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 explain it better. If we bring an electron from higher to lower energy level, the energy gap will be emitted as electromagnetic wave, because of the conservation of energy. When the same situation applies for a physical body, for example letting if falling down from some height, what does it...
I am in grade 9 in the IB curriculum and next year I have to do something called a "Personal Project" where I have to make something and explain why I did it. I would like to recreate the double slit experiment. However, I have to obtain a electron gun and they are quite hard to come across. So...
Homework Statement
If possible could someone have a look at my working for this problem, I am not sure if I have carried out part b) correctly. I have done all three problem and carried through my solution to b) just to see if it did simplify out, which it didn’t which make me think I may have...
If an electron starts from rest 85.0 cm from a negative fixed source charge of -0.135 micro coulombs we use the equation ke final - ke intial + pe final - pe intial. In solving you use ke = pe which appears to cancel out the inital kinetic and potential energy but how can the initial potential...
My unreliable memory is that although Schrödinger's equation treats the interaction between an electron and the nucleus as unquantised, it is more generally thought to be mediated by an exchange of quanta between electron and nucleus. I want to check on this and get a better understanding. Can...
I am an undergrad physics major in my final semester currently taking Intro to Thermodynamics. As a final project, each student must choose a topic related to thermodynamics that is more advanced than what is covered in the curriculum and write a paper and present our findings to the class on...
Homework Statement
An electron is fired at 4.0 x 106 m/s horizontally between the parallel plates, as shown, starting at the negative plate. The electron deflects downwards and strikes the bottom plate. The magnitude of the electric field between the plates is 4.0 x 102 N/C. The separation of...
Homework Statement
A magnetic field of 0.0200 T [up] is created in a region.a) Find the initial magnetic force on an electron initially moving at 5.00 x106 m/s [N] in the field.b) What is the radius of the circular path? Make a sketch showing the path of the electron.
Homework Equations...
Homework Statement
Consider a one-dimensional metal wire with one free electron per atom and an atomic spacing of ##d##. Calculate the Fermi temperature.
Homework Equations
Energy of a particle in a box of length ##L##: ##E_n = \frac{\pi^2 \hbar^2}{2 m L^2} n^2##
1D density of states...
Hi everyone, I have been studying the physics of solar cells for a long time. The only thing that I can not completely understand is the physical operation of solar cell based on band diagram.
Can anyone briefly explain the movements of carriers from one electrode to the another based on band...
Hi, I wonder is it possible to trap electrons in vacuum using acoustic waves as it is possible to trap them using electromagnetic waves?
imagine a vacuum tank and electrons injected say from a thermionic emission (electron gun) and having one or two transducers set apart to produce satnding...
Do protons' inherent gyroscopic nature produce progressive ripples in the electromagnetic field? If so, then is there an ensemble of transverse electromagnetic undulations arising from the proton's angular momentum that contribute to electronic orbital energy in, say, a hydrogen atom? If these...
Homework Statement
How much kinetic energy is in electron volts?
Homework Equations
Kinetic energy = 1/2 mv2
1 electron volt = 1.6 x 10-19 J
The Attempt at a Solution
[/B]
It's a bit unclear to me what the question is asking, since no context at all is given. It's one of the questions in...
I have been trying to understand some of the basic differences in the fundamental nature of leptons and quarks. One article on this issue compares leptons and quarks as "oranges vs apples" to which I basically agree except for one aspect. How can the charges of the quarks be 1/3 or 2/3 the...
I'm quite new to quantum mechanics. I have a question, I'm coding a small game with my friends and I do understand the orbitals and I've even written a function in java to simulate the probabilities of ONE of those diagrams, but I do not know my scale just yet, can anyone tell me the width of...
Homework Statement
Electron configuration of Fe(2+)
Homework Equations
spdf configuration
The Attempt at a Solution
1s2 2s2 2p6 3s2 3p6 3d3 4s2
But from (https://www.thestudentroom.co.uk/showthread.php?t=1232420),
it says 1s2 2s2 2p6 3s2 3p6 3d6.
isn't electrons fill up 4s shell first...
Homework Statement
After beta- decay electron and antineutrino comes out, electron is moving along z axis and it is moving with velocity v. It's spinor is
## \mid\chi\rangle=A\left(\frac{\sqrt{1+\frac{v}{c}}\sin\frac{\theta}{2}}{\sqrt{1-\frac{v}{c}}\cos\frac{\theta}{2}}\right) ## where A is...
In an old fashioned electron microscope (the type I was meant to understand at university 50 years ago), are the electrons coherent, or do we just consider an electron interfering with itself? If they are coherent, how are they made coherent?
I have learned about the principles of quantum mechanics from two sources. The first is a book called quantum mechanics concepts and applications. The second is prof. Allan Addams lectures in MIT. But they have different opinions about what happens to the interference pattern of electrons when...
For a proton to capture an electron to form a neutron and a neutrino (assumed massless), the
electron must have some minimum energy. For such an electron,how can the de-Broglie wavelength be found out?
Homework Statement
Low-energy electron diffraction (LEED) experiments are carried on to study a deposition of argon (Ar) and
xenon (Xe) on the surface of a graphite single crystal. In the regime of vapor pressure considered, 75% of Ar
and 25% of Xe are adsorbed on the (hexagonal) crystalline...
Images aren't embedding properly, so forgive the urls.
