Potential Definition and 1000 Threads

I have seen the other threads on an infinitely long wires vector potential.Its obvious that really small wires are just infinitely long cylinders: ∇xA=B ∫∇xA.da=∫B.da ∫A.dl = ∫B.da = φ(flux) For an infinite cylinder A.2πri=B.2πrih A=Bh A=μ0*I*h/(2π*r) Now for a cylinder of radius limr->0 =>...

Homework Statement A particle of energy E moves in one dimension in a constant imaginary potential -iV where V << E. a) Find the particle's wavefunction \Psi(x,t) approximating to leading non-vanishing order in the small quantity \frac{V}{E} << 1. b) Calculate the probability current density...

What should be the potential of a cube at infinity having 6 equal charges placed at its corners?In first attempt I made it zero as looking from infinity all tge 8 pt. charges will seem to be coincided at a single point and potential of a 8q charge at infinity would be zero..?

Homework Statement If the electrons hit the tungsten target with an energy of 75 keV, find the potential difference. Homework EquationsThe Attempt at a Solution I tried this: (W=eV) V=W/Q V=eV/Q V=75,000/1.6*10-19 V= 4.6*1023 V, This seems wrong because all examples in my...

Homework Statement I am trying to figure out the average penetration depth into a finite step potential, similar to this thread: https://www.physicsforums.com/threads/qm-barrier-penetration.104641/ But instead of just estimating the depth as ##\frac{1}{\kappa}##, i would like to calculate it...

Hi, I know that in an elecric field the potential energy ##E_{pot}## is equal to the potential ##V## times the charge ##E_{pot}=q V##. Here my problem: I know that the potential energy of a spring is ##E_{pot}= \frac{1}{2}kx^2##. In my theoretical physics book i read also that the potential is...

in this problem i can solve v = ω x r = <0, -ωrsinψ, 0> in cartesian coordinates but i don't understand A in sphericle coordinates why? (inside) A = ⅓μ0Rσ(ω x r) = ⅓μ0Rσωrsin(θ) θ^ how to convert coordinate ?

Homework Statement Homework Equations Emec - PE = KE The Attempt at a Solution When particle starts at x = 4 KE = .5(.25)(225) = 28.125 Energy of system = 28.125 I don't have anything with position here so i am unsure how to find what position that the energy will be equal to the Emec and...

Homework Statement All the bulbs in the circuits are identical, as are all the batteries. Rank the magnitude of the potential difference between points M and N. Homework Equations V=IR The Attempt at a Solution My most fundamental question is actually which way do I know to take the...

Homework Statement https://www.physicsforums.com/attachments/upload_2018-4-29_12-40-30-png.224871/ Homework EquationsThe Attempt at a Solution 1/2mv^2=10 1/2m(ucos60)^2=10 1/2mu^2/4=10 mu^2=80 what to do now?

Could a particle near a black hole about to enter rid the string of its vibration?

I am sure that the vector potential of a toroid isn't 0 even though its magnetic field is , does anyone have a derivation for the its the vector potential at a point P(x,y,z) outside the toroid ? i expect that since its curl is 0 we have a general form of : A = f(!x)ex + g(!y)ey+m(!z)ez Such...

Homework Statement I have a problem understanding the equation $$\Delta V = -\int_{a}^{b} \vec{E} \cdot d \vec{l}$$ In the case of a parallel plate capacitor whereby the positive plate is placed at ##z=t## while the negative is at ##z = 0##, my integral looks like $$\Delta V = -\int_{0}^{t}...

If the electric field of a line charge at a distance 'a' is µ/2Π ε0a (µ is linear charge density), then the potential at that point should be µ/2Π ε0 (since potential = electric field x distance). This means that the potential is constant at every point around the line of charge. Hence, this...

I have two isolated plates A and B, kept parallel to each other. Now I give charge +Q to the plate A, it will redistribute itself as +Q/2 on the outer plate A and + Q/2 on the inner plate A. Right? Now this will induce charge -Q/2 on the inner plate B and +Q/2 charge on the outer plate B...

Homework Statement Let’s say I have got a charge density $\rho (x,y,z) = \cfrac{C}{x^2}$ with C a specific constant. I want to know the potential on every point in space. How can I get an expression of the electric potential in terms of position? Homework Equations Gauss law/coulomb's law...

Hi, I have a question about calculating probabilities in situations where a particle experiences a sudden change in potential, in the case where both potentials are time independent. For example, a tritium atom undergoing spontaneous beta decay, and turning into a Helium-3 ion. The orbital...

Homework Statement Two cells of same emf E and different internal resistance r1 and r2 are connected in series to an external resistance R.The value of R for which the potential difference across the first cell is zero is given by (A) R=r1/r2 (B)R=r1+r2 (C)R=r1-r2 (D)R=r1r2 Homework Equations...

When the eletctric field was defined I could totally relate to E is like g in mechanics. But for the electric potential I don't know. What would be equivalent analogy?

Hi, a fast question... I was having somekind of a discussion, and I actually hit a dead end to the way I could explain my statement. I believe that after the Higgs Mechanism and SSB, the resulting potential of the Higgs Field should no longer be symmetric to rotations : I am saying this because...

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...

Hi all, i tried to do this question but got stuck on the last point . Can anyone help me please? The general form of vector potential: I got the answer for A1 vector potential but don't know what assumptions i need to get the expression for the A2. Does anyone know how one can derive it...

So we have the Newtonian gravitation potential given by ##\phi_M(r)=-GM/r##, and in class the teacher said that the Newtonian force is given by ##F_m = -m\nabla \phi_M(r)##. Now, I was thinking about what was taught in UG or high school, isn't the force should be ##F_m = GmM/r^2##, if I plