Question

a periodic wave travels outward from a source. the waves frequency can be changed. the speed that the wave moves forward does not change. complete the statement. if the frequency of the wave is decreased, its wavelength will increase decrease stay the same

Explanation:

Step1: Recall wave - speed formula

The wave - speed formula is $v = f\lambda$, where $v$ is the wave speed, $f$ is the frequency, and $\lambda$ is the wavelength.

Step2: Analyze the relationship

Given that $v$ is constant ($v = f\lambda$ implies $\lambda=\frac{v}{f}$). When $f$ decreases and $v$ is fixed, $\lambda$ must increase.

Answer:

increase