Photon energy - Wikipedia
It is proposed a photon energy-frequency relation \(E = h \nu/2\) is necessary for wavelength and frequency to energy relationships. The. Photon energy is the energy carried by a single photon. The amount of energy is directly proportional to the photon's electromagnetic frequency and inversely proportional to the wavelength. The higher the photon's frequency, the higher its energy. where f is frequency, the photon energy equation can be simplified to. I read in a book the following paragraph and there was no explanation: "The emission is a great flood of photons, their energy increases when their frequency .
So there's a photon, here's another photon. Basically, this is the problem. This is the main problem with wave particle duality, it's called.
The fact that light, and everything else, for that matter, can behave in a way that shows wavelike characteristics, it can show particle-like characteristics, there's no classical analog of this. We can't envision in our minds anything that we've ever seen that can do this, that can both behave like a wave and a particle.
So it's impossible, basically, to draw some sort of visual representation, but, you know, it's always good to draw something. So we draw our photons like this. And so, what I'm really saying here is, if you had a detector sitting over here that could measure the light energy that it receives from some source of light, what I'm saying is, if that detector was sensitive enough, you'd either get no light energy or one jump, or no light energy or, whoop, you absorbed another photon.
You couldn't get in between. If the quantum jump was three units of energy I don't want to give you a specific unit yet, but, say, three units of energy you could absorb, if that was the amount of energy for that photon, if these photons were carrying three units of energy, you could either absorb no energy whatsoever or you could absorb all three. You can't absorb half of it. You can't absorb one unit of energy or two units of energy. You could either absorb the whole thing or nothing.
That's why it's quantum mechanics. You get this discrete behavior of light depositing all its energy in a particle-like way, or nothing at all. Well, we've got a formula for that. The amount of energy in one photon is determined by this formula. And the first thing in it is Planck's constant. H is the letter we use for Planck's constant, and times f. It's a simple formula. F is the frequency.Wavelength frequency and energy
What is Planck's constant? Well, Planck was basically the father of quantum mechanics. Planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts. So Planck's constant is extremely small; it's 6. There aren't many other numbers in physics that small. Times the frequency -- this is regular frequency.
So frequency, number of oscillations per second, measured in hertz. So now we can try to figure out, why did physicists never discover this before?
And the reason is, Planck's constant is so small that the energy of these photons are extremely small. The graininess of this discrete amount of energy that's getting deposited is so small that it just looks smooth. You can't tell that there's a smallest amount, or at least it's very hard to tell. So instead of just saying 'three units,' let's get specific. For violet light, what's the energy of one violet photon? Well, the frequency of violet light is 7.
So if you take that number times this Planck's constant, 6. Five times ten to the negative 19th, that's extremely small. That's hard to see. That's hard to notice, that energy's coming in this discrete amount. I mean, water from your sink. Water flowing out of your sink looks continuous. We know there's really discrete water molecules in there, and that you can only get one water molecule, no water molecules, 10 water molecules, discrete amounts of these water molecules, but there's so many of them and they're so small, it's hard to tell that it's not just completely continuous.
The same is happening with this light. This energy's extremely small. Each violet photon has an extremely small amount of energy that it contributes. In fact, if you wanted to know how small it is, a baseball, a professional baseball player, throwing a ball fast, you know, it's about joules of energy.
If you wanted to know how many of these photons, how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed?
It would take about two million trillion of these photons to equal the energy in a baseball that's thrown. That's why we don't see this on a macroscopic scale.
Photons - Chemistry LibreTexts
The wavelength is defined as the distance between two peaks of the electric field with the same vector. The frequency of a photon is defined as how many wavelengths a photon propagates each second.
Unlike an electromagnetic wave, a photon cannot actually be of a color. Instead, a photon will correspond to light of a given color. As color is defined by the capabilities of the human eye, a single photon cannot have color because it cannot be detected by the human eye.
In order for the retina to detect and register light of a given color, several photons must act on it. Only when many photons act in unison on the retina, as an electromagnetic wave, can color be perceived. As Described by Maxwell's Equations The most accurate descriptions we have about the nature of photons are given by Maxwell's equations.
Maxwell's equations mathematically predict how photons move through space. Fundamentally, an electric field undergoing flux will create an orthogonal magnetic field. The flux of the magnetic field then recreates the electric field. The creation and destruction of each corresponding wave allows the wave pair to move through space at the speed of light.
Maxwell's equations correctly describe the nature of individual photons within the framework of quantum dynamics. Creation of Photons Photons can be generated in many different ways. This section will discuss some of the ways photons may be emitted. As photons are electric field propagating through space, the emission of photons requires the movement of charged particles.
Blackbody Radiation As a substance is heated, the atoms within it vibrate at higher energies. These vibrations rapidly change the shape and energies of electron orbitals. Blackbody radiation is what causes light bulbs to glow, and the heat of an object to be felt from a great distance.
The simplification of objects as blackbodies allows indirect temperature calculation of distant objects. Astronomers and kitchen infrared thermometers use this principle every day.
The technical term for this drop in energy is a relaxation. Electrons undergoing this type of emission will produce a very distinctive set of photons based on the available energy levels of their environment. This set of possible photons is the basis for an emission spectrum.
Flourescence Florescence is special case of spontaneous emission. In florescence, the energy of a photon emitted does not match the energy used to excite the electron. An electron will fluoresce when it loses a considerable amount of energy to its surroundings before undergoing a relaxation. Generally florescence is employed in a laboratory setting to visualize the presence of target molecules. UV light is used to excite electrons, which then emit light at visible wavelengths that researchers can see.
Stimulated Emission An excited electron can be artificially caused to relax to a lower energy state by a photon matching the difference between these energy states. The electric field's phase and orientation of the resultant photon, as well as its energy and direction will be identical to that of the incident photon. The light produced by stimulated emission is said to be coherent as it is similar in every way to the photon that caused it. Lasers produce coherent electromagnetic radiation by stimulated emission.
Synchrotrons electron bending Electrons with extremely high kinetic energy, such as those in particle accelerators, will produce high energy photons when their path is altered. This alteration is accomplished by a strong magnetic field.
All free electrons will emit light in this manner, but synchrotron radiation has special practical implications. Synchrotron radiation is currently the best technology available for producing directional x-ray radiation at precise frequencies. Nuclear Decay Certain types of radioactive decay can involve the release of high energy photons.
One such type of decay is a nuclear isomerization. In an isomerization, a nucleus rearranges itself to a more stable configuration and emits a gamma ray. While it is only theorized to occur, proton decay will also emit extremely high energy photons. The Photoelectric Effect Light incident on a metal plate may cause electrons to break loose from the plate surface Fig. This interaction between light and electrons is called the photoelectric effect.
The photoelectric effect provided the first conclusive evidence that beams of light was made of quantized particles. As metals generally have ionization energies of several electron-volts, the photoelectric effect is generally observed using visible light or light of even higher energy. At the time this phenomenon was studied, light was thought to travel in waves.
Einstein later explained this difference by showing that light was comprised of quantized packets of energy called photons.
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His work on the photoelectric effect earned him the Nobel Prize. The photoelectric effect has many practical applications, as current may be generated from a light source.
Generally, the photoelectric effect is used as a component in switches that respond to light. Some examples are nightlights and photomultipliers.