1. Sound travels in air if

2. Sound waves in air is an example of ______

3. The phenomenon where a sound produced is heard again due to reflection is called _____

4. When a body vibrates, it compresses the air surrounding and forms a high-density area known as ______

5. Speed of sound depends upon

6. In the curve half the wavelength is

7. Infrasound can be heard by

8. A wave in slinky travelled two and fro in 5 sec the length of the slinky is 5 m. What is the velocity of wave?

9. Note is a sound

10. The number of compressions or rarefactions per unit time gives

11. Earthquake produces which kind of sound before the main shock wave begins

12. In SONAR, we use

13. When the vibrating object moves backwards, it creates a region of low pressure called ______

14. Children under the age of 5 can hear upto

15. When we change feeble sound to loud sound we increase its