Question

6. How do trees and shrubs lessen noise pollution:

7. What does a percussion instrument use to make the sounds of rhythm?

8. How can we make sure that the sound in a large movie hall does not echo?

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Answer 1

Answer:

6. Trees act as noise barriers and reduce pollution through a phenomenon called sound attenuation, which is the damping of sound.

7.Percussion instruments make sound from being struck. Often the instruments will have a hollow body, which will amplify the sound.

8.No, we can not hear a echo of sound in a cinema hall because in the cinema hall the wall are made up with few sound absorbing materials which absorb the extra sound and only once the sound is heard without echo.