Carrier Definition and 127 Threads

It is often said that the photon is the long range force carrier like the static force between electrons. Let's say we have two electrons galaxy apart, wouldn't the virtual particles have to travel long distances and "virtually" become real. And isn't the first sentence is wrong anyway since...

Hi Friends, I am Alen, doing research about light. I have submitted my thesis which contains few finding about light and utilizing maximum solar energy to produce electric energy from few square feet area. I got permission from my adviser to discuss on internet forum. I hope your commands and...

Generating a carrier on a single frequency is simple, just use an oscillator of a specific frequency and amplify. But how do I generate a carrier that is 100KHz wide, or even 100MHz wide? The obvious answer is more oscillators, but is there a better way?

Hi, I have this report to do on "Charge injection in heterostructures". I have been searching and reading but I still have some trouble with the basics, i.e. defining the concept. As far as I understood a heterostructure is a junction between two or more different semiconductors and the...

Hi, I have a question regarding the change in charge carrier concentration change. For a given semiconductor, say Silicon, when it is not doped, it is easy to understand that {n_0} \times {p_0} = n_i^2, however, on doping with donors to form a n-type semiconductor, we have {n_0} \approx...

I know that the virtual exchange particle between two electrons is the photon and this explains why they repel each other (ie virtual photon is spontaneously emitted from one electron A causing it to recoil. As the virtual photon hits electron B, it imparts momentum causing it to move away so...

Dear physics forums users, I'm reading a paper saying "For hole density p\sim 10^{17} - 10^{18}/cm^3, the screening length in silicon, \lambda_{Si}, is ~1-2nm." For this, the paper references Sze's, Physics of Semiconductor Devices. I'm unable to find the formula by which the authors seem to...

Hello ... Please , I want a transparent paint for a glass or plastic that carrier of electrical current. If it is existing in market ( what is the brand name) or there is a way to be manufactured by local materials available. Another question ... Is there a dry metal compound (powder)...

i have gone through that photon is force carrier of em force..but in macroscopic level as far as I studied I know em force is designated with field in macroscopic rather than a particle like interaction.so how can they justify that em force is managed by photon.If photon is more plausible is it...

Hello, What are the equations used to calculate the carrier, envelope and beat frequencies? Thanks

In the ni=\sqrt{Nc*Nv}*e^{\frac{-Eg}{2kT}} formula for intrinsic carrier concentration, what values Nc,Nv and Eg take in relation to temperature? Are they each calculated for that temperature or, for example, is Eg always taken for 300K? My guess is they should all be calculated for given...

An object floats if it is less dense than water. I'm assuming that an aircraft carrier can float because there are several rooms in it with air. What happens when the door on the upper most floor is opened? Does the air inside that room still contribute to the total average density of the...

I'm a bit unclear on terminology with semiconductors: is there a difference between the "intrinsic carrier density" and the "electron concentration" or "hole concentration"?

Can anybody give me or point me to a model that describes how electromagnetism works from a photon force carrier perspective. I like to know how the virtual photons are generated around an electron. Also why electromagnetism is polar. I am also confused why moving electric fields create magnetic...

Can anyone help me to find out the definition of "carrier swing"&"deviation ratio"? The definitions which i found on surfing the net is too vague.Can someone help me with this?

I am disappointed by the fact that receiver noise seems to be directly proportional to bandwidth. With a raised cosine shaped pulse transmitter the bandwidth is the more or less the reciprocal of the pulse duration. Short pulses mean large bandwidths and that means greatly reduced range, at...

I have been following this story for awhile, and since no one is reporting it, I thought I would post, because I feel you should be aware of what you may be subjected to when you use your cell phone. Have a look, comments, disbelief, outrage...

My general understanding was that they were created by fields, which makes me wonder how the LHC plans to detect the higgs boson... but I could be wrong

I'll elaborate. This year, in high school I started studying physics for the first time ever - I know, Mexico's Educational System is one of the Worst :\ - And I really, really liked it. The thing is, right here in mexico it is really hard to make a living as a physicist, and It's really...

how to joint two cylinder shaft which can make it turn 90degree anyone can give their opinion for me? :D

I got this from a friend over the internet...is this design practical or just some virtual design?

Hello all, I am trying to identify materials having a single dominant charge carrier having extremely low (on the order of 10^15 cm^-3) concentrations. Metals and extrinsically doped semiconductors, while both possessing a single dominant charge carrier (electrons or holes), tend to have...

Homework Statement The effective masses of n- and p-carriers in a semiconductor are given by mn* = 0.067me and mp* = 0.48me respectively. The gap width of the semiconductor is 1.45 eV. Use this information to find the intrinsic carrier density at 440 K. Homework Equations I have no...

Hi there, Not sure if this is in the best section, but here goes... I'm trying to establish how a formula from a paper I have read has been derived. The formula is: n=\frac{1}{qV} \int_0^I{\tau} dI where n is the carrier density, q is the elementary charge, V is the volume of the...

This is theorem 13.6 in Munkres' Elements of Algebraic Topology. I'm trying to go through this, but I can't prove it. Can someone do this one please? Btw, its "Choose a partial ordering of the vertices of K that induces a linear ordering on the vertices of each simplex of K. Define...

While reading about frequency modulation, I found that it was clearly written that the amplitude of the carrier wave remains unchanged. However, i didn't find a statement stating that the frequency of the carrier wave remains unchanged for amplitude modulation. So, is the frequency of the...

