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.
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...
Homework Statement
In a certain region of space, there is a uniform electric field, E = 4.28 x 104 V/m directed due east, and a uniform magnetic field B = 0.071 T, also directed due east. What is the magnitude of the electromagnetic force on an electron moving due south with a velocity of 3.09...
Homework Statement
A 191Os nucleus decays via β- emission to an excited state of 191Ir at 171 keV. What is the maximum kinetic energy of the electron on the β spectrum?
a) 0.134 MeV
b) 0.143 MeV
c) 0.171 MeV
d) 1.859 MeV
Homework Equations
191 Os = 190.960928u
191 Ir = 190.960591u...
The electron gyromagnetic ratio of 1.0011596522 is computed using perturbation method and Feynman diagrams that is said to produce a value to better than one part in 10^10, or about three parts in 100 billion. Does the nonperturbative lattice QFT also able to compute it? What is the counterpart...
Hello,
I was wondering if it would be possible to eject chemical compounds from a sample, say like a biological tissue, using an electron beam. I know that electron scattering is one product of electron-specimen interaction, and that's the principle behind electron microscopy, but I'm more...
Homework Statement
(a) What voltage will accelerate electrons to a speed of ##6.00 \times 10^{-7} m/s## ? (b) Find the radius of curvature of the path of a proton accelerated through this potential in a 0.500-T field and compare this with the radius of curvature of an electron accelerated...
Hi, I need to calculate the current in a 400nm piece of graphene. Can some one help me please? I found online that graphene has electron mobility of 200,000 cm^2/( V s). My best attempt is as follows. Using the equation vd = uE where E is the magnitude of the electric field applied to a...
Homework Statement
Here's the pic of the problem and my work
The Attempt at a Solution
I'm not sure how I'm suppose to calculate the energy change? Did i do it correctly in the picture?
For number 9, I just added IE1 and IE2 and subtracted EA1 to get a total of 3200.3. This means that the...
Hello,
Chromatin in the living cell is divided into Heterochromatin and Euchromatin. My book states that the Heterochromatin, when examined by the electronic microscope, is electron dense, and the Euchromatin is electron-lucent.
I don't understand any of the concepts in bold.
And I would...
Homework Statement
An electron is fired from x = 0 with an unknown V0 at 45 degs to the horizontal between two parallel plates separated by 2 cm. Electric field is 103 j N/C. Find:
a) The max value of V0 so that the electrons don’t hit the upper plate
3.75 * 106 m/sHomework Equations
If you...
If two electrons are far apart, the antisymmetrization part in the probability amplitude for position is negligible and they behave as classical particles, thus we don't need to consider antisymmetrization. My question is why is this also true when we have a large number of electrons, say...
Homework Statement
For the hydrogen atom in the first excited state, find the probability of finding the electron in a classically forbidden region.
Homework Equations
E1 = -Z2μe'4/2n2ħ2
ψ200 =
∫ψ(r)2dr from the limit to ∞
The Attempt at a Solution
https://imgur.com/a/fWIMq
I feel like this...
Homework Statement
An electron enters a region between two large parallel plates made of aluminum separated by a distance of 2.0 cm and kept at a potential difference of 200 V. The electron enters through a small hole in the negative plate and moves toward the positive plate. At the time the...
When radiation of frequency less than threshold frequency falls on a surface of metal, it gives energy to the electron and at a instant later another radiation of same frequency strikes the same electron, if the energy of two photon equals or is greater than the work function of the electron in...
Hi, I just have a few questions I'm struggling to find straightforward answers to online.
The 4 quantum numbers of an electron in an atom describe the energy level, shape and suborbital of the orbital, and the fourth assigns a value to the electron's spin. Question 1) why is it in lone atoms...
Imagine attaching electrodes to a complex sample, e.g. a semi-conductor or a single chemical molecule, leading to some electric current.
Can we decompose this electron flow into local flows? - like locally attaching amperometer and counting what fraction of electrons flow directly between given...
If you were sending microwaves one direction to ionize a gas, would you be able to pull or separate the atoms from these directionalized electrons? Say you had a magnetic coil with a strong e field pulling the atoms one way while the microwaves were trying to push the electrons the other way-is...
Hi! In school I was thaught that magnet doesn't have anything to do with the motion of electrons, but then when you see the way electromagnetic induction work, it seems like the magnet move the electrons somehow. How is that possible and can we control the movement? Thanks a lot and sorry for my...
The quantum physicists claim, that an electron has been 'smeared out' in the space around the nucleus.
So it seems an electron in the atom is present everywhere at once.
Is the next interpretation acceptable?
The electron moves with many km/s in an extremely small space.
In photography it...
I'm studying for a qualifying exam and I see something very strange in the answer key to one of the problems from a past qualifying exam. It appears the sigma^2 for a two electron system has eigenvalues according to the picture below of 4s(s+1) while from my understand of Sakurai it should have...
Homework Statement
Hi guys, I'm currently writing an extended essay in Physics looking at the effect of percentage composition of Sn has on the electrical resistivity of SnPb Solder. I've noticed that Sn is listed as being a better conductor than Pb, despite trends of periodicity and have been...
I was having a casual conversation with my uncle the other day and he basically told me that electron is a field. Essentially he claimed that there is an electron field that encompasses the whole universe (like the Higgs field) and what we think of as an "electron particle" is just a fixed point...
1)Is the wave function of the electron perpendicular to the motion of electron in straight line in the similar fashion as that of the photons.?
2) And what is the origin of this wave function?
3) can someone give me the details about the electron in double slit experiment (and mainly a theory...
I was trying to help (elsewhere) a student with some QM related problem and I realized something. When discussing QM we underline the fact that electron doesn't behave as a particle, it behaves as a wave. Yet when we explain wave function we say something like "square of the wave function is a...
Homework Statement
What is the force on an electron with a velocity v = (2i – 3j) Mms-1 in a magnetic field B = (0.8i +
0.6j – 0.4k) T
Homework Equations
F=qvBsinθ
The Attempt at a Solution
using cross product I got: (1.92i + 1.28j + 5.77k)10^-13 N which is the listed correct answer.
My...
Hello!
How do I find how much energy does electron radiate during one revolution if the energy radiation rate is given by Larmor Formula: dE /dt = [(− 2/3)* e2* a2]/ c3. Should I use the chain rule? At the moment I only want a hint how to solve this.
With best regards
I have this brain worm and it's been bugging me for ages. I don't know enough about anything to be able to answer this but when I heard a theory that an electron can be in 2 places at once but then appears to be in a specific location when observed I started wondering how this could be possible...