It is equal to the velocity of the wave, divided by the frequency. Wavelength is expressed in units of meters (m). λ = wavelength, the distance between wave crests (m). v = wave velocity, the speed that waves are moving in a direction (m/s).f = frequency, the wave crests that go through a point in a certain time (cycles/s or Hz). Wavelength Formula Questions: 1) The speed of sound is about 340 m/s.Find the wavelength of a sound wave that has a frequency of 20.0 cycles per second (the low end of human hearing). Answer: The wave velocity v = 340 m/s, and the frequency f = 20.0 cycles/s. = wavelength, the distance between wave crests (m). v = wave velocity, the speed that waves are moving in a direction (m/s). f = frequency, the wave crests that go through a point in a certain time (cycles/s or Hz). Wavelength Formula Questions: 1) The speed of sound is about 340 m/s.