I. FILL IN THE BLANKS
1. To and fro or back and forth motion of an object is called _______
2.In humans, the sound is produced by the ____ or the _____
3. _____ are stretched across the voice box or larynx.
4. The vocal cords in men are about _____ mm long.
5. The _____ determines the shrillness or pitch of a sound.
6. Noise becomes physically painful at ______dB.
7. _______ on the roadside and elsewhere can reduce noise pollution.
8. ______ and ______are the two important properties of sound.
9. _______ senses the vibration of sound.
10.The loudness of sound depends on its ______ .
