This occurrence advocated its wave-like behavior because if light was just a stream of particles, how could it bend around the sharp boundaries of the slit and continue moving similar to a water wave? He used it to describe the phenomenon where a single beam of light, when passed through a narrow slit, was able to split into different directions creating an interference pattern. The term ‘diffraction’ was first coined in the year 1660, by Italian physicist Francesco Grimaldi. However, the discovery of diffraction of light proved that it had wave-like qualities as well. Many of light’s behavior and properties led to the conclusion that it must be a stream of particles. Diffractionįor many years, scientists had debated on whether light is a linear stream of particles or a wave. Where V1 and V2 represent the different velocities of light in each medium, and n1 and n2 represent the refractive index of each medium.
Later, in 984 CE, a mathematician from Baghdad, by the name of Ibn Sahl, was able to derive the full equation for refraction as given below. While measuring the angle of refraction against the angle of incidence, as light passed through different media, he discovered that the angle of incidence of light was proportional to the angle of refraction.Īngle of incidence(i) ∝ angle of refraction(r) Refraction was first studied by the Roman scientist Ptolemy in the 2nd century CE. Stars too ‘twinkle’ due to the refraction of their light by the Earth’s atmosphere. This is why when a full spectrum beam of light is made to travel through a prism, each of its wavelengths are separated into the colors of the rainbow. This change of speed bends the light as it travels through the different mediums, causing the angle of refraction to be different to the angle of incidence.ĭifferent wavelengths of light also travel at different speeds, which causes them to bend at different angles. For example, light travels fastest in vacuum, slower through air, and even slower through water. Very smooth surfaces, such as mirrors, are able to almost completely reflect the incident light, thus allowing the viewer to see his/her own reflection on them.Īngle of incidence(i) = angle of refraction(r)Ī beam of light travels at different speeds through objects of different densities. The actual amount of light that is reflected depends on the composition and physical characteristics of the object.
Reflection is the phenomenon wherein a beam of light incident on an object bounces off, i.e., reflects of its surface. So let’s go ahead and find out what they are. These are natural phenomena that take place frequently in nature and find several different practical and scientific applications. Today, we shall be studying three important properties of light―reflection, refraction, and diffraction. This particle cum wave, which is also the fastest thing in the universe, has all the ingredients to make it fascinating to study it. Light too has managed to live up to our expectations by being one of the most wonderful elements in nature. Right from the dawn of civilization, we humans have always had a fascination with light. Solar glory, which is an optical phenomenon that resembles the iconic saint’s halo above the shadow of an observer’s head, occurs as a result of light back-scattering, which is a combination of reflection, refraction and diffraction of light towards its source, by a cloud of uniform sized water droplets.