What is the range of frequencies associated with

(a) Infrasound:
– Frequency Range: Infrasound refers to sound waves with frequencies below the lower threshold of human hearing, which is approximately 20 Hertz (Hz). Infrasound frequencies typically span from 0.001 Hz to 20 Hz. These frequencies are so low that they fall below the range of what humans can perceive audibly. Sources of infrasound include natural occurrences like earthquakes, volcanic eruptions, wind, and some human-made sources such as large machinery or explosions.

(b) Ultrasound:
– Frequency Range: Ultrasound encompasses sound waves with frequencies higher than the upper threshold of human hearing, which is approximately 20,000 Hertz (20 kHz). Ultrasound frequencies start above 20 kHz and extend into the megahertz (MHz) range. Ultrasound finds widespread use in medical imaging, industrial processes, cleaning applications, and more. In medicine, ultrasound scans utilize frequencies ranging from around 2 to 18 MHz for diagnostic purposes.

In summary:
– Infrasound refers to extremely low-frequency sound waves below the threshold of human hearing, ranging from 0.001 Hz to 20 Hz.
– Ultrasound pertains to high-frequency sound waves beyond the range of human perception, starting above 20,000 Hz and extending into the megahertz range, commonly used in various fields including medicine and industry.