Here are some examples of wavelength:

Example 1: Yellow Light

All visible light corresponds to a wavelength range of 400 - 700 nanometers (nm).  Yellow light has a wavelength of about 570 nanometers.

wavelength
Wavelength (nm)
Example 2: Infrared Light

Energy whose wavelength is too long to see is "redder than red" or infrared.  Infrared radiation has wavelengths between 700 nm and 1 millimeter (mm).  In infrared the detected radiation is turned into an image on a screen, hotter objects showing up brighter.

image of small dog taken in mid-infrared light
Image of a small dog taken in mid-infrared ("thermal") light
Example 3: Radio Waves

Radio waves have the longest wavelengths in the electromagnetic spectrum.  Wave lengths range from 10 centimeters (cm) to 10,000 kilolometers (km).

radio wave region of teh electromegnetic spectrum
Radio Wave Region of the Electromagnetic Spectrum

The following concepts are not wavelength but are often confused with it:

Not an example Frequency

Not a wavelength but an attribute of a wave denoting how many complete wave cycles pass-by in a second.



Not an example Amplitude

Not a wavelength but an attribute of a wave denoting an oscillation or the maximum displacement of a wave.