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.
Electron can move from lower energy level to higher energy level when it absorbs energy equal to the difference between the energy levels based on equation: ##hf = \Delta E##
If the incident photon has lower energy compared to ##\Delta E##, then electron won't move to higher energy level. But...
This is dumb question, so please bear with me.
In the double-slit experiment where they fire a single electron at time, as you can see the electron gun fires a single electron.
Now the electron travels as a wave.
Now my question is, why doesn't the wave collapse when the wave encounters...
What is the difference between electron correlation and electron exchange?
Which of them is due to the spin of electrons and which is due to charge of electrons?
We usually think about atomic orbital as wave(function), but it was created from e.g. electron and proton approaching ~10^-10m (or much more for Rydberg atoms), and electron has associated electric field.
This wavefunction also describes probability distribution for finding electron (confirmed...
Hi,
Is there anybody who knows about this subject and can guide kindly?
Regards,
In electron beam lithography, there is an optimum aperture angle to obtain a minimum beam size:
a) Determine this angle considering only the influence of the source and spherical aberrations.
b) What is the...
In the traditional single electron duel slit experiment, I assume a cathode emits electrons in an unfocused direction spreading across the dual slits like a flashlight beam, but one electron at a time. Electrons however can be finely focused and controlled using magnetic or electric fields...
Hi,
If we multiply $En=-\frac{2\pi^2me^4Z^2}{ n^2h^2} $by $\frac{1}{(4\pi\epsilon_0)^2},$ it is the formula of electron energy in nth Bohr’s orbit. Why we should multiply it by $\frac{1}{ (4\pi\epsilon_0)^2}$ a Coulomb's constant in electrostatic force?
Where m=mass of electron, e= charge...
Hi,
I was wondering if anybody knows why the plate in an electron gun is tilted with respect to the electron path? Or has any resources that I could read to better understand? Thanks.
a) E = s / E0 so s is 4.87E-9
b) The electron will be projected at up angle since its charge is negative ( not sure if there's another reason behind it)
c)
Initial speed:
V0 = 5 * 10^6 * cos(theta) + 5 * 10^6 * sin(theta)The force suffered by the electron is:
Fy = q*Ey
Fy = -1.602*10^19 *...
When solving the Schrodinger equation by separation of variables to atom with one electron and in the spherical coordinates, we get $$\Psi = \Theta(\theta)\phi(\varphi)R(r)$$
Specifically, $$\phi = e^{im\rho }$$
The question is, why we adopt this particular solution, in general, we have this...
Can you compare the energy loss of electrons and protons due to the radiation they emit? In fact, I want to know which of the two loses more energy when it emits radiation.
Ve=0m/s
Vp= 0m/s
Qe/Qp= 1.60E-19
Me=9.11E-31
Mp-1.67E-27
Ive pretty much gathered all of the equations I think I need to solve the problem. I just am stuck. The last step I realize that the forces would be equal to each other so I have mp x ap = me x ae but then when I try to solve for the...
1. The 4th line from the left, being the aqua blue line, corresponds to a wavelength of 486 nm, as blue light has a wavelength in the range 450-495 nm.
2. This is where I am having the most difficulty, I have tried to answer the question comprehensively but I am not satisfied with my answer.
In...
I don't really understand the question. I don't understand the wording. We know the plate has a thickness L = 0.50cm. If the charge is coming from the battery wouldn't the electrons have to move the entire distance to reach the face of the plate? Because they have to move all the way from the...
If τ is the relaxation time, τ means, on average the time between two collisions for an electron moving under a constant electric field inside a metal. Now according to the assumptions of drude model, the electron acquires an additional velocity of \frac{-eEt}{m}where t is the time elapsed since...
