What is light energy? Light energy is a kind of electromagnetic radiation that includes wavelengths that the average person can see. Kinetic energy, such as light, is a form of kinetic energy. It is made up of particles with wave-like properties, such as photons. Because of the heating effect, light energy is created.
Photons are little energy packets produced by light. The creation of photons occurs when an object’s atoms are heated. The heat excites the electrons, causing them to produce more energy. This energy is released in the form of a photon, and as the material heats up, more photons are emitted.
As it moves, light energy takes the form of a wave. Whatever the case may be, it is necessary to transport light energy. This is why light energy may travel across space without needing to pass through air, whereas sound waves must pass through solids, liquids, or gases. Light energy is extremely rapid and moves at a much faster rate than other forms of energy.
Our sense of sight can detect light, which is a kind of energy. It is composed of electromagnetic radiation and follows a straight route. We must use the term “light” at least ten times per day!!
Have you ever considered how much energy we get from light? We are surrounded by light. It can tan or burn our skin, as well as melt metals and cook our food. Until the 1950s, scientists had a significant barrier in understanding light energy.
For our purposes, we’ll refer to light as the electromagnetic spectrum, or EMS, which encompasses all of the frequencies of radiation. Light is a kinetic sort of energy since it is continually in motion and cannot be stored.
You may claim that light is virtually “pure” energy because it has no mass. Light is both a wave and a particle at the same time. The more energy is contained in light or electromagnetic radiation, the higher the frequency. The higher the frequency, the more energy each photon, or particle, has.
The electromagnetic energy that is visible to the human eye is referred to as light energy. Light energy is energy that flows in straight lines, termed rays, that radiate outward from the light source.
Intensity: The rate at which the source discharges light energy is known as the intensity of light. A watt is the power unit. It’s also known as brightness, which is defined as the rate at which light generates in a surface unit or the amount of energy per unit time per unit area.
Frequency: The number of crests that pass across a specific spot in a second is referred to as the frequency of light.
Wavelength: The space between two successive crests or troughs is referred to as the wavelength of light. Light waves travel at the same speed through the vacuum, because wavelength and frequency are nearly identical, the shorter the wavelength, the higher the frequency.
Polarization: Polarization is the process by which unpolarized light becomes polarised light. Light waves vibrate in multiple directions. As a result, they are classified as unpolarized light.
Phase: Phase refers to a certain point in the cyclic waveform’s time frame. When the waves are in phase, the intensity of light energy increases.
Light energy can be measured in a variety of ways:
The units of Angstrom and a nanometer are used to calculate the wavelength of light.
The frequency of light energy is calculated in Hertz units.
And the unit used to compute Light energy in electron volts (eV).
|Physical Units||Subjective Units|
|Light is a form of energy, and can be measured in energy units (joules, calories) or in quantum units (quanta, einsteins). Conversion between these units is wavelength dependent.||Light can be measured subjectively, based on the brightness seen by the human eye. Units include candles, lumens, footcandles and lux.|
|Power is the rate at which light is generated, transmitted or absorbed, and is measured in watts (1 watt = 1 joule sec-1) or einsteins sec-1||Luminous flux is equivalent to power. A source of one candle gives off a luminous flux of one candle power or 4π lumens.|
|Light intensity is measured for example with a LICOR light meter or a QSL (quantum scalar irradiance) meter. (the QSL type is considered more accurate because of its spherical rather than flat plate collector).||The intensity at a distance of: one foot from a standard candle is one footcandle|
There are different sorts of light energy. They are as follows:
Visible light: Light that can be seen with the human eye is known as visible light. It’s an electromagnetic energy kind. The sun is the source of visible light. Lanterns, flashlights, and light bulbs, among other things, can emit it.
Infrared light: Infrared light is a type of electromagnetic energy that generates heat. Infrared light is used in TV remote controls. They make their way from the controller to the television.
Ultraviolet light: Ultraviolet light: These are brief light waves that doctors employ to image within our bodies to detect fractures in our bones. X-rays are used by dentists to determine the depth of tooth decay.
Light energy can be used in a variety of ways. It is a type of electromagnetic radiation that can be seen with the human eye. However, there are several economic and scientific applications for light energy, some of which are described here.
Food: For all living species, light is the only source of food generation. Except for a few chemotrophic species like bacteria, all organisms rely on light for energy and nourishment.
