Question

as the wavelength of a wave increases, the frequency... increases. decreases. does not change.

Explanation:

Step1: Recall wave - speed formula

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

Step2: Analyze relationship

For a wave in a given medium, the wave speed $v$ is constant. Rearranging the formula gives $f = \frac{v}{\lambda}$. So, when $\lambda$ increases, since $v$ is constant, $f$ (frequency) decreases.

Answer:

B. decreases.