Which of the following statements about diamond are correct ? 1. It is used as a gem in jewellery because of its ability to reflect light 2. It is a good conductor of electricity 3. It is used for cutting glass, marble stones and other hard materials 4. I

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Q: 36 (NDA-I/2011)

Which of the following statements about diamond are correct ?
1. It is used as a gem in jewellery because of its ability to reflect light
2. It is a good conductor of electricity
3. It is used for cutting glass, marble stones and other hard materials
4. It is used for drilling of rocks
Select the correct answer using the code given below :

question_subject: 

Science

question_exam: 

NDA-I

stats: 

0,23,8,23,0,7,1

keywords: 

{'diamond': [0, 0, 3, 3], 'jewellery': [0, 0, 0, 1], 'good conductor': [0, 0, 2, 0], 'marble stones': [0, 0, 0, 1], 'gem': [0, 0, 0, 1], 'electricity': [0, 0, 1, 3], 'rocks': [9, 0, 3, 15], 'light': [16, 4, 34, 62], 'other hard materials': [0, 0, 0, 1]}

The correct answer is option 1: 1, 3 and 4.

Let`s examine each statement to understand why it is correct:

1. It is used as a gem in jewellery because of its ability to reflect light: This statement is true. Diamond has a high refractive index, which means it reflects and refracts light very effectively. This property gives diamond its characteristic sparkle and makes it desirable for use in jewelry.

2. It is a good conductor of electricity: This statement is incorrect. Diamond is actually an insulator and does not conduct electricity. It is made up of carbon atoms arranged in a lattice structure that does not allow the flow of electrons.

3. It is used for cutting glass, marble stones, and other hard materials: This statement is true. Diamond is the hardest known naturally occurring substance, and its hardness makes it ideal for cutting through hard materials like glass, marble, and other stones.

4. It is used for drilling rocks: This statement is also true. Diamond drill bits, which are coated with diamond dust, are used for drilling into rocks and other hard materials. The hardness of diamond allows it to easily pierce through these materials.

Therefore, the correct answer is option 1: 1, 3, and