1A boy blows a whistle with a power of 2 × 10⁻⁴ W. Calculate the intensity of the sound over an area of 5 square metres.
2By listening to or recording the sounds of different animals, find out which animal's sound has smaller intensity and which has greater intensity, and give the reason.
3If you were blindfolded and placed somewhere, write how you would tell whether it is a furnished room, an empty room or an open place.
4What is the intensity of sound? Write its SI unit.
5What is the relation between the intensity of sound and the loudness of sound? In which unit is loudness measured?
6Why does the intensity of sound fall as the distance between the source and the listener increases?
7Why is the intensity of sound greater in cold air?
8Write the five factors that affect the intensity of sound.
9Explain the difference between being hard of hearing and being deaf, in terms of decibels.
10A machine gives out a sound power of 9 × 10⁻³ W. If this power falls on an area of 3 square metres, find the intensity of the sound.