The electron is a subatomic particle, symbol e− or β−, whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron has a mass that is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value, expressed in units of the reduced Planck constant, ħ. Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: they can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy.
Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism, chemistry and thermal conductivity, and they also participate in gravitational, electromagnetic and weak interactions. Since an electron has charge, it has a surrounding electric field, and if that electron is moving relative to an observer, said observer will observe it to generate a magnetic field. Electromagnetic fields produced from other sources will affect the motion of an electron according to the Lorentz force law. Electrons radiate or absorb energy in the form of photons when they are accelerated. Laboratory instruments are capable of trapping individual electrons as well as electron plasma by the use of electromagnetic fields. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications such as tribology or frictional charging, electrolysis, electrochemistry, battery technologies, electronics, welding, cathode ray tubes, photoelectricity, photovoltaic solar panels, electron microscopes, radiation therapy, lasers, gaseous ionization detectors and particle accelerators.
Interactions involving electrons with other subatomic particles are of interest in fields such as chemistry and nuclear physics. The Coulomb force interaction between the positive protons within atomic nuclei and the negative electrons without, allows the composition of the two known as atoms. Ionization or differences in the proportions of negative electrons versus positive nuclei changes the binding energy of an atomic system. The exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding. In 1838, British natural philosopher Richard Laming first hypothesized the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms. Irish physicist George Johnstone Stoney named this charge 'electron' in 1891, and J. J. Thomson and his team of British physicists identified it as a particle in 1897 during the cathode ray tube experiment. Electrons can also participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles. Electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance when cosmic rays enter the atmosphere. The antiparticle of the electron is called the positron; it is identical to the electron except that it carries electrical charge of the opposite sign. When an electron collides with a positron, both particles can be annihilated, producing gamma ray photons.
I understand the electron in the situation to be rapidly accelerated away from the torroid. If this is true, my question is:
Will the electron emmit radiation following the synchrotron formula?
Also, would the radiation travel through the torroid?
Take the case where the electron-beam is oscillating between two parallel metal plates, there will be alternating potential developed between the plates as metal tries to negate all external electric fields.
My query is,
(1) How to calculate the potential developed and possible way to simulate...
Homework Statement
Hello,
I'm asked to show the equivalence of the given Hamiltonian below which describes the interaction between an electron and a nucleus
and the following Hamiltonian
The Attempt at a Solution
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I've simply written down each Hamiltonian as a sum of four tensor...
Let's say we have a transition from state 2p to 1s of an hydrogen atom's electron. The intensity radiated by the electron is given by I = 4/3 ωfi4 e2/c3 |< f | r | i >|2.
If we take the the | 2 1 1 > → | 1 0 0 > transition for example, we must compute the following integral :
< f | r | i > =...
I read somewhere that an electron travels forward in time and a positron travels backwards.And when a photon hits the electron the direction of time for it reverses and it becomes a positron.Does an electron really turn into a positron when hit by a photon? why?
Hi guys! I have a problem with this exercise:
1. Homework Statement
The stars called white dwarfs may have inside them a density in order of 1011 kg m-3. For semplicity, we assume:
these stars are made with non interacting protons and electrons at the same quantity and with uniform density...
Millikan Oil drop experiment.
For my current lab, we are recreating the milian oil drop experiment to measure the charge of an electron. However, we are using 1-micron diameter latex spheres in place of oil drops.
Problem:
I am having difficulty deriving an equation for the speed of the drop...
Homework Statement
I'm taking a module in Solid State Electronics and in the first chapter we went through energy band diagrams, conduction band, valence band, fermi energy level, forbidden gap, etc. Now in the notes it starts to derive some formulae for electron and hole current densities
Jn...
I am wondering about the minimum possible uncertainty (standard deviation) in an electron's position (Δx). How precise can one know the electron's whereabouts without creating other sorts of particles and phenomenons.
I know of the localization energy interpretation of the energy uncertainty...
Homework Statement
An electron is shot towards an infinitely long wire with high current flowing througuh it.
Please, look at my "sketch" in the attachment.
How will its trajectory be affected? What curve will it be?
2. The attempt at a solution
I thought about circular motion, but the fact...
