 a.m.
- (c)11.00 a.m.
- (d)1.30 p.m.
Show answerHide answer
Official answer(c) 11.00 a.m.
Among the following which planet takes maximum time for one revolution around the Sun?
- (a)Earth
- (b)Jupiter
- (c)Mars
- (d)Venus
Show answerHide answer
Official answer(b) Jupiter
With reference to normal human beings, consider the following statements: 1. In response to the presence of HCl, secretin is produced from the duodenum 2. Enterogastrone is produced in the small intestine in response to the presence of fatty acids Which of these statements is/are correct?
- (a)Only 1
- (b)Only 2
- (c)Both 1 and 2
- (d)Neither 1 nor 2
Show answerHide answer
Official answer(c) Both 1 and 2
Total time taken by a person in going to a place by walking and returning on cycle is 5 hours 45 minutes. He would have gained 2 hours by cycling both ways. The time taken by him to walk both ways is
- (a)6 hours 45 minutes
- (b)7 hours 45 minutes
- (c)8 hours 15 minutes
- (d)8 hours 30 minutes
Show answerHide answer
Official answer(b) 7 hours 45 minutes
‘A’ and ‘B’ are two fixed points in a field. A cyclist C moves such that ACB is always a right angle. In this context, which one of the following statements is correct?
- (a)The path followed by the cyclist is an ellipse
- (b)The path followed by the cyclist is a circle
- (c)The path followed by the cyclist is an exponential curve
- (d)This type of motion is not possible
Show answerHide answer
Official answer(b) The path followed by the cyclist is a circle
With reference to ionic compounds, consider the following statements: 1. Ionic compounds are insoluble in alcohol. 2. Ionic compounds in the solid state are good conductors of electricity. Which of these statements is/are correct?
- (a)Only 1
- (b)Only 2
- (c)Both 1 and 2
- (d)Neither 1 nor 2
Show answerHide answer
Official answer(a) Only 1
Which one of the following statements is correct?
- (a)The presence of NaCl increases the rate of setting of Plaster of Paris
- (b)Gypsum is added to the cement to slow down its rate of setting
- (c)All alkaline earth metals form hydrated salts
- (d)Barium and Strontium are found free in nature
Show answerHide answer
Official answer(d) Barium and Strontium are found free in nature
A complete cycle of a traffic light takes 60 seconds. During each cycle the light is green for 25 seconds, yellow for 5 seconds and red for 30 seconds. At a randomly chosen time, the probability that the light will not be green is
- (a)1/3
- (b)1/4
- (c)5/12
- (d)7/12
Show answerHide answer
Official answer(d) 7/12
A solid cube just gets completely immersed in water when a 0.2 kg mass is placed on it. If the mass is removed, the cube is 2 cm above the water level. What is the length of each side of the cube?
- (a)12 cm
- (b)10 cm
- (c)8 cm
- (d)6 cm
Show answerHide answer
Official answer(b) 10 cm
With reference to the latest developments in stem-cell research, consider the following statements: 1. The only source of human stem cells are the embryos at blastocyst stage. 2. The stem cells can be derived without causing destruction to blastocysts. 3. The stem cells can regenerate themselves in vitro virtually forever. 4. Indian research centres also created a few cell lines which can be developed into many types of tissues. Which of these statements are correct?
- (a)1, 2, 3 and 4
- (b)1, 2 and 3
- (c)1, 2 and 4
- (d)3 and 4
Show answerHide answer
Official answer(d) 3 and 4
In the year 2001, NASA launched a spacecraft to Mars named
- (a)Mars Climate Orbiter
- (b)Mars Global Surveyor
- (c)Mars Odyssey
- (d)Mars Polar Lander
Show answerHide answer
Official answer(c) Mars Odyssey
A trader fixed the price of an article in such a way that by giving a rebate of 10 % on the price fixed he made a profit of 15 %. If the cost of the article is Rs 72, the price fixed on it is
- (a)Rs 82.80
- (b)Rs 90.00
- (c)Rs 92.00
- (d)Rs 97.80
Show answerHide answer
Official answer(c) Rs 92.00
Among living organisms, which one of the following is the most responsible factor for bringing about the origin of a new species?
- (a)Isolation
- (b)Mutation
- (c)Natural Selection
- (d)Sexual Reproduction
Show answerHide answer
Official answer(a) Isolation
Consider the volumes of the following: 1. A parallelepiped of length 5 cm, breadth 3 cm and height 4 cm 2. A cube of each side 4 cm 3. A cylinder of radius 3 cm and length 3 cm 4. A sphere of radius 3 cm The volumes of these in the decreasing order is
- (a)I, III, II, IV
- (b)IV, II, III, I
- (c)I, II, III, IV
- (d)IV, III, II, I
Show answerHide answer
Official answer(d) IV, III, II, I
Ticks and mites are actually
- (a)Arachnids
- (b)Crustaceans
- (c)Insects
- (d)Myriapods
Show answerHide answer
Official answer(a) Arachnids
With reference to the blood in a normal person, which one of the following statements is correct?
- (a)Compared to arteries, veins are less numerous and hold less of the body’s blood at any given time
- (b)Blood cells constitute about 70 % of the total volume of the blood
- (c)White Blood Cells (WBC) are made by lymph nodes only
- (d)The blood has more platelets than WBC
Show answerHide answer
Official answer(d) The blood has more platelets than WBC
Which one of the following statements is correct?
- (a)The boiling point of an aqueous solution is higher than that of pure water
- (b)Addition of solutes to a solution causes an increase in its water potential
- (c)The vapour pressure of the water in a solution is lower than that of pure water
- (d)When a solution is separated from water by a semi permeable membrane, water movement can be prevented by applying pressure to the solution
Show answerHide answer
Official answer(b) Addition of solutes to a solution causes an increase in its water potential
Consider the following plants: 1. Bougainvillea 2. Carnations 3. Cocoa 4. Grapes Which of these plants are propagated by stem cuttings?
- (a)1 and 2
- (b)2, 3 and 4
- (c)1, 3 and 4
- (d)1, 2, 3 and 4
Show answerHide answer
Official answer(d) 1, 2, 3 and 4
A train of length 150 metres, moving at a speed of 90 km/hr can cross a 200-metre bridge in
- (a)8 seconds
- (b)14 seconds
- (c)6 seconds
- (d)15 seconds
Show answerHide answer
Official answer(b) 14 seconds
Consider the following natural phenomena: 1. Terrestrial heating 2. Reflection of light 3. Refraction of light 4. Diffraction of light Due to which of these phenomena is mirage formed?
- (a)1 and 2
- (b)2, 3 and 4
- (c)1 and 3
- (d)4 only
Show answerHide answer
Official answer(c) 1 and 3
In the context of the organic evolution, the loss of limbs of snakes is explained by the phenomenon of
- (a)use and disuse of organs
- (b)adaptation to living in burrows
- (c)natural selection
- (d)inheritance of acquired characters
Show answerHide answer
Official answer(a) use and disuse of organs
When one gene controls two or more different characters simultaneously, the phenomenon is called
- (a)Apomixis
- (b)Pleiotropy
- (c)Polyploidy
- (d)Polyteny
Show answerHide answer
Official answer(b) Pleiotropy