Vision: Because of the presence of eyes, any organism can see the items around them. However, without light, these may be ineffective. When light falls on the image, the image is received by the eyes, and the information is transferred to the brain. As a result, light allows us to view the items around us.
Health: Sunlight also offers Vitamin D, which aids in the strengthening of bones.
Electronics: Solar panels transform light energy into electrical energy by storing it in the form of light energy. Electric light energy is suitable for household use because it is both environmentally benign and cost-effective.
Colors: Colors make the world beautiful, and light allows all of these colors to existing. The light is made up of several spectra, each of which has its color, which is referred to as VIBGYOR.
In a vacuum, the speed of light is defined as 299 792 458 m/s (approx. 186,282 miles per second). Because the meter is now defined in terms of the speed of light, the speed of light has a fixed value in SI units. In a vacuum, all kinds of electromagnetic radiation travel at the same speed.
The frequency of light energy is calculated in Hertz units. And the unit used to compute Light energy in electron volts (eV). There are many different sorts of light energy. In a vacuum, the speed of light is defined as 299 792 458 m/s (approx. 186,282 miles per second).
Photons are little energy packets produced by light. The creation of photons occurs when an object’s atoms are heated. The more energy is contained in light or electromagnetic radiation, the higher the frequency.
Galileo and Romer are two of the most famous scientists of all time. Throughout history, various physicists have attempted to measure the speed of light. In the seventeenth century, Galileo attempted to measure the speed of light.
Ole Romer, a Danish physicist, undertook an early experiment to measure the speed of light in 1676. Romer used a telescope to study Jupiter’s and one of its moons, Io’s, movements. He determined that light takes around 22 minutes to traverse the diameter of Earth’s orbit, based on inconsistencies in the apparent period of Io’s orbit.
Its magnitude, however, was unknown at the time. Romer would have predicted a speed of 227 000 000 m/s if he had understood the diameter of the Earth’s orbit.
Hippolyte Fizeau produced a more precise measurement of the speed of light in Europe in 1849. Fizeau aimed a light beam at a mirror located several kilometers distant. In the path of the light beam as it traveled from the source through the mirror and back to its origin, a rotating cogwheel was installed.
Fizeau discovered that the beam would pass through one gap in the wheel on the way out and the next gap on the way back at a given rate of rotation. Fizeau calculated the speed of light as 313 000 000 m/s using the distance to the mirror, the number of teeth on the wheel, and the rate of rotation.
In 1862, Léon Foucault conducted an experiment using rotating mirrors to reach a figure of 298 000 000 m/s. From 1877 until he died in 1931, Albert A. Michelson conducted tests on the speed of light.
In 1926, he improved Foucault’s methodology by measuring the time it took light to travel from Mount Wilson to Mount San Antonio in California using improved rotating mirrors. A speed of 299 796 000 m/s was calculated using exact measurements.
In different transparent substances containing ordinary stuff, the effective velocity of light is lower than in a vacuum. The speed of light in water, for example, is about 3/4 of that in a vacuum.
The Sun is the nearest star to Earth, and it emits light energy. The Sun is the primary source of light on Earth. Fire has always been a significant source of illumination for people, from ancient campfires to modern kerosene lamps. Electric lighting has effectively supplanted firelight as a result of the development of electric lights and power systems.
Electromagnetic radiation is produced in massive quantities by the sun. Only a small portion of this energy, known as ‘visible light,’ is visible to humans. Waves describe the passage of solar energy. By measuring the wavelength and the distance between consecutive wavelength places, scientists can determine the wave energy (from crest to crest and trough to trough).
The sun emits a variety of electromagnetic waves, including visible light. All conceivable radiation frequencies are defined by the electromagnetic spectrum. It depicts ultraviolet and x-rays, as well as other types of electromagnetic radiation emitted by the sun.
Light energy is a sort of kinetic energy capable of causing different types of light to be visible to human vision. Light is electromagnetic radiation that is emitted by heated things such as lasers, bulbs, and the sun.
Photons are tiny energy packets that makeup light. When the atoms of an object are heated, photons are produced, and this is how photons are created. The heat excites the electrons, which increases energy. The energy is released in the form of a photon, and as the substance heats up, more photons are emitted.
When light travels, it does it in the form of a wave. However, it is necessary to bring the energy along to travel. This is why light can move through space without the presence of air. Because sound waves must travel through solids, liquids, and gases, this is not the case. Light energy is extremely rapid and can travel quicker than anything else. 186,282 miles per second is the speed of light.