Homework Statement
In a potential box (##L = 1.00pm##) an electron moves at a relativistic speed, meaning it's momentum can't be expressed as ##P = \sqrt{2mE}##.
a) Using the uncertainty principle, show that the speed is indeed relativistic
b) Derive an expression for the allowed energy states...
Homework Statement
I want to derive the following equation. It is the potential energy of an electron inside a nucleus assumed to be a uniformly charged sphere of R.Homework Equations
V'(r) =( -Ze2/4∏ε0R)(3/2 - (1/2)(r/R)^2)
The Attempt at a Solution
I get E = Ze2r/(4∏ε0R3)
But I am having...
I have read the description of electrons as standing waves based on an analogy with a string vibrating at its natural frequencies: thus the different quantum levels are akin to the tones or harmonics of the string, right?
So far, so good, but then I have seen contradictory complementary views...
Homework Statement
So my teacher set us half term homework and one of the questions was state the relative size of a proton a neutron and an electron
Homework Equations
Not sure about equations
The Attempt at a Solution
Im a bit confused because everyone in my class got
Proton: 1
Neutron: 1...
According to quantum mechanics, an electron possesses orbital angular momentum. And we know that orbital angular momentum is possessed by revolving body. Does electron revolve around the nucleus? Please explain. I shall be very much thankful to you.
Ran into a question in my amateur research. Been waaay too long since college physics, and I've exhausted searches. This is the theoretical question:
Assume a non-conducting, infinite plane charged to +10 kV. An electron leaves perpendicular to the surface with an energy of 10 keV. How far...
I am in the midst of a discussion with someone who feels very confident that an electron is always and forever a point particle and never a wave; any wave-like behavior that is observed must be attributed to a pilot wave that guides the path of the electron.
I have sought to argue that this...
Homework Statement
Write the electron configuration for Cd 2+.
Homework EquationsThe Attempt at a Solution
[Kr] 4d10
Whenever we remove electrons do we always remove it from the s orbital in that period. So for cadium ion we remove 5s2 correct? But let's say it's Mn 2+ would we remove the...
Homework Statement
In a measurement of the electron charge by Millikan's method, a potential difference of 1.5 kV can be applied between horizontal parallel metal plates 12 mm apart. With the field switched off, a drop of oil of mass 10-14 kg is observed to fall with constant velocity 400 μm...
I've been reading up on electron diffraction for electron microscopy, and I have been trying to understand the proof for the wavelength of an electron in a tunneling electron microscope. The proof I have been trying to emulate begins as follows:
It then says that I must account for...
I have been researching wave/particle duality, and I have trouble comprehending how electron microscopy actually exploits wave/particle duality to operate.
From Wikipedia, "
Wave–particle duality is exploited in electron microscopy, where the small wavelengths associated with the electron can...
We have this situation
an electron comes flying in electric field between two capacitor plates. Let's say that voltage is 12V and distance between plates is 1m. Electric field E=U/d=12V/m. Plates are connected to the battery just initially. The battery is later disconnected.
If electron comes...
Homework Statement , 2. Homework Equations , 3. The Attempt at a Solution :
[/B]
If an electron and photon have the same energy, the electron will have a shorter wavelength, and a larger momentum. The shorter wavelength makes it useful for electron microscopes, outperforming optical microscopes...
Hello,
I am learning about electron spin resonance and I just want to see if my understanding is correct. From what I gathered, if you place a paramagnetic material in a magnetic field, the electron energy levels split, and when you then apply EM radiation (generally microwave frequency) that...
I am trying to calculate what we'd expect the uncertainty in energy would be for an electron in a hydrogen atom where it was confined to its usual radius (120 pm) versus if we confined it to the width of a proton (.88 fm) to try and make an argument about why the electron does not fall into the...
Homework Statement
Homework Equations
none
The Attempt at a Solution
Here is my attempted answer, can someone please tell me if I did this correctly, thank you :)
22.
Final electron receptor molecule involved in aerobic respiration:
* the electron transport chain relies on oxygen to keep...
Homework Statement
Why is the EA of Neon endothermic even though it has a high Z eff?
Basically, what makes a full valence shell so stable?
The attempt at a solution
I know it has to do with shielding, core e-, and valence e-. But I don't know how to word it.
A few quick questions I'd like cleared up:1) Alkali metals are said to have a really low threshold energy, enough for visible light to cause the photoelectric effect. Does this mean if I aim a flashlight (turned on) at a piece of sodium, I could ionise it? Simply flashing a light over a piece of...
