Speed and wavelength are related how in a given medium?

• A. They are inversely related; as speed increases, wavelength decreases
• B. They are directly related; as speed increases, wavelength increases
• C. They are not related
• D. Wavelength determines speed regardless of frequency

Answer: (B)

The main idea is the wave relation v = f × λ. In a given medium, the speed of sound is dictated by the medium’s properties, while the frequency is set by the source and is essentially fixed. If the frequency stays the same and the wave’s speed increases, the wavelength must increase as well to keep the product f × λ equal to the speed. That makes speed and wavelength directly proportional in this scenario.

So as speed goes up, wavelength goes up too, which is why the correct choice says they are directly related. The other options don’t fit because speed is a property of the medium, and wavelength is the result of multiplying that speed by the frequency; changing one while the other remains fixed does not support an inverse or no relationship, and wavelength does not set the speed.