Physics Questions and Answers
| 153. |
Which one of the following layers of the atmosphere is responsible for the reflection of radio waves? |
| |
- A. Stratosphere
- B. Mesosphere
- C. Ionosphere
- D. Troposhere
|
| 154. |
The substance used for the softening of hard water is |
| |
- A. copper sulphate
- B. sodium carbonate
- C. sodium hydroxide
- D. sodium chloride
|
| 155. |
The energy gap of diamond is |
| |
- A. 1 ev
- B. 2 ev
- C. 7 ev
- D. 10 ev
|
| 156. |
When water freezes into ice the density |
| |
- A. increases
- B. decreases
- C. remains constant
- D. disappears
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