Electrons Definition and 998 Threads

In the double-slit experiment, without which-path information available, the diffraction pattern is usually shown as an even function with respect to the displacement from the midpoint of the slits: something like sin ay / y. (This is the case in Feynman's lectures, and many others.) The...

Homework Statement Two metal plates, PQ AND RS are separated by a distance of 15 mm. PQ maintained at potential of +100V relative to RS. Beam of electrons of different kinetic energies directed a slit ,on plate PQ, at angle of 60 degrees to plate. To find the K.E of electrons that 'just'...

Hi All, Protons repel each other and in order to make them collide in the LHC huge amounts of energy have to be put in place, my question is; if we launch a beam of electrons transversal to the beam of protons and right in the collision point of the protons, would not this increase the energy...

Do ions have a measurably different rate then their neutral counterpart or does the rate of radioactive decay and electrons have no correlation? Also, when a source states an elements half life is that the same for all of its isotopes?

Hi. I would like to know if the results of the observations of electrons passing through double slits needs to be observed by a person for the electrons to act like theyve been observed? Or, is the equipments observation of the electron is enough for it to act like its been observed...

I was just reading R.Feynman's Lectures on physics Vol I and I came across this discussion in which he says that magnetic field results from an electric field i.e relative motion of electrons and so on. Further, he says that the electomagnetic spectrum consists of light waves... The whole...

Hi. I'm currently working through Griffith's Introduction to QM, and have gotten to the section on the periodic table. I'll explain my understanding a little bit... Before this he's been looking at the Hamiltonian for helium: H = \left[ \frac{- \hbar ^2}{2m}\nabla _1 ^2 - \frac{1}{4 \pi...

I am wondering about the barrier in PN junction diode.Due to diffusion negative ions are formed on the P side and Positive ions are formed on the N side of the diode.both opposite sides exert force of attraction and so a line of positive ions and negative ions align along the junction. The...

Do electrons flow in a "circuit" in a CRT? When they hit the phosphor coating on the screen, does the final anode complete the circuit and allow current to flow back to the circuitry or does the anode only serve to accelerate the electrons which then "accumulate" by combining with the phosphors...

Homework Statement So i know the light colour, wavelength, cutoff potential and frequencies. I am trying to find the maximum kinetic energy of the ejected electrons(J or eV) heres the first set of numbers for the colour of yellow: wavelength 578nm(5.78 x 10 to the -7metres). cutoff...

attraction -- why do electrons and protons attract each other? Hi, why does electrons and protons attract each others? This happen with other particles too (photons, neutrino etc..) ? thanks

If bubble chamber tracks are formed by charged particles leaving a trail of ions as they pass through, by knocking electrons out of atoms, then why aren't there spirals of electrons along the whole track? Also, are the straight lines in bubble chamber photographs actually curves of a very...

Hi all, First of all, sorry if this is a dumb question but I just wanted to make sure. Imagine the body of an electron microscope and the focusing coils on it. I know that due to the generated magnetic fields, the electrons tend to modify its distance to the central axis in a helix-like...

Is there an equation to find out the velocity of electrons and protons in a loop of plasma when a current is induced through it?Is the velocity just equal in magnitude and opposite in direction or is it opposite in direction and the velocity dependent on mass of the particles?(implying that an...

I am back with another doubt and i am in 11th grade now Can someone please explain what the electron really is. I have been taught that it was a particle when suddenly(i was expecting this) the teacher says that Electron has dual nature just like light(both particle as well as wave).I have...

Recently, I read the Stern-Gerlach experiment and I have a question about the source use free electrons beam instead of Ag atoms beam is the screen still two lines (electron spin up & down)? But the truth is that there is a region(pattern) not two obvious lines on the screen because the...

I am curious about the transparency of some materials to visible light. My physics is patchy and self taught, so I am hoping you can fill in a gap for me, or correct a misconception. So, transparency comes about when the light in question passes through a material with electrons that cannot...

Homework Statement An oxygen atom has a total of 8 electrons. Write the four quantum numbers for the each of the eight electrons in the ground state? I can't seem to figure this out. I know this... O = 1s^2 2s^2 2p^4 But from that, I don't know how to finish the question...

Hey All, I'm new to the forum. I hope I put this in the right area of expertise. If not, I would appreciate it if you could direct me to the right place. I am just a curious person with a pretty good physics background but I came up with a question I couldn't answer. Hypothetically, if you had...

i am really really confused . I know what Drift velocity is but the problem is I have three Sources which tell absolutely different expression for drift velocity and I cat relate . please tell which is right . This website and MIT Profs. Walter Lewin In his Lectures says Vd = eE/m x (Tau)...

I have learned that by rubbing, electrons are transferred from one object to another, making the gainer negatively charged and the loser positively charged. I also know that a proton is positively charged. Does it signify that a proton was once an entity that has lost its electrons?

http://en.wikipedia.org/wiki/Radioac...ng_decay_rates "...which are subject to electron capture in 7Be because (like all s atomic orbitals in all atoms) they naturally penetrate into the nucleus." How can the s orbitals penetrate the nucleus without being captured? And do they mean all...

Homework Statement The energy of the electron in the first and forth levels in a hydrogen atom are: (21.76*10^-19), (-0.85) e.V.. the electron moved from the forth level to the first level with one leap. Calculate: The frequency of the emitted photon from the atomHomework Equations ΔE = hfThe...

Who first assigned "negative" to electrons and "positive" to protons? a sort of history question... the fact that the actual flow of charge (which are electrons in metal conductors) is in the opposite direction of the "positive" current flow in circuits has always been an annoyance to me...

