Question

The speed of ultrasonic, infrasonic and audible sound will be the same in a given medium.’
Do you agree with this statement?
Justify your answer.

Answer 1

Answer:

There are 3 types sound waves which can be classified as Audible Sound waves, Infrasonic sound waves, and Ultrasonic sound waves.

Infrasonic waves are inaudible to human ear and their frequency ranges are below 20hz.

Audible waves are heard by human ear and their frequency ranges between 20hz and 20000hz.

Ultrasonic waves are also inaudible to human ear and their frequency ranges are above 20000hz.

Sound waves are independent upon the wave characteristics such as frequency, period, and amplitude. Its speed depends on the properties of the medium through which it travels. Sound waves travels faster in solid, fast in liquid and slow in air. It cannot travel in vacuum.

Sound wave of all the frequencies in ideal gases and in air travels at the same speed. Presence of dust particles and carbon dioxide in air does affect the speed but of negligible significance. It travels at different speed through solid medium though.

Sound wave travels in air as longitudinal waves and the speed of sound in air depends on temperature only, not on the pressure or density. The speed of sound in air at 0 degree centigrade is 331.3 meters per second. The sound of speed in air is increased by 0.60 m/s for each increase of degree in air temperature. Only extreme altitudes affect the speed of the sound wave in air.

Speed of sound in air travels at 343.21 m/s at 20 degree centigrade. Speed of sound travels at 1,484 m/s in water and travels at 5,120 m/s in iron.

However in solid, sound wave travels both in longitudinal waves and transverse waves. Velocity through a given medium is inversely related to the density and directly related to stiffness of that medium. Ultra sonic sound waves travel faster through a stiff medium, such as bone.