The sun emits several different types of electromagnetic radiation, including visible light. The electromagnetic spectrum is the range of all conceivable radiation frequencies. It depicts several types of electromagnetic radiation, such as ultraviolet and X-rays, rising from the sun.
Within the electromagnetic spectrum, distinct types of radiant energy from the sun have been separated, and the difference between wavelengths indicates the quantity of energy carried by them.
Light energy is measured in joules and is a type of energy. In physics, light is defined as electromagnetic radiation of any wavelength; however, the concept of light is commonly limited to a specific wavelength range (about 400-700 nm) that is visible to the human eye. The electromagnetic spectrum’s visible light is specifically referred to as the latter.
The visible light spectrum includes the parts of the electromagnetic spectrum related to mammalian vision and photosynthesis in plants and other photosynthetic organisms. When it comes to the sense of sight, the earth’s atmosphere, for example, screens out sunlight while allowing visible light to flow through.
It is the visible light that the human eye detects. Photosynthesis is also powered by visible light. The wavelengths of visible light that are most effectively absorbed by chlorophylls are blue and red. Some species can emit light. Bioluminescence is the term for this talent.
Throughout history, physicists have sought to measure the speed of light. Light takes 22 minutes to cover the circumference of Earth’s orbit, according to Ole Romer. In 1862, Léon Foucault calculated a figure of 298 000 000 m/s using revolving mirrors. 186,282 miles per second is the speed of light. The human eye can detect visible light, which is also the light that triggers photosynthesis. Bioluminescence refers to the ability of some organisms to emit light.
There are numerous light sources. A body produces a specific spectrum of black-body radiation at a specific temperature. When measured in wavelength units, the radiation emitted by the Sun’s chromosphere at around 6,000 kelvins (5,730 degrees Celsius; 10,340 degrees Fahrenheit) peaks in the visible part of the electromagnetic spectrum, accounting for roughly 44 percent of the sunlight energy that reaches the ground.
Incandescent light bulbs are another example, as they only produce about 10% of their energy as visible light and the rest as infrared. The blazing solid particles in flames have long been a common source of thermal light, but they also produce the majority of their radiation in the infrared and ultraviolet ranges.
For comparatively cool things like humans, the apex of the black-body spectrum lies in the deep infrared, at roughly a 10-micrometer wavelength. As the temperature rises, the peak shifts to shorter wavelengths, giving a red glow at first, then a white glow, and finally a blue-white color as the peak travels from the visible to the ultraviolet.
When metal is heated to a “red” or “white” temperature, these colors appear. Except in stars, blue-white thermal emission is rare (the pure-blue hue observed in a gas flame or a welder’s torch is due to molecular emission, mainly by CH radicals) (emitting a wavelength band around 425 nm and is not seen in stars or pure thermal radiation.
Atoms have certain energies for emitting and absorbing light. This results in “emission lines” in each atom’s spectrum. Light-emitting diodes, gas discharge lamps (such as neon lamps and neon signs, mercury-vapor lamps, and so on), and flames are examples of spontaneous emission (light from the hot gas itself so, for example, sodium in a gas flame emits characteristic yellow light). Emission can be stimulated in other ways, for as with a laser or a microwave maser.
A free-charged particle, such as an electron, can decelerate and emit visible light. This includes cyclotron radiation, synchrotron radiation, and bremsstrahlung radiation. Cherenkov radiation is produced by particles traveling faster than the speed of light across a material.
Chemoluminescence is the process by which some compounds produce visible radiation. This is known as bioluminescence in living organisms. Fireflies, for example, use this method to produce light, and boats traveling over water can disturb plankton, resulting in a blazing wake.
Fluorescence is the process of certain compounds producing light when they are illuminated by higher intense radiation. After being excited by higher intense radiation, some substances progressively release light. Phosphorescence is the term for this phenomenon.
It is also possible to stimulate phosphorescent materials by bombarding them with subatomic particles. One example is cathodoluminescence. This mechanism is found in television sets and computer monitors that use cathode ray tubes.
Because of its propensity to heat up, sunlight aids in the drying of wet clothes, the soil, forests, air, and rocky surfaces. Light also aids the evaporation of water from seas and ponds. This drying is beneficial in two ways to live on the planet:
The water cycle is a system for recycling fresh water on the earth’s surface for drinking and agriculture. Clouds are formed when surface water evaporates.
These clouds break into raindrops, bringing fresh water back to the earth’s surface. As a result of the rain, we have fresh water to drink as well as irrigation.