Homework Statement A metallic wire has a diameter of 4.12mm. When the current in the wire is 8.00 A, the drift velocity is 5.40 10^-5 m/s What is the density of free electrons in the metal? Express your answer numerically in m^-3 to two significant figures. Homework Equations I=nqv(drift)a...

Homework Statement Photons of energy 12 eV are incident on a metal. It is found that current flows from the metal until a stopping potential of 8.0 V is applied. If the wavelength of the incident photons is doubled, what is the maximum kinetic energy of the ejected electrons? Homework...

http://www.popsci.com/science/article/2012-04/first-time-electrons-are-observed-splitting-smaller-quasi-particles Sorry if this is old news or already posted somewhere, but could someone tell me more about this? (I know QM but not QFT, so if you can use QM terms that might be helpful). Thanks

if electricity is flow of electrons and also positive and negative charges attract then why electricity needs a conducting medium. electrons has mass and it should just travel through vaccum then why in vacuum electricity cann't travel please reply!

When picturing electric fields, they are always based on a positive test charge. As you move on to potential difference and electrical currents, it is based more on electrons/negative charge. So, why aren't electric fields and fields lines based on a negative test charge instead of a positive...

Hi All, I'm trying to visualize the flow of electrons in an AC circuit. DC is pretty simple as I can imagine the electron moving from point A to B. AC on the other hand confuses me. If there's a constant switch of polarity one would imagine that the electron would move forward as the...

Lets say, we have a cathode that emits electrons into the space under field emission and create a space charge in air.There is no arching of electrons to anode.We have hot dense gas which blow on space charge in certain direction.What would be the most likely outcome of interaction between...

Homework Statement I'm just trying to prepare a study pack for my final. I am curious about something I have been reading over in my textbook. Can someone please explain this for me? "Be able to explain why a two-slit experiment with electrons is evidence that electrons are waves" ...

Disclaimer: If this is the wrong place for this, I apologise, this probably comes somewhere between QM, Atomic, Linear algebra and a spoonful of Quantum chemistry for good measure. Anyway, for a group of non interacting (mean field) electrons, moving in a potential generated by nuclei and...

I'm reading about properties of electrons in atoms, and it says an electron's position in an atom can be described by energy level, shape, orientation, and spin roughly speaking: the energy level (n) dictates the radius from the nucleus (probability wise) the shape (l) dictates... the shape...

In a conductor suspended in an external electric field, in a vacuum, what holds the conducting electrons inside the conductor? Why don't they just fly off into space, under the influence of the field? If they are free enough to move between the atoms of the conductor, this means the force from...

Homework Statement Well,the problem is such : There are two hydrogen atoms.In each atom electrons were excited to the same energy level.Lifetime of one of the excited electrons is t1,when lifetime of other is t2. The question is : Which on of them had more wider spectral line,when during...

Homework Statement Calculate the drift velocity of the elctrons in a conductor that has a cross-sectional area of 8x10^-6m^2 and carries a current of 8A. Take the concentration of free electrons to be 5x10^28 electrons/m^3 with 1.6x10^-19C charge on each electron. Homework Equations...

I thought that electrons revolve around the proton faster when the material is hot, and slower if it's cold, if that's not true then from where do the electrons gain the energy to constantly revolve?

MRI imaging uses primarily the magnetic fields of spinning hydrogen protons to generate images. I read somewhere that the magnetic fields generated by spinning electrons are stronger then those created by spinning protons. Why then are electrons not used in MRI imaging? Thanks

Hi, I'm new to the forums, and I have a question. Here's the scenario: Let's say I have a circuit in a vacuum chamber with a current i, that flows through it and a constant voltage source and resistance in the circuit. One section of the circuit is a piece of gold (or any other conductor)...

Suppose we have an electron orbiting a nucleus,in an anti-clockwise direction, in a magnetic field, with field lines coming out of the paper/plane. If it has a particular velocity v1,it will experience a Lorentz force due to the velocity, towards the center of the orbit. We assume the extra...

I was doing some reasearch on electrons, and I found that they have both particle and wave like characteristics. Is this the reason why? because they travel in waves around a nucleus? or am I missing a piece of the puzzel? :smile: Cheers

Hi, Recently, I was thinking why electrons move so fast that we cannot even predict their exact position? I came up with an answer that electrons appear to move faster because their radius of revolution around the nucleus is very small compared to us. I was thinking if we could somehow...

http://t2.gstatic.com/images?q=tbn:ANd9GcT0sqrTGlvaB2RKBPMn759TUEtb-wfbrMz7OYYinYczpDndsVlt5Q MRI scanning create a hugh amount of magnetic field, does anyone have any suggestions how this strong magnetic field will affect the orbits of electrons within atom? Thanks in advance for any...

I want to understand the behavior of heavy electrons. For example is the mass actually changing? If so it would imply that a gravitational field could be affected by an electrical field. I am looking for good understandable references.

Explain that to cause a continuous flow of elctrons requires high positive potential and less gass pressure? Can anyone answer this please

My textbook (Halliday & Walker) explains that a charged conductor (a solid, of an arbitrary shape) in electrostatic equilibrium will have the electric field inside be 0 and all electrons will be on its surface. It proves this by saying that if the electric field inside was not 0, the free...

I was just thinking, as I do sometimes when my brain won't shut up and... If an electron is an elementary particle, and a positron is an elementary particle, why do they share so many properties, and yet are different slightly in almost every way. All the mass measurements show that the...

I am looking for a fairly simplistic answer to why different "shells" in atoms can only hold a specific number of electrons. There is so much based on valence electrons and how many electrons make a full shell but, do we know why atoms "seek" a full outer shell? It seems like there should be a...

When electrons jump from one shell to another energy has to be released right? Why is only light energy released? Why not other forms of energy?