Which term explains the separation of waves by wavelength as they propagate away from where they formed?

• A. Fetch
• B. Interference
• C. Dispersion
• D. Gravity Wave

Answer: (C)

Dispersion is the separation of waves by wavelength as they propagate away from where they formed. This happens because waves of different wavelengths travel at different speeds in a medium. For surface gravity waves in water, the speed depends on wavelength (and depth), so longer wavelengths can move faster than shorter ones. As a result, a wave group containing multiple wavelengths spreads out, with different wavelengths moving at different rates. Fetch refers to the distance wind travels across water and influences wave generation, not the spreading by wavelength. Interference is the superposition of waves that can create patterns but isn’t the mechanism that separates wavelengths. Gravity wave describes the type of wave, not the process of dispersion.