Reflection or echo of sounds
Reflection of the sound is called echo. If the sound is interrupted somewhere in the wave, it returns to the previous place again, it is a reflection of sound. The sound that is reflected, so the echo. That is to say that the recurrence of the original sound is echoed when the source of the origin from the source has been obstructed by any remote obstacle and returned to the source.
The soundness of sound in the human brain is 0.1 seconds. After listening to a word, there is a minimum gap of 0.1 seconds to listen to a word. Therefore, it takes 0.1 seconds to listen to echo. Because the velocity of the sound is 332 meters / second in the air, the distance between the source and the reflector is 16.6 meters for the echo to listen. Water depth can be measured using Echo sounding.
Sound waves and audibility
Sound waves caused by the vibrations of the object are called sound waves when the feeling of hearing is heard in our ears. All sound waves do not cause the feeling of hearing in our ears. That is, people can not hear all the words.
Normally, people hear from 20 Hz (Hertz) to 20,000 Hz frequency. It tells the limit of hearing ablity of human. The sound of this frequency is 7m to 17mm in the air at normal pressure and heat. The audacity range for the other animals is different. The upper limit of dogs is 35,000 Hz and it is 1,00,000 Hz of bats. The voice of different people is different because of the number of vibration of sound waves or frequency.
InfraSound: The sound that is less than 20 Hz sound of this frequency is 7m to 17mm of the sound wave is not heard. At the frequency noise the waves say infrasonic waves or infrasound.
Ultrasound: The sound that has a wave of up to 20,000 Hz of the wave wave is called ultra sound.