Light

Light is something that causes us to see things. We can see sunrise every morning. We can see many stuff in our room, our home, school or office. We could see many color at the rainbow. Actually when we see things, it reflecting light from light sources, or could be shining itself. So that, if there are no light at someplace, we couldn't see enything, even if many things in there.


Light plays an important role in life. Light is electromagnetic radiation that is visible for human eye, and is responsible for the sense of sight. It has electromagnetic spectrum thst human eye can detect. Light shoots out in very high speed, it is 299,792,458 meters per second. It has two properties, both as wave and as rays. It called wave-particle duality. As rays, light could be reflected and refracted. As wave, light have interference, diffraction, and polarization.

The modern theory that explains the nature of light includes the notion of wave–particle duality, described by Albert Einstein in the early 1900s, based on his study of the photoelectric effect and Planck's results. Einstein asserted that the energy of a photon is proportional to its frequency. More generally, the theory states that everything has both a particle nature and a wave nature, and various experiments can be done to bring out one or the other. The particle nature is more easily discerned if an object has a large mass, and it was not until a bold proposition by Louis de Broglie in 1924 that the scientific community realised that electrons also exhibited wave–particle duality. The wave nature of electrons was experimentally demonstrated by Davisson and Germer in 1927. Einstein received the Nobel Prize in 1921 for his work with the wave–particle duality on photons (especially explaining the photoelectric effect thereby), and de Broglie followed in 1929 for his extension to other particles.