This is the question I am attempting to answer:
https://imgur.com/a/mEcAl
and this is the start of my answer:
https://imgur.com/a/8MoDi
so.. I wasn't expecting just to get the coulomb potential at the end. This is supposed to be the...
If we have a MIM device of Ti/Nb2O5/Ti at room temperature (300K), with a measured barrier height(s) of 0.0eV, the insulator thickness is say 2nm, and let's call the electron affinity of Nb2O5 4eV, and the Work function of Ti 4eV (for the sake of a simplified question), what is the average /...
Homework Statement
Which, of an electron and a proton (of a few Mev), is more likely to penetrate further into matter if they both have:
a) The same energy
b) The same speed
Homework Equations
Bethe-Bloch formula.
Total stopping power = collision loss + radiation loss
(de/dx)t = (de/dx)c +...
Since we know that when an electron goes from the ground state (hydrogen) n=1 to n=3 for example, we have
ΔE = E3 - E1
by manipulating the equation we get Rydberg's formula
1/λ= R (1/ni2 - 1/nf2) (where R is Rydberg's constant)
My question here, if the electron goes from higher energy state...
Hi at everyone, why on wiki there is written:
" According to modern understanding, the electron is a point particle with a point charge and no spatial extent. Attempts to model the electron as a non-point particle are considered ill-conceived and counter-pedagogic "
I don't understand this...
Homework Statement
Homework Equations
E = γmc2
p = γmv
K = E - mc2
E2 = c2p2 + m2c4
The Attempt at a Solution
I have completed most of this question, but I am struggling to get the required result to the final part of the question.[/B]
I have been studying Optical Isomerism recently, and I have got one question, answer to which was not in the books that I have.
I have understood what the phenomenon is, and that, how one can determine whether the plane of polarised light is rotated, and how to tell from the structure whether...
What is the value of optical effective electron mass for tin metal (white tin)? What is the value of mean free path for electron of tin metal? At least give me some websites or papers where I can find it?
In the calculation of R=σ(e+e-→hadrons)/σ(e+e-→μ+μ-) from BaBar experimental data at a center of mass energy of √s≈10 GeV i obtain R=5. Theoretically I should get a value of R=10/3. I know it has something to do with the resonances of ϒ mesons shown in the plot attached, but I don't know how to...
Homework Statement
When an electron in a hydrogen atom makes a transiton between two levels with prinicipal quantum numbers n1 and n2, light is emitted with wavelength of 658.1 nm. If we assume that the energy levels of the atom are in agreement with the Bohr model, what are n1 and n2...
Hello, I was trying to make a simple model of an electron tunneling through several potential barriers. The electron will flow through a conductor to a heterojunction of possibly semiconductor/oxide layers. I assume the electron is coming as a plane wave from the left with some energy E. We know...
Homework Statement
What is the escape speed of an electron launched from the surface of a 1.0-cm-diameter glass sphere that has been charged to 10nC?
Homework Equations
Given:
d= 1.0cm
r= 0.05cm= 0.0005m
q1 = 10nC = 10 x 10-9 (sphere)
q2 = -1.6 x 10-19 (electron)
Equation:
U = (kq1q2)/r
KE=...
Homework Statement
A proton is released from rest at the positive plate of a parallel plate capacitor. It crosses the capacitor and reaches the negative plate with a speed of 50,000 m/s. What will be the final speed of an electron released from rest at the negative plate?
Homework Equations...
I was studying the spin-orbit interaction and the Zeeman effect, and came across the concept of optically active electrons.
Initially I got the idea that an optically active electron is any unpaired electron. But then, while trying to understand the Zeeman effect in a Cadmium atom, for which...
Homework Statement
A proton beam is going from north to south and an electron beam is going from south to north, so in which direction is the electron beam deflected
Homework EquationsThe Attempt at a Solution . [/B]
I thought an electron...
Hi Guys,
I have attempted the question below. Please have a look at my work and let me know if everything looks fine. Any feedback would be great.
1. Homework Statement
Homework Equations
F = qv/d
a = F/m
t = d/v
qv = 1/2mv^2
x = vt + 1/2 at^2
The Attempt at a Solution
Homework Statement
An electron acquires 3.16*10^-16 J of kinetic energy when it is accelerated by an electric field from plate A to plate B. What is the potential difference between the plates, and which plate is at the higher potential.
Homework Equations
w =Δv * q
The Attempt at a Solution...
Homework Statement
A single electron atom has the outer electron in a 4f1 excited state. Write down the orbital and spin angular momentum quantum numbers and the associated magnetic quantum numbers for this state.
Homework Equations
I don't think there is any relevant equations. I think it...
Homework Statement
Homework Equations
E=hc/lamda
The Attempt at a Solution
I can get the amount of energy incident on the surface (3%of Intensity×Area)
What will be the energy required to make 1 electron escape?
(4.5eV+hc/250nm )?
Then I divide total energy by energy to make 1 electron...
Homework Statement
How many free electrons are there in the CB? Diamond has a bandgap of ##5.5##eV.Assume the material is at room temperature and that there are ##2 \times 10^{22}## cm##^{-3}## electrons in the material. What does this mean for their use in semiconductor devices?
Homework...
Homework Statement
How to calculate the probability of finding an 1s electron within 1 picometer cubic region located 50pm from the nucleus.
Homework Equations
The probability of an 1s electron within a spherical volume of radius 'a' from nucleus can be find using the expression...