Hertz

Definition

Hertz (Hz) is the unit of frequency, which measures the number of cycles or oscillations that occur per second. It is a fundamental concept in physics, particularly in the study of wave phenomena, such as sound waves and electromagnetic waves.

5 Must Know Facts For Your Next Test

1. Hertz is used to measure the frequency of various physical phenomena, including sound waves, electromagnetic waves, and the vibrations of objects.
2. In the context of simple harmonic motion, the frequency of oscillation is measured in Hertz, and is related to the period of the motion.
3. The energy in simple harmonic motion is directly proportional to the square of the frequency, as described by the equation $E = \frac{1}{2}kA^2$, where $k$ is the spring constant and $A$ is the amplitude of the motion.
4. The speed of sound waves is related to their frequency and wavelength through the equation $v = f\lambda$, where $v$ is the speed of sound, $f$ is the frequency, and $\lambda$ is the wavelength.
5. The normal modes of a standing sound wave are determined by the frequency of the wave, which must be an integer multiple of the fundamental frequency of the system.

Review Questions

• Explain how the concept of Hertz is used to describe the frequency of simple harmonic motion.
  • In the context of simple harmonic motion, the frequency of oscillation is measured in Hertz (Hz), which represents the number of complete cycles that occur per second. The frequency of simple harmonic motion is inversely proportional to the period of the motion, as described by the equation $f = \frac{1}{T}$, where $f$ is the frequency in Hertz and $T$ is the period in seconds. The frequency of simple harmonic motion is also directly related to the energy of the system, as the energy is proportional to the square of the frequency, as shown by the equation $E = \frac{1}{2}kA^2$.
• Describe how the concept of Hertz is used to understand the speed of sound waves and the normal modes of a standing sound wave.
  • The speed of sound waves is related to their frequency and wavelength through the equation $v = f\lambda$, where $v$ is the speed of sound, $f$ is the frequency in Hertz, and $\lambda$ is the wavelength. The normal modes of a standing sound wave are determined by the frequency of the wave, which must be an integer multiple of the fundamental frequency of the system. This means that the frequency of the sound wave, measured in Hertz, plays a crucial role in determining the patterns of constructive and destructive interference that create the normal modes of the standing wave.
• Analyze how the concept of Hertz can be used to make Fermi estimates and calculations related to wave phenomena.
  • The concept of Hertz can be used to make Fermi estimates and calculations related to wave phenomena, such as sound waves and electromagnetic waves. For example, one could estimate the frequency of a particular sound wave by considering the typical range of human hearing, which is approximately 20 Hz to 20,000 Hz. Similarly, one could estimate the frequency of visible light by considering the range of the electromagnetic spectrum, which extends from approximately 430 THz (violet) to 750 THz (red). These Fermi estimates and calculations rely on the fundamental understanding of Hertz as a unit of frequency, and how it relates to other wave properties like wavelength and speed.

Related terms

Frequency:

Frequency is the number of cycles or oscillations that occur per unit of time, typically measured in Hertz.

Period:

The period is the time taken for one complete cycle or oscillation to occur, and is the reciprocal of frequency.

Wavelength:

Wavelength is the distance between consecutive peaks or troughs of a wave, and is related to frequency and the speed of the wave.