Mass of an electron = 9.1*10^-31
Well, to find the maximum kinetic energy of the electron use E=hf, E=hc/λ=6.63*10^-34*3*10^8/1.5 *10^-7
E=1.326 *10^-18 J
1/2m v^2 max=E
Rearrange in terms of v:
v=√2E/m
v=√2*1.326 *10^-18/ *9.1*10^-31
v=1707127... ~ 171000 ms^-1
Where have I gone wrong here?
Hi,
I was reading the following Wikipedia article and couldn't make sense of few points. I'd appreciate it if you could help me with it.
Source: https://en.wikipedia.org/wiki/Electromagnetic_mass#Rest_mass_and_energy
Question 1:
What is this "electrostatic energy ##E_{em}##"? Is it some kind...
A single electron sitting in a void has an electric field that spreads out evenly in all directions as far as there is open empty space to allow it, is this roughly a correct statement?
Let's say we now introduce a singe proton into the void, 100 miles from the electron - it will also have an...
I what to know what is electron scattering in Brillouin zone boundary?
What exactly happen for electron in Brillouin zone boundary; what happen for it in real space and what happen for it in reciprocal space?
And is electron scattering from a Brillouin zone boundary could be a source for...
Bohr's hydrogen atom model is outdated facing Schrodinger's wave equation. Now that wave mechanics doesn't use a concept of orbit for the electron in hydrogen atom. But can we suppose the electron is still circling around the atom core, not necessarily in circles or ellipses, but in chaos like a...
So from what I understand the position of an electron at any given time is based on a probability model. My question is how does gravity play a role in this model?
Can we say the position of the electron is truly random? What if this "randomness" is caused gravitational forces pulling it in...
We know the RT-PCR test method currently employed to detect SARS-CoV2 viruses from the sample is not 100% foolproof in detection.
If the current electron microscopy can reach a resolution of up to 50pm, why not use this time-tested technology in the detection of this virus?
Are there any...
After many months what comes out of the mouth and nose of someone infected with Covid 19 has not been directly observed.
A single virus particle of Covid 19 is about 120 nanometers in diameter. This means that to see the virus, visible light wavelengths of 400 nm to 700 nm are too long to...
The Dirac equation for an electron in the presence of an electromagnetic 4-potential ##A_\mu##, where ##\hbar=c=1##, is given by
$$\gamma^\mu\big(i\partial_\mu-eA_\mu\big)\psi-m_e\psi=0.\tag{1}$$
I assume the Weyl basis so that
$$\psi=\begin{pmatrix}\psi_L\\\psi_R\end{pmatrix}\hbox{ and...
Hi folks,
My understanding of the Compton Effect is that maximum energy transfer to the electron takes place when the photon scattering angle is 180 degrees.
For the following please reference Evans "The Atomic Nucleus" ...
When I see explanations for quantum tunneling, the discussion is around the probability of an electron manifesting itself before the potential barrier, and after the potential barrier. However, looking at the curves draw, there is a non-zero probability (the evanescent part of the wave) inside...
I came across a problem that seemed fairly interesting; it asks what would be the trajectory of an electron released from rest inside a Faraday cage (which is itself within a uniform gravitational field ##\vec{g} = -g\hat{y}##). I didn't quite understand their explanation.
They say that...
Neutrinos oscillate at different flavors while propagating in space and this is due to their mass.Any particle being massless cannot oscillate between different flavors while leptons with the mass of the electron and above are very unlikely to change their flavor. Will we able to detect a change...
Is it possible for an electron in the 1s orbital of an hydrogen atom to be indefinitely far from the nucleus in a given instant?
From the Schrodinger equation we can see that the radial probability is NEVER zero, so it would be possible to see an electron in the moon, for example.
But if I...
Hello! I read in several (more accessible) papers (e.g. https://www.sciencedirect.com/science/article/pii/S1049250X0860110X) that the EDM of the electron is so small, because one needs to go to 4 loops or higher to get a non-zero effect. It seems like at 1 and 2 loops there are some symmetry...
I've got a quick question on the relationship between the kinetic energy of individual electrons and the total electrical energy they create.
