What term describes frequency less than 20 Hz?

What term describes frequency less than 20 Hz?

• A. Infrasonic
• B. Audible Sound
• C. Ultrasonic
• D. Hypersonic

Answer: (A)

Frequencies below what humans can hear fall into the infrasonic range. Humans typically hear roughly 20 Hz to 20 kHz, so anything below 20 Hz is infrasonic. This term specifically describes subaudible waves, like some seismic signals or certain animal communications. Audible sound covers the 20 Hz to 20 kHz range, ultrasonic refers to frequencies above 20 kHz, and hypersonic is a term used for very high-frequency sounds beyond ultrasound in some contexts. So, for frequency less than 20 Hz, infrasonic is the right label.

Frequencies below what humans can hear fall into the infrasonic range. Humans typically hear roughly 20 Hz to 20 kHz, so anything below 20 Hz is infrasonic. This term specifically describes subaudible waves, like some seismic signals or certain animal communications. Audible sound covers the 20 Hz to 20 kHz range, ultrasonic refers to frequencies above 20 kHz, and hypersonic is a term used for very high-frequency sounds beyond ultrasound in some contexts. So, for frequency less than 20 Hz, infrasonic is the right label.