The four characteristics that are all present at the same time for visible light are:
Wavelength: Wavelength refers to the distance between two consecutive peaks or troughs of a light wave. Each color of visible light corresponds to a specific range of wavelengths. For example, red light has longer wavelengths, while blue light has shorter wavelengths.
Frequency: Frequency represents the number of wave cycles that pass a given point in a second. It is measured in hertz (Hz). Frequency and wavelength are inversely related, meaning that as wavelength increases, frequency decreases, and vice versa.
Speed: The speed of light in a vacuum is a constant value of approximately 299,792,458 meters per second (often rounded to 3 x 10^8 m/s). This speed remains the same regardless of the wavelength or frequency of the light wave.
Energy: Visible light consists of photons, which are discrete packets of energy. The energy of a photon is directly proportional to its frequency and inversely proportional to its wavelength. Higher-frequency light, such as blue light, has more energy per photon than lower-frequency light, such as red light.
These four characteristics—wavelength, frequency, speed, and energy—coexist for visible light and are interconnected through various mathematical relationships. They collectively define the properties and behavior of light waves within the visible spectrum.