Hertz (Hz)

Definition

Hertz (Hz) is the unit of frequency in the International System of Units (SI), representing one cycle per second. It is commonly used to describe the frequency of electromagnetic waves, including light.

5 Must Know Facts For Your Next Test

1. 1 Hz is equal to one cycle per second.
2. The frequency of visible light ranges from approximately 4 × $10^{14}$ Hz to 7.5 × $10^{14}$ Hz.
3. Higher frequencies correspond to higher energy electromagnetic waves.
4. Frequency (in Hz) and wavelength are inversely related: $c = \lambda \nu$, where c is the speed of light, $\lambda$ is the wavelength, and $\nu$ (frequency) is in Hz.
5. Hertz can be used to measure various types of waves, including sound waves and radio waves, but in chemistry, it often relates to electromagnetic radiation.

Review Questions

• What does one Hertz represent?
• How are frequency and wavelength related in terms of electromagnetic energy?
• What range of frequencies does visible light fall into?

Related terms

Wavelength: The distance between successive crests of a wave, typically measured in meters for electromagnetic waves.

Electromagnetic Spectrum: The range of all types of electromagnetic radiation, from radio waves to gamma rays.

$c = \lambda \nu$: $\c = \lambda \nu$ represents the equation relating the speed of light (c), wavelength ($\lambda$), and frequency ($\nu$) for electromagnetic waves.