| The speed of sound is |
343 m/s |
| The audible range of sound in human beings is |
20 Hz to 20,000 Hz |
| The level of sound prolonged exposure beyond which may cause permanent hearing loss |
85 dB |
| A woman’s voice is shriller than a man’s voice because of higher |
Pitch |
| The animals which produce sounds of high pitch and frequency to communicate and locate each other |
Dolphins and elephants |
| The loudness of sound is measured in |
Decibels |
| Stringed instruments have boxes attached to increase the |
Loudness of the sound produced |
| The minimum distance which is required to hear an echo |
17 metres |
| The system of sound reflection used to find the depth of oceans |
SONAR (Sound navigation ranging) |
| The phenomenon which makes the sound of an approaching train shriller |
Doppler effect |
| Sounds cannot travel in vacuum |
| Sounds travel faster in metals than in air |
| Sonic boom occurs when a super sonic aircraft crosses the sound barrier |