We would have no water to drink if the water cycle had not occurred, as all of the water on the planet would have remained in the ocean.
Our environment is kept clean by the sun. Sunlight keeps the environment clean and tidy by inhibiting the growth of weeds, algae, and other germs.
The sun dries off deceased bodies and other waste materials, causing them to lose mass and deteriorate (decrease in amount).
There are two primary sets of units used to measure light:
Photometry measures light with wavelength weighted concerning a defined model of human brightness perception, whereas radiometry measures light power at all wavelengths. Photometry can be used to quantify Illumination (lighting) designed for human use, for example.
The photometry units differ from other physical unit systems in that they account for how the human eye reacts to light. The human eye’s cone cells are divided into three types, each of which respond differently across the visible spectrum, with the cumulative response peaking at roughly 555 nm.
As a result, two sources of visible light with the same intensity (W/m2) may not necessarily appear to be equally bright. Photometry units are meant to account for this, and as a result, they provide a more accurate depiction of how “bright” a light appears than raw intensity.
They are used to determine how to best generate sufficient illumination for various jobs in both indoor and outdoor environments by a metric called luminous effectiveness, which is related to raw power.
Photocells and charge-coupled devices (CCDs) tend to respond to some infrared, ultraviolet, or both of the wavelengths measured by photocell sensors. Without filters, which can be expensive, photocells and charge-coupled devices (CCDs) tend to respond to some infrared, ultraviolet, or both of the wavelengths measured by photocell sensors.
Maxwell’s equations can be used to describe how light exerts physical pressure on objects in its path, but the particle aspect of light makes it easier to understand: photons impact and transmit their momentum. The power of a light beam divided by c, the speed of light, equals light pressure. The effect of light pressure on common objects is insignificant due to the size of c.
A one-milliwatt laser pointer, for example, exerts a force of around 3.3 piconewtons on the item being lighted; hence, laser pointers could raise a US penny, but it would take about 30 billion 1-mW laser pointers to do so.
The influence of light pressure is particularly important in nanometer-scale applications, such as nanoelectromechanical systems (NEMS), and utilizing light pressure to drive NEMS mechanisms and flip nanometer-scale physical switches in integrated circuits is an active area of research.
At bigger scales, light pressure can drive asteroids to spin faster, acting like the vanes of a windmill on their uneven shapes. Solar sails, which might be used to speed spaceships in space, are also being researched.
Although light pressure was often thought to be the cause of the Crookes radiometer’s motion, this is erroneous; the characteristic Crookes rotation is caused by a partial vacuum. This is not to be confused with the Nichols radiometer, in which light pressure causes the (slight) motion induced by torque (albeit not enough for full rotation against friction).
In 1909, Einstein predicted the development of “radiation friction” as a result of light pressure, which would obstruct matter mobility." “Radiation will put pressure on both sides of the plate,” he added. When the plate is at rest, the pressure forces on both sides are equal.
When it’s moving, though, more radiation is reflected on the surface that’s in front of it (the front surface) than on the back surface. As a result, the force of backward acting pressure exerted on the front surface is greater than the force of backward acting pressure exerted on the rear surface.
As a result of the two forces, there is still a force that opposes the plate’s motion and grows in proportion to the plate’s velocity. In a nutshell, we’ll name the ensuing ‘radiation friction.’ "
Light momentum is usually matched with its motion direction. However, with evanescent waves, for example, momentum is transverse to the propagation direction.
Optics is the study of light and how light interacts with matter. Observing and studying optical phenomena such as rainbows and the aurora borealis can provide a wealth of information about the nature of light.
The wavelength of light varies when it crosses the boundary between a vacuum and another medium, or between two different media, while the frequency remains constant. If the light beam is not orthogonal (or rather normal) to the boundary, a change in wavelength causes the beam to change direction. Refraction is the term for this change in direction.
Lenses’ refractive qualities are commonly employed to control light and adjust the perceived size of images. This manipulation can be done with magnifying glasses, spectacles, contact lenses, microscopes, and refracting telescopes.
When viewed from a shallow angle, the straw dipped in water seems bent and the ruler scale appears compressed due to refraction.
The bending of light beams as they pass through a surface between two transparent materials is known as refraction. Snell’s Law states: where 1 is the angle between the ray and the surface normal in the first medium, 2 is the angle between the ray and the surface normal in the second medium, n1 and n2 are the indices of refraction, n = 1 in a vacuum and n > 1 in a transparent substance, and n1 and n2 are the indices of refraction, n = 1 in a vacuum and n > 1 in a transparent.
