Wave speed, wavelength, period, and frequency are locked by c equals f times lambda

Evidence

Suppose the wave in figure 2.1 is moving from left to right at speed c, and we track a given crest. The distance the crest would cover in time t is d = ct— distance equals velocity times time. The time between one crest and the next (one wavelength) passing a given point is called the period, τ. In that case d = λ and t = τ, and d = ct becomes λ = cτ. The inverse of the period is the number of repeats per second, which we call the frequency, f = 1/τ. Then, we can just as well write f λ = τ. — Eric J. Heller, Why You Hear What You Hear- An…, 131

Categorization

• DEFINE: Crisp derivation of the fundamental wave relation linking speed, wavelength, period, and frequency.