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2013 · Q88Science & TechnologyPhysicseasy

Ball bearings are used in bicycles, cars, etc., because

  1. (a)the actual area of contact between the wheel and axle is increased
  2. (b)the effective area of contact between the wheel and axle is increased
  3. (c)the effective area of contact between the wheel and axle is reduced
  4. (d)None of the above statements is correct
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Official answer(c) the effective area of contact between the wheel and axle is reduced

2015 · Q30Science & TechnologyPhysicsmoderate

In the context of modern scientific research, consider the following statements about ‘IceCube’, a particle detector located at South Pole, which was recently in the news : 1. It is the world’s largest neutrino detector, encompassing a cubic kilometre of ice. 2. It is a powerful telescope to search for dark matter. 3. It is buried deep in the ice. 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(d) 1, 2 and 3

2013 · Q95Science & TechnologyPhysicseasy

The known forces of nature can be divided into four classes, viz., gravity, electromagnetism, weak nuclear force and strong nuclear force. With reference to them, which one of the following statements is not correct?

  1. (a)Gravity is the strongest of the four
  2. (b)Electromagnetism acts only on particles with an electric charge
  3. (c)Weak nuclear force causes radioactivity
  4. (d)Strong nuclear force holds protons and neutrons inside the nucleus of an atom
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Official answer(a) Gravity is the strongest of the four