In physics, the term “light” can refer to electromagnetic radiation of any wavelength, visible or not, regardless of wavelength.
Gamma rays, X-rays, microwaves, and radio waves are all light in this sense. Intensity, propagation direction, frequency or wavelength spectrum, and polarisation are the basic qualities of light. One of the fundamental constants of nature is its speed in a vacuum, which is 299 792 458 meters per second (m/s).
Visible light, like all types of electromagnetic radiation, is propagated by massless elementary particles called photons, which constitute electromagnetic field quanta and may be examined as both waves and particles. Optics, or the study of light, is an important research subject in modern physics.
Light, often known as visible light, is electromagnetic radiation that falls within the region of the electromagnetic spectrum that the human eye can perceive. Between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths), visible light is characterized as having wavelengths in the range of 400–700 nanometers (nm) (with shorter wavelengths).
Radio waves, microwaves, infrared, the visible spectrum that we see as light, ultraviolet, X-rays, and gamma rays are all types of electromagnetic radiation (EMR). Static electric, magnetic, and near-field fields are not included in the term “radiation.”
EMR behavior is determined by its wavelength. Wavelengths are shorter at higher frequencies and longer at lower frequencies. When EMR interacts with single atoms and molecules, the amount of energy per quantum it contains determines how it behaves.
In the visible light range, EMR consists of quanta (called photons) that are at the lower end of the energies that can cause electronic excitation within molecules, resulting in changes in the molecule’s bonding or chemistry.
Because its photons no longer have enough individual energy to cause a lasting molecular change (a change in conformation) in the visual molecule retinal in the human retina, EMR becomes invisible to humans (infrared) at the lower end of the visible light spectrum. This change triggers the sensation of vision.
Animals that are sensitive to different forms of infrared, but not through quantum absorption, exist. Infrared sensing in snakes is based on a type of spontaneous thermal imaging in which infrared radiation raises the temperature of tiny packets of cellular water. These animals detect EMR in this range because it induces molecular vibration and thermal effects.
UV light is invisible to humans above the visible light spectrum, mostly because it is absorbed by the cornea below 360 nm and the internal lens below 400 nm. Furthermore, the rods and cones in the human eye’s retina are unable to detect very short ultraviolet wavelengths (below 360 nm) and are thus destroyed by ultraviolet.
Many creatures with non-lens eyes (such as insects and shrimp) can detect ultraviolet light using quantum photon-absorption techniques, which are similar to how humans detect visible light.
Various sources classify visible light as ranging from 420–680 nm to 380–800 nm. People can see infrared wavelengths up to 1,050 nm under ideal laboratory settings, and children and young adults can see ultraviolet wavelengths down to about 310–313 nm.
Photomorphogenesis is a process in which the color spectrum of light influences plant growth.
Optics is the scientific study of light. One of the fundamental constants of nature is its speed in a vacuum, which is 299 792 458 meters per second (m/s). Radio waves, microwaves, infrared, the visible spectrum that we see as light, ultraviolet, X-rays, and gamma rays are all types of electromagnetic radiation (EMR). The wavelength of EMR influences its behavior higher frequencies to have shorter wavelengths, whereas lower frequencies have longer wavelengths.
An anatomist named Pierre Gassendi (1592–1655) devised a particle theory of light, which was published after his death in the 1660s. At a young age, Isaac Newton examined Gassendi’s work and favored his viewpoint over Descartes’ plenum theory. In his 1675 paper, The Hypothesis of Light, he claimed that light was made up of corpuscles (matter particles) that were emitted in all directions from a source.
One of Newton’s counter-arguments to light’s wave nature was that waves were known to bend around obstructions, whereas light only traveled in straight lines. He did, however, explain the phenomenon of light diffraction (which Francesco Grimaldi had observed) by permitting a light particle to form a localized wave in the aether.
Newton’s theory could predict light reflection, but it could only explain refraction by assuming mistakenly that light accelerates when it enters a denser material because the gravitational force is higher. In his book Optics, published in 1704, Newton provided the final version of his theory.
During the 18th century, his reputation helped the particle theory of light gain traction. According to Laplace’s particle theory of light, a body could be so enormous that light could not escape it. In other words, it would become a black hole, as it is presently known.
