As frequency increases, wavelength ______.

As frequency increases, wavelength ______.

• A. Increases; Decreases
• B. Decreases; Increases
• C. Increases; Increases
• D. Decreases; Decreases

Answer: (A)

Frequency and wavelength are inversely related for a wave traveling in the same medium. The wave speed v stays constant, and the relationship is v = f × λ, where f is frequency and λ is wavelength. Rearranging gives λ = v / f. So if the frequency goes up, the wavelength must go down to keep the product f × λ equal to v. For light in vacuum, this means λ = c / f, so doubling the frequency halves the wavelength. This is why the correct completion is that wavelength decreases as frequency increases. The idea that wavelength increases with frequency would violate the constant-speed relationship, since a higher frequency cannot fit as many wave crests into the same distance if the speed is fixed.

Frequency and wavelength are inversely related for a wave traveling in the same medium. The wave speed v stays constant, and the relationship is v = f × λ, where f is frequency and λ is wavelength. Rearranging gives λ = v / f. So if the frequency goes up, the wavelength must go down to keep the product f × λ equal to v. For light in vacuum, this means λ = c / f, so doubling the frequency halves the wavelength.

This is why the correct completion is that wavelength decreases as frequency increases. The idea that wavelength increases with frequency would violate the constant-speed relationship, since a higher frequency cannot fit as many wave crests into the same distance if the speed is fixed.