What is a wavelength?

What is a wavelength?

• A. Distance from crest to crest or trough to trough
• B. The height of the wave
• C. The number of waves per second
• D. The speed of the wave

Answer: (A)

Wavelength is the distance over which a wave’s pattern repeats. In a transverse wave, that means the distance from one crest to the next crest (or from one trough to the next trough). It’s not the height of the wave (that’s amplitude), not how many waves pass a point each second (frequency), and not how fast the wave travels (speed). For example, if successive crests are 2 cm apart, the wavelength is 2 cm. In light, different wavelengths correspond to different colors, with shorter wavelengths toward the blue/violet end and longer wavelengths toward the red end.

Wavelength is the distance over which a wave’s pattern repeats. In a transverse wave, that means the distance from one crest to the next crest (or from one trough to the next trough). It’s not the height of the wave (that’s amplitude), not how many waves pass a point each second (frequency), and not how fast the wave travels (speed). For example, if successive crests are 2 cm apart, the wavelength is 2 cm. In light, different wavelengths correspond to different colors, with shorter wavelengths toward the blue/violet end and longer wavelengths toward the red end.