The idea that light might be polarised was qualitatively explained for the first time by Newton using the particle theory. In 1810, Étienne-Louis Malus developed a mathematical polarisation particle theory. In 1812, Jean-Baptiste Biot demonstrated that this hypothesis explained all known polarisation occurrences. Polarization was thought to be proof of the particle hypothesis at the time.
In his 1665 work Micrographia, Robert Hooke (1635–1703) created a “pulse theory” to explain the genesis of colors, comparing the dispersion of light to that of waves in water (“Observation IX”). Hooke proposed in 1672 that light’s vibrations may be perpendicular to the propagation direction.
In 1678, Christiaan Huygens (1629–1695) devised a mathematical wave theory of light, which he presented in 1690 in his Treatise on Light. In the medium term the luminiferous aether, he argued that light was released in all directions as a succession of waves. Because waves are not affected by gravity, it was expected that as they entered a denser medium, they would slow down.
Light waves, like sound waves, could interfere with each other, according to wave theory (as noted around 1800 by Thomas Young). Young demonstrated that light behaves as waves using a diffraction experiment. He also argued that different wavelengths of light created distinct colors and that color vision was explained in terms of three-colored receptors in the eye.
In an attempt to explain black-body radiation in 1900, Max Planck proposed that, while the light was a wave, it could only gain or lose energy in finite amounts related to its frequency. These “lumps” of light energy were dubbed “quanta” by Planck (from a Latin term meaning “how much”).
Albert Einstein proposed the concept of light quanta to explain the photoelectric effect in 1905, implying that these light quanta had a “real” existence. Arthur Holly Compton demonstrated in 1923 that the wavelength shift observed when low-intensity X-rays scattered from electrons (known as Compton scattering) could be described by a particle theory of X-rays rather than a wave theory.
Gilbert N. Lewis coined the term “photon” to describe these light quanta particles in 1926. Eventually, modern quantum mechanics came to see light as both a particle and a wave (in some senses) and as a phenomenon that is neither a particle nor a wave (in other senses) (which are macroscopic phenomena, such as baseballs or ocean waves).
Instead, current physics views light as something that can be described using equations that are suited for one sort of macroscopic metaphor (particles) and another macroscopic metaphor (water waves), but that cannot be fully visualized.
Following are the important questions that usually people ask about light energy:
Light is an energy form. Light is essential in our existence because without it, we would have to survive in the dark, going in circles with no beginning or finish. We all know that the sun is the most natural source of light, but other sources of light include electric bulbs, candles, torches, kerosene lamps, and so on.
Light energy is a wavelength of electromagnetic radiation that can be perceived by the human eye. It is a kinetic energy kind.
Waves are used to transport light energy. Light moves at a breakneck speed; in fact, nothing travels faster than light.
Photons, which are like small packets of energy, make up light. The movement of atoms produces photons when an object’s atoms heat up. The more photons produced by an object, the hotter it is.
Light energy is utilized to aid vision, either naturally through the Sun or fire, or artificially through candles and light bulbs.
Electromagnetic energy is another name for light energy. Light has two wavefronts since it is an electromagnetic wave.
Gamma rays, X-rays, microwaves, and radio waves are all light in this sense. Intensity, propagation direction, frequency or wavelength spectrum, and polarisation are the basic qualities of light. One of the fundamental constants of nature is its speed in a vacuum, which is 299 792 458 meters per second (m/s).
Light is a Particle. Now that light’s dual nature as “both a particle and a wave” has been established, the fundamental theory of light has progressed from electromagnetics to quantum mechanics. Light is a particle (photon), and the passage of photons is a wave, according to Einstein.
The sun, stars, and fires are all examples of natural light sources. Natural light sources are so named because they naturally emit light. Lamps, torches, and computer screens are examples of artificial light sources.
When light bounces off an object, it is called reflection. A smooth surface reflects light at the exact angle that it strikes it. Reflected light rays go in the same direction over a flat surface. Specular reflection is the term for this. Reflected light rays disperse in all directions over a rough surface.
Photons are little energy packets produced by light. The creation of photons occurs when an object’s atoms are heated. This energy is released in the form of a photon, and as the material heats up, more photons are emitted. Until the 1950s, scientists had a significant barrier in understanding light energy. Light energy can be measured in a variety of ways, including wavelength, frequency, and phase. It’s a type of electromagnetic radiation that only the human eye can see. In a vacuum, the speed of light is defined as 299 792 458 m/s (approx. 186,282 miles per second). In a vacuum, all kinds of electromagnetic radiation travel at the same speed.