A photon has a spin of 1, while an electron is 1/2. I've heard it said that the electron needs to spin 720 degrees to complete a full cycle. Is there any proof that the electron is spinning 720 degrees and not just spinning 360 degrees, but at a lower harmonic of the photon-- 1/2 the photon's...
Homework Statement
The radial wavefunction for ##3d_{z^2}## orbital is
$$R=N\sigma^2e^{-\frac{\sigma}{3}}(3\cos^2\theta-1)$$
$$\sigma=\frac{r}{a_0}$$
Find r and θ for which the probabiity of finding the electron is maximum
Homework Equations
None
The Attempt at a Solution
##R^2## gives the...
Homework Statement .
An atom at rest can undergo radioactive decay, ejecting an electron at a maximum speed of 0.5c. If the atom in a particle accelerator is observed to produce an electron traveling at 0.75c, at least how
fast must the atom itself have been moving?
Homework Equations
u0 x...
This is a multiple choice question that, after one incorrect attempt, I got correct; however, I want to actually understand what the explanation means. I'm hoping someone here can help.
Homework Statement
Two electrons, each with mass m and charge q, are released from positions very far from...
My very amateur knowledge of the nature of matter is that particles like electrons are local disturbances in a universe-wide field, like the electron field and that a field is a set of values for some quantity, one for each position in space.
What I'm wondering is: What is that quantity in the...
Consider two atoms of platinum, A and B, in a sample of platinum. Atom A lives deep within the sample, and atom B lives at the tip of a sharp protuberance at the surface. My understanding is that electrons in the sample will accumulate within a surface defect such as the tip of a sharp needle...
I am trying to express some physical constants in natural units of ##c=1## and ##\hbar=1##.
Let's start with the electron mass. In SI units, the electron mass is ##0.511 \text{MeV}/c^{2}##. I understand that in natural units, the electron mass is simply ##0.511\ \text{MeV}##. Now, is the...
Hi,
I am looking for the reasons for the generation of heat developed in a material due to electron bombardment. Searching in the internet gives me only the estimations of the heat developed, but not the physical reasons for the heat development. Appreciate if I am provided any insight into the...
Homework Statement
An electron is released from rest in a weak electric field given by = -2.70 10-10 N/C [PLAIN]http://www.webassign.net/images/lowercase/jhatbold.svg. After the electron has traveled a vertical distance of 1.4µm, what is its speed? (Do not neglect the gravitational force on...
Hallo everyone,
I have a question about X-Ray shielding in a scanning electron microscope and I hope you can help me!
The topic is that when electrons hit the specimen, characteristic radiation up to 10keV is generated. This radiation is blocked/decelerated my the surrounding tower and chamber...
Homework Statement
Hi everybody! I'm unsure how to tackle the following problem, hopefully some of you can give me some hints on how to do so. :)
How big is the force acting on an anode by an electron current of strength ##I=0.3##A if the electrons are accelerated with a voltage ##U=300##V...
Homework Statement
On which orbit of hydrogen atom an electron has the speed of 734 km/s?
Homework Equations
Bohr's second postulate: mvr=nh,m=9.109\cdot 10^{-31}kg,v=734 km/s,h=6.626\cdot 10^{-34} m^{2}kg/s
The Attempt at a Solution
By using the second Bohr's postulate, we get 6686.006\cdot...
I came across this and i was fascinated, i hopefully would like to attempt to build a recreation of this but i have no idra what they used to make the accelerator work on this size.
Any help...
I am trying to make a connection between the two in terms of the electron configuration for an atom relative to the octet rule for Lewis Dot diagrams. Maybe I just don't understand what the electron configuration represents. Why is it that Lewis Dot diagrams utilize 8 valence electrons as a full...
If the amplitude of gravitational waves, frequency of gravitational waves and the vector potential of magnetic field in surrounding of such waves are known then what would be the easiest way to calculate resultant acceleration of electrons?
My above question is based on the various researches...
I have seen some sites say that it doesn't and other says the opposite. So let's see
Source of the pic: Chemguide
Lets look at the hydrogen (Oxidation) half cell. If we assume that it contributes x volts until the electron reachs the copper, then no matter how big is the distance the voltage...