| 51. | Artificial diamond is known as – |
A. silicon tetrachloride | |
B. sodium silicate | |
C. silicon hydride | |
D. silicon carbide |
| 52. | What is quartz made of? |
A. from calcium sulfate | |
B. from calcium silicate | |
C. sodium sulfate | |
D. from sodium silicate |
| 53. | What is glass? |
A. supercooled liquid | |
B. crystalline solid | |
C. liquid crystal | |
D. none of these |
| 54. | What is the main component used in manufacturing different types of glass? |
A. silica | |
B. sodium borate | |
C. calcium silicate | |
D. sodium silicate |
| 55. | A small pouch filled with silica gel is often found in pill or powder medicine bottles, because silica gel – |
A. destroys bacteria | |
B. kills germs | |
C. absorbs all the gases present in the bottle | |
D. absorbs moisture |
| 56. | Which is the most abundant gas in the atmosphere on the basis of percentage? |
A. nitrogen | |
B. carbon dioxide | |
C. hydrogen | |
D. oxygen |
| 57. | Nitrogen gas is |
A. heavier than air | |
B. lighter than air | |
C. equal to air | |
D. all are false |
| 58. | On taking a burning wick in a jar filled with nitrogen, it – |
A. burns brighter | |
B. remains unchanged | |
C. blows out | |
D. slows down |
| 59. | The semen of bulls for artificial insemination is kept in – |
A. in liquid ammonia | |
B. in liquid oxygen | |
C. in liquid nitrogen | |
D. in liquid hydrogen |
| 60. | the main constituent of air is |
A. nitrogen | |
B. Carbon dioxide | |
C. oxygen | |
D. hydrogen |