Final answer:
The wavelength of a wave increases when its frequency decreases, due to their inverse relationship described by the wave equation.
Step-by-step explanation:
When the frequency of a wave decreases, the wavelength of the wave increases. This is because wavelength and frequency have an inverse relationship. To understand this relationship, we can refer to the wave equation which is v = f × λ, where v is the wave speed, f is the frequency, and λ (lambda) is the wavelength.
With the wave speed v remaining constant for a particular medium, if the frequency f goes down, then the wavelength λ must go up to keep the equation balanced. Therefore, as the frequency of a wave decreases, its wavelength gets longer.
When the frequency of a wave decreases, the wavelength increases. This relationship is called an inverse relationship, meaning that as one quantity increases, the other quantity decreases.
For example, if you imagine two waves passing by a stationary point, the wave with the lower frequency would have a longer wavelength, while the wave with the higher frequency would have a shorter wavelength. This can be observed in Figure B, where the top wave has a shorter wavelength but a higher frequency compared to the second wave.