Frequency

Definition

Frequency is the number of oscillations or cycles that occur in a unit of time, typically measured in Hertz (Hz). It represents how often a repeating event such as a sound wave occurs per second.

5 Must Know Facts For Your Next Test

1. Frequency is inversely proportional to the wavelength of a sound wave: higher frequency means shorter wavelength and vice versa.
2. The speed of sound in a medium is determined by both its frequency and wavelength, described by the equation $v = f \lambda$ where $v$ is speed, $f$ is frequency, and $\lambda$ is wavelength.
3. Human hearing typically ranges from about 20 Hz to 20,000 Hz; frequencies outside this range are inaudible to humans.
4. In different media, the same sound's frequency remains constant while its speed and wavelength may change.
5. Ultrasound refers to sound waves with frequencies above 20,000 Hz, which are used in medical imaging and other applications.

Review Questions

• What units are used to measure frequency?
• How does changing the medium affect the frequency of a sound wave?
• What is the relationship between frequency and wavelength?

Related terms

Wavelength:

The distance between successive crests or troughs of a wave.

Amplitude:

The maximum extent of a vibration or oscillation, measured from the position of equilibrium.

Speed of Sound:

$v = f \lambda$: The rate at which sound waves propagate through different mediums.