Define ultrasound as sound with a frequency higher than 20 kHz

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IGCSE Physics - 3.4 Sound - Ultrasound

IGCSE Physics - 3.4 Sound

Ultrasound

Ultrasound is a type of sound wave that has a frequency higher than 20 kHz. This means that the frequency of an ultrasound wave is greater than 20,000 cycles per second.

Definition

Ultrasound: Sound waves with a frequency greater than 20 kHz.

Properties of Ultrasound

  • High Frequency: The defining characteristic of ultrasound.
  • Long Wavelength: Due to the high frequency, ultrasound waves have relatively long wavelengths.
  • Not Audible to Humans: The human ear cannot hear frequencies above 20 kHz.
  • Can Penetrate Materials: Ultrasound waves can travel through certain materials like water, air, and some solids.

Applications of Ultrasound

Ultrasound has a wide range of applications, including:

  1. Medical Imaging: Used in ultrasound scans to create images of internal body organs.
  2. Cleaning: Used in ultrasonic cleaners to remove dirt and grime from delicate objects.
  3. Sonar: Used by ships and submarines to detect objects underwater.
  4. Non-Destructive Testing: Used to check for flaws in materials without damaging them.
  5. Animal Navigation: Bats and dolphins use ultrasound for echolocation to navigate and find prey.

Table summarizing Ultrasound Properties

Property Value
Frequency Greater than 20 kHz
Wavelength Relatively long
Audibility to Humans Not audible
Penetration Can penetrate certain materials

Figure: Suggested diagram: A diagram showing a sound wave with a frequency higher than 20 kHz labeled as ultrasound. The diagram should also indicate that it is not audible to humans.

Suggested diagram: A diagram showing a sound wave with a frequency higher than 20 kHz labeled as ultrasound. The diagram should also indicate that it is not audible to humans.