speed at which a wave travels. Wave speed is related to wavelength, frequency, and period by the equation wave speed = frequency x wavelength. The most commonly used wave speed is the speed of visible light, an electromagnetic wave. Wave speed can be determined if certain properties of the wave are known, such as wavelength, period and frequency. The speed of the wave is calculated as a ratio of one wavelength to one period of the wave. It can also be calculated as the product of the wavelength and the frequency. Increasing either wavelength or the frequency increases the speed of waves. In waves such as light, however, the speed remains constant in a given medium, while increasing one of the variables, such as wavelength, causes a decrease in the other variable, which is frequency