Sound with frequencies below and above the audible frequency range are known as ________.

A. Feeble sound

B. Infrasound

C. Parasound

D. Ultrasound

Choose the correct answer from the options given below:

The correct answer is - Infrasound and Ultrasound

Key Points

• Infrasound
  • Infrasound refers to sound waves with frequencies below 20 Hz, which are below the audible range of human hearing.
  • These low-frequency sounds are often used in various scientific fields to monitor natural phenomena like earthquakes and volcanic activity.
• Ultrasound
  • Ultrasound refers to sound waves with frequencies above 20,000 Hz, which are above the audible range of human hearing.
  • Common applications of ultrasound include medical imaging (ultrasound scans) and industrial non-destructive testing.

Additional Information

• Audible Frequency Range
  • The audible frequency range for humans is typically between 20 Hz and 20,000 Hz.
  • Within this range, humans can perceive sounds of varying pitches, from the low rumble of a bass drum to the high pitch of a whistle.
• Applications of Infrasound
  • Infrasound is used in seismology to detect earthquakes and in volcanology to monitor volcanic eruptions.
  • It is also used in animal communication; some animals like elephants use infrasound to communicate over long distances.
• Applications of Ultrasound
  • Ultrasound is widely used in medical diagnostics, such as in prenatal imaging and echocardiograms.
  • In industrial applications, ultrasound is used for non-destructive testing to detect flaws in materials.