Homework Statement The aircraft carrier John F. Kennedy has mass 7.4*10^7kg. When its engines are developing their full power of 280000 hp, the John F. Kennedy travels at its top speed of 35 knots. If 70% of the power output of the engines is applied to pushing the ship through the water...

I have been told that the relationship n.p = (n_i)^2 always holds, where n_i is the intrinsic carrier concentration. This makes sense to me for an un doped semiconductor (sc.). However, for a doped sc., I'm a tad confused. For an n-doped material say, the electron conc. is...

I have a homework on Solid state device the question is :"If a Si sample is doped with 10^14 boron atoms per cm3 then determine the carrier concentration in the Si sample at 300K."[/b] I thought that the concentration is calculate by n = 2[(2pi*un*kT/h^2)]^(3/2) is this right formula ...

Hello, I am hoping someone out there can me better understand how an ADSL DMT carrier wave works. Is the carrier wave made of photons or electrons? I have tested the dry loop at my house and from what i can tell this is not an electrical circuit, but two open wires. This begs...

could time be the force carrier of mass? in other words maybe time is to mass sort of what electromagnetism is to photons. if so then we won't find a the Higgs boson because there isn't a conventional particle to detect. can we treat time like a particle in existing models?

what is the practical use of the concept of band gap other than classification between material? can free carrier absorption be manipulated by changing band gaps?

Homework Statement in Intrinsic GaAs,electron and hole mobility are 0.85 and 0.04 meter square/volt-sec and corresponding effective mass are 0.068m and 0.5m, where m=9.11*10^(-31)kg. band gap energy is 1.43 eV at 300K. ---calculate intrinsic carrier concentration(!) and Conductivity. Homework...

I need a LCC for low temperature measurement down to 10K or at least 77K. but I couldn't find any LCC capable of operating at that low temp. most commercially available LLC can only operate -70C. how you guys find a LCC operating below 77K? is it custom made?

Hope you can give me a hand here guys. I'm finding the whole carrier concentration thing a bit confusing! Si doped with say 10^17 P (/cm3). At 300K, calculate n, p, E_F (Fermi energy). Now I know the relations such as n=(N_c)exp[(E_c-E_F)/kT], N_c given I just can't figure out...

The Hall voltage across a 0.800-mm-thick conductor in a 1.30 T magnetic field is 3.2 uV when the current is 12.0 A. What is the charge carrier denisty in the conductor (in m-3). I was using the equation Vh=IB/ned where Vh is the Hall voltage I is the current B is the magnetic field...

Homework Statement The Attempt at a Solution The carrier wave is by inspection 0.5 + cos(10\pi*t) and the other would be 1.5*sin(60\pi*t). I'm not entirely sure what we're supposed to graph for the second part, the frequency spectrum. Any help?

hi yea umm is there any research/thinking regarding carrier wave signals being transmited vocally? jb

Hello; How do force carrier particles work? For example, if I drop an object, the force of gravity is carried by gravitons. Does this mean that there is a long stream of gravitons underneath/all around the object? Because the wave would need to be carried through the medium of gravitons. Is...

Hi all, I have a very basic question. I see a lot of "electron carriers" or "carrier electrons" terminologies. What does they actually means? Are they telling that electron as carrier for current? Because I thought that current is electrons that move from a point to another point, and that's...

Upon some calculation I arrive to the expression: d2DPn(x)/dx2 = DPn(x)/Lh2 Where: DPn(x) = Pn(x) + Pno - excess minority carriers (holes) concentration in the n-type part of the pn junction. Now the roots to the characteristic equation are +/- 1/Lh where Lh is the length of the...

What is the effective mass of a charge carrier, numerically? Is it equivalent to the mass of an electron? Is it the same for negative charge carriers as it is for positive charge carriers?

How does one calculate the intrinsic carrier concentration Ni for silicon as a function of temperature? I know the equation ni^2 = Nc*Nv exp(-Eg/kT) can be used, but then another equation is needed to find the energy band gap Eg. The effective density of states values Nc and Nv are well...

I need help finding the forces when an aircraft’s jump cable catches to stop a plane on an aircraft carrier ship. The aircraft is traveling at 110 mph with the front of the plane 3 feet off the deck of the ship. If the assumption is made that the cable stops the aircraft immediately (the cable...

Eg) Silicon Material When we say about mobility of a semiconductor - we basically have to consider its properties etc. One of it is impurities. Here we have to consider its TOTAL Dopant Concentration?

For example , optical carrier in the infra red region can provide higher capacity than microwave.

Hello. I am trying to teach myself some information about radio engineering. I keep getting stuck on the concept of carrier waves. I understand their uses and what they look like, but I do not understand what causes them or why they are needed. Any clarification or analogies would help. I only...

I am trying to understand what exactly the envelope is and why does the irradiance have twice its frequency? In class my teacher showed that when you sum individual waves, you get the carrier wave. Then my teacher showed something called an envelope, which looks a lot like an oscillating sine...

Homework Statement Your favorite radio FM radio station broadcasts at a carrier frequency of 94.7 Megahertz. What is the wavelength of the carrier frequency radio signal? Homework Equations velocity=wavelength(frequency) The Attempt at a Solution 94.7x10^-6(w)= 3x10^8 w= 3.2...

if particles can transfer force carrier particles to each other to generate forces between them such as quark -gluon exchange, is it an instaneous effect? or is it like gravity in relativity where the effects are not immiediately felt but take time such as for the force carrier particle to...