Question

The loudness is expressed in a unit *
1 point
dB
bD
Both
None of the above
9. Human ear cannot detect frequency of *
1 point
Less than 20 HZ
More than 20 HZ
Both
None of the above
10. The ultrasound equipment works at frequencies *
1 point
Higher than 20,000 HZ
Higher than 2000 HZ
Both
None of the above
11. Unpleasant sound is called *
1 point
Noise
Music
Both
None of the above
12. Plantation at rod side can reduce *
1 point​

Answer 1

Explanation:

1. dB

2. less than 20 hz

3. higher than 20,000 hz

4. noise

5. pollution

Answer 2

Answer:

Higher than 20,000 HZ is write answer