The length of its wavelength.

A period of a wave is the time required for one complete cycle; one up motion (one crest) and then one down motion (one trough). Therefore, the distance between two adjacent crests or troughs is equal to the distance that wave travels in one period.

A period of a wave is the time required for one complete cycle; one up motion (one crest) and then one down motion (one trough). Therefore, the distance between two adjacent crests or troughs is equal to the distance that wave travels in one period.