Wavelength is the distance between two successive crests or troughs of a wave, measured in metric units such as meters, nanometers, or millimeters. Frequency is always expressed in hertz (Hz), which means 'per second.' The wavelength equation is Wavelength = Speed / Frequency, where speed can be calculated using various units like meter per second, kilometers per hour, or miles per hour. The equation helps calculate wavelength depending on the given information about velocity and frequency. Examples illustrate how to use the wavelength equation to calculate wavelength from speed and frequency, as well as calculating frequency and speed from wavelength. Additionally, the relationship between wavelength and frequency is discussed, showing an inverse proportional relationship. This understanding is crucial for applying the wavelength equation in various scenarios, including wireless networks like Wi-Fi.