Particle-like properties of light.
Light also behaves as if it consists of discrete particles or quanta called photons .
Each photon has a fixed quantity of energy which is inversely proportional to the wavelength of light. For example, a photon of violet light has nearly twice as much energy as a photon of red light. The sun radiates the full spectrum of electromagnetic energy. The atmosphere acts as a selective window that allows visible light to pass through while screening out a substantial fraction of other radiation. The visible range of light is the radiation that drives photosynthesis.