Sound (Physics)
WEeb.in Team Science Total Views: 524 Posted: Feb 6, 2020 Updated: Oct 6, 2026
SOUND
- Sound is a longitudinal wave, in which the individual particles of the medium move in a direction parallel to the direction of propagation of the disturbance. The particles do not move from one place to another but they simply oscillate back and forth about their position of rest.
- The two important properties of sound are:
| Amplitude | Frequency |
| The maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. | Frequency is the number of occurrences of a repeating event per unit of time |
| Determines the loudness of the sound. Larger the amplitude – louder the sound | Determines the pitch of the sound – higher the frequency, higher the pitch |
- One Important note to make, the speed of sound in a gaseous medium is inversely proportional to the square root of the density of the gas.
- Speed of sound increases with the increase in temperature of the medium
- Minimum distance of the obstacle from source of sound for hearing distinct echo is 17.2 m at 22 degrees Celsius with speed of sound in air at 344 m/s
- Reverberation is the phenomenon of prolongation of sound due to successive reflection of sound from surrounding objects
- Audible Ranges of Sound:
| < 20 Hz ( Less than 20 Hz) | Infrasonic Sound | Animals like Elephants, Whales |
| 20 Hz to 20000 Hz | Audible Sound | Audible range for Huma Beings |
| > 20000 Hz ( Greater than 20000 Hz) | Ultrasonic Sound | Animals like Bats, Dolphins |
- SONAR which stands for Sound Navigation and Ranging is a device that uses ultrasonic waves to measure the distance, direction and speed of underwater.
- If the speed of the aircraft is more than the speed of sound, then the aircraft is said to have achieved supersonic speed
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