Light consists of electromagnetic waves that travel at the same speed but possess different energy levels determined by their frequency, as explained by Planck's equation. The energy of light is related to its "internal vibration," with higher frequencies corresponding to higher energy. When light passes through a different medium, its frequency and energy remain constant, but its wavelength changes. The speed of light varies in different media, affecting the wavelength while keeping energy consistent. Understanding these principles clarifies how light behaves in various environments.
