Frequency

Definition

Frequency is the number of wave cycles that pass a given point per unit of time, typically measured in Hertz (Hz). In astronomy, it is crucial for understanding the properties of electromagnetic radiation such as light.

5 Must Know Facts For Your Next Test

1. Higher frequency light has more energy than lower frequency light.
2. Frequency and wavelength are inversely related; as one increases, the other decreases.
3. Visible light frequencies range from approximately 430 terahertz (red) to 770 terahertz (violet).
4. Radio waves have the lowest frequencies on the electromagnetic spectrum while gamma rays have the highest.
5. The Doppler effect causes shifts in frequency due to relative motion between a light source and an observer.

Review Questions

• How does frequency relate to the energy of a wave?
• What happens to wavelength as frequency increases?
• Which type of electromagnetic radiation has higher frequency: X-rays or radio waves?

Related terms

Wavelength:

The distance between successive peaks or troughs of a wave.

Electromagnetic Spectrum:

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

Doppler Effect:

The change in frequency or wavelength of a wave in relation to an observer moving relative to the source of the wave.