I have a radioisotope - a beta emitter - which produces electrons with around 1 MeV (1.60218×10-13 Joules / 4.45049×10-17 Watt-hours) of energy.
I keep...
In the book" The Quantum Theory of Radiation", Heitler derived the transverse self-energy of the electron(Chapter III, Section18, Eq.(23))
$$\frac{{{e^2}}}{{\pi m}}\int_{\text{0}}^\infty {kdk} $$
which is the energy of the electron under the action of the vacuum fluctuation of the
radiation...
Modern batteries use double-sided anode and cathodes for greater energy density. Series wiring of batteries is typically accomplished by connecting the anode of one cell to the cathode of another. However, can series be accomplished by stacking double-sided anode and cathode alternatingly with...
It will try to produce a neutral atom but it depends on the amount of energy that electron is shot at the atom, if it is great enough energy for ionization it will produce cation, If it is not enough for ionization it will make a neutral atom or anion, I think.
I think that an electron adds up in the valance shell of an atom because an atom tends to achieve the nearest noble gas configuration. But I don't understand how and why electron enters the valance shell. Energy is released when an electron adds up in the valance shell. But why is energy...
Hi, I've been reading out of curiosity about linear accelerators to get a general ideal of the principles behind them. My main concern is that, as far as I could tell, there are two different types (I'm sure there are more than two, but I want to keep things simple) of Linear Accelerators...
Hello, this problem is causing headaches, it would be very helpful if you could tell me if you know of a book where you can solve it. Maybe my English is lousy because I use a translator. Thank you very much.
hello
Witch of these are certain sentences?
a-\dfrac{e}{m_e}>\dfrac{H^{-}}{m_{H^{-}}}\cdot{1000}
b-\dfrac{e}{m_e}>\dfrac{H^{+}}{m_{H^{+}}}\cdot{1000}
The first accurate measurement of e/m was made by english physicist J.J. Thomson in 1897, who demostrated that the quotient charge-mass of the...
Let's suppose a solar electron moving directly towards Earth's equator at a high speed. This electron meets Earth's magnetic field, which points to the north, at a distance ten times the Earth's radius, where magnetic field is almost uniform. Which will be the direction this electron describes...
I've written out the half reaction
8e- + 9H+ + SO42- = HS- + 4H2O
and I know the logK = 4.25 (that's the constant mentioned in the prompt)
I've written out the equilibrium statement of 10^4.25 = ([x^1/8]*[H2O^1/2])/([10x^1/8]*[e-]*[(10^-8.2)^9/8]
However, from there, it seems like I have two...
So I'm reading up on this device and what I get is that in all electron guns once the electrons are emitted they would tend to repel one another so in order to make the beam focused instead of spread out across, one uses magnetic fields in the electron microscope,
So after the focused beam hits...
On p. 246 in the Peskin QFT textbook, below is stated
where Z3 is defined as the residue of the q2 = 0 pole, explicitly as
$$Z_3=\frac{1}{1-\Pi(0)}$$
and e is the bare charge.
In advance, the exact photon two point function is calculated as
$$\frac{-ig_{\mu\nu}}{q^2(1-\Pi(q^2))}$$
Though...
I honestly just have no idea where to start on parts c and b. I tried 1.1*10^-12 N x 3218 m for part a, which was right. But I'm lost on b and c. I'm also wondering if we have to include a gamma factor in any of this, but I'm unsure how or where. Any help would be amazing.
Does the negative terminal of a battery have a negative charge due to having a surplus of electrons? If so, then why do the surplus electrons from the negative terminal of the battery not discharge to the human body or Earth (which have a neutral charge) when touched?...thereby causing the...
Does anyone know theory about how the perturbation lines are for 1s hydrogen electron? By perturbation I mean the perturbation that is caused by moving an electron so that the E-field lines it emits becomes dragged.
by perturbation I mean for example dragging a charge as described below
Above...