Tuesday 15 September 2015

What is the difference between supersonic, ultrasonic, and infrasonic waves?

Though all three of these end with suffix 'sonic', but only infra sonic and ultra sonic are related to the frequency of the sound, 

1. Infrasonic: is sound wave with less than 20 hertz and is too low pitched for human ear to hear.

2. Ultrasonic: is sound wave with more than 20000 hertz and is too high pitched for human ear to hear. And Ultrasonic is a word to describe sounds that is at ultrasound. So, ultrasound is noun and ultrasonic is adjective.


Image Credit: www.dreamstime.com
Now the other sonic, Supersonic is not related to frequency, rather is level of velocity of sound. Sound travels approximately at 330m/s. at STP. If any object travels at more than the speed of sound then we say that object is travelling at supersonic.

Supersonic jets are said to travel at speed greater than sound and can produce shock waves. Not really a eco-friendly thing. For example, Concorde is such plane which is suspended now due its noise and shock waves.

thank you.