SawaalBoxसवाल बॉक्स
1999 · Q127Science & TechnologyMaterials & Engineeringmoderate

Consider the following statements: I. Glass can be etched or scratched by diamond. II. Glass can be etched or scratched by hydrofluoric acid. III. Glass can be etched or scratched by aqua regia. IV. Glass can be etched or scratched by concentrated sulphuric acid. Which of these statements are correct?

  1. (a)I and IV
  2. (b)II and III
  3. (c)I and II
  4. (d)II and IV
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Official answer(c) I and II

2026 · Q69Science & TechnologyMaterials & Engineeringmoderate

Which of the following statements with regard to Black Boxes used in modern aircrafts is/are correct ? 1. They carry a beacon emitting red light pulses to facilitate underwater detection. 2. They record both the cockpit voice and flight data. 3. Their memory units are made using either stainless steel or titanium. Select the answer using the code given below :

  1. (a)1 only
  2. (b)2 and 3 only
  3. (c)1 and 2 only
  4. (d)1, 2 and 3
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Official answer(b) 2 and 3 only

2022 · Q28Science & TechnologyMaterials & Engineeringmoderate

With reference to India, consider the following statements : 1. Monazite is a source of rare earths. 2. Monazite contains thorium. 3. Monazite occurs naturally in the entire Indian coastal sands in India. 4. In India, Government bodies only can process or export monazite. Which of the statements given above are correct ?

  1. (a)1, 2 and 3 only
  2. (b)1, 2 and 4 only
  3. (c)3 and 4 only
  4. (d)1, 2, 3 and 4
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Official answer(b) 1, 2 and 4 only

2022 · Q46Science & TechnologyMaterials & Engineeringmoderate

With reference to polyethylene terephthalate, the use of which is so widespread in our daily lives, consider the following statements : 1. Its fibres can be blended with wool and cotton fibres to reinforce their properties. 2. Containers made of it can be used to store any alcoholic beverage. 3. Bottles made of it can be recycled into other products. 4. Articles made of it can be easily disposed of by incineration without causing greenhouse gas emissions. Which of the statements given above are correct ?

  1. (a)1 and 3
  2. (b)2 and 4
  3. (c)1 and 4
  4. (d)2 and 3
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Official answer(a) 1 and 3

2020 · Q41Science & TechnologyMaterials & Engineeringdifficult

With reference to carbon nanotubes, consider the following statements : 1. They can be used as carriers of drugs and antigens in the human body. 2. They can be made into artificial blood capillaries for an injured part of human body. 3. They can be used in biochemical sensors. 4. Carbon nanotubes are biodegradable. Which of the statements given above are correct ?

  1. (a)1 and 2 only
  2. (b)2, 3 and 4 only
  3. (c)1, 3 and 4 only
  4. (d)1, 2, 3 and 4
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Official answer(c) 1, 3 and 4 only