Physics Light

Define?

The electromagnetic radiation that the human eye can see is known as "light," and it takes the form of this radiation. It also refers to the little portion of the electromagnetic spectrum and the energy emitted by stars like the sun.

Dividing Light:

The range of wavelengths and frequencies that make up electromagnetic radiation, light, and waves together constitute the spectrum of electromagnetic waves. Both the wavelength (distance between adjacent points on an individual wave) and the frequency (number of waves passing through a specific location in a second) of waves in the electromagnetic spectrum vary. The electromagnetic radiation that carries the most energy has the highest frequency and shortest wavelength.

The electromagnetic spectrum consists of the following waves and their wavelengths from longest to shortest:

1)Radio waves: from 100,000 kilometers to 1 meter.
2)Microwave: 10cm to 1mm.
3)Infrared (thermal radiation) - from 1 millimeter to 1 micron (that is, the size of the needle tip).
4)Visible light is between 700 and 400 nanometers (that's the size of single-celled organisms).
5)Ultraviolet - between 400 and 10 nanometers (i.e. molecular size).
6)X-rays: from 10 nanometers to 10 picometers (that's the size of atoms).
7)Gamma rays - from 10 picometers to 1 picometer (that is, the size of atomic nuclei).

In addition, visible light can be decomposed into its wavelength spectrum for each color. Different visible light wavelengths and frequencies are detected and interpreted as different colors by the human eye. Depending on the atom or molecule interacting with or emitting wavelengths of visible light, each substance will absorb, reflect, and/or emit electromagnetic radiation of different wavelengths. The eye and brain detect and distinguish different wavelengths of light by perceiving the surrounding world interacting with light as a particular set of colors, including red, orange, yellow, green, blue, indigo, and violet. Red has the longest wavelength of visible light and is near-infrared; violet has the shortest wavelength of visible light and is next to ultraviolet in the electromagnetic spectrum.

Theory of Light Through History:

While there is clear evidence that several ancient civilizations used simple optical instruments such as flat and curved mirrors and convex lenses, ancient Greek philosophers are usually credited with the first formal hypotheses about the nature of light. The conceptual hurdle of distinguishing human perception of visual effects from the physical nature of light has hindered the development of light theories. These early studies were dominated by the contemplation of the mechanism of vision. Pythagoras (c. 500 BCE) suggested that vision was caused by visual rays emanating from the eye and hitting objects, while Empedocles (c. 450 BCE) seems to have developed model vision, where light is emitted by both objects and the eye. Epicurus (c. 300 BC) believed that light is emitted from sources other than the eye, and that vision occurs when light bounces off objects and enters the eye. In his Optics, Euclid (about 300 BC) first put forward the concept of reflection and talked about how light travels in straight lines. Ptolemy (c. AD 100) made one of the first quantitative studies of the refraction of light as it passes from one transparent medium to another, tabulating pairs of incidence and transmission angles for combinations of multiple media. During the decline of the Greco-Roman kingdom, scientific progress shifted to the Islamic world. In particular, al-Mahmun, the seventh Abbasid caliph of Baghdad, founded the House of Wisdom (Bayt al-Hikma) in 830 AD. for the translation, study, and improvement of Hellenistic scientific and philosophical works. Among the earliest scholars were al-Khwarizmi and al-Kindi. As the "Philosopher of the Arabs," al-Kindi developed the idea of rectilinearly propagated light beams and talked about how vision works. In 1000, the Pythagorean model of light was abandoned and the model of rays emerged, which contained the basic conceptual elements of what is now known as geometric optics. In particular, Ibn al-Haytham (Latinized as Alhazen) in Kitab al-manazir (c. 1038; "Optics") correctly attributed vision to the passive perception of light rays reflected from objects, and not to the active emission of light rays of the eye. Additionally, he developed in-depth illustrations of the optical elements of the human eye and researched the mathematical aspects of how light reflects from spherical and parabola mirrors. Ibn al-Haytham's work was translated into Latin in the 13th century and had a motivating influence on the Franciscan friar and naturalist Roger Bacon. Bacon studied the propagation of light through simple lenses and is considered one of the first to describe the use of lenses for vision correction.

Dual Nature of Light:

The dual nature of light is because light has both wave and particle properties. This concept, known as wave-particle duality, has become an important discovery in physics and is a fundamental principle of quantum mechanics.

Wave Appearance:
Light exhibits wave properties such as:

Interference: When two or more light waves overlap, they can interfere constructively (the amplitudes add up) or destructively (the amplitudes cancel each other out). This phenomenon can be observed in interference patterns created for example in the double slit experiment.

Diffraction: Light waves can bend or propagate when they hit an obstacle or pass through a narrow gap. This behavior is called diffraction and causes light waves to move in a pattern.

Particle Appearance:
Light also behaves like a stream of individual particles called photons. Some important characteristics of particle appearance are:

Photons: Light can be thought of as a collection of small packets of energy called photons. Each photon carries a certain amount of energy that is proportional to its frequency. The formula E = hf, where h is the constant determined by Planck and f is the frequency of light, specifies the energy of a photon.

Quantization: The energy of light is quantized, meaning it can only exist in certain discrete amounts that correspond to the energy of individual photons. This is different from classical physics, where energy is assumed to be continuous.

Photoelectric Effect: The photoelectric effect observed when light interacts with certain materials demonstrate the particle nature of light. It involves ejecting electrons from the surface of a material when illuminated with light of sufficient energy. The intensity of the light determines the number of electrons emitted and the frequency of the light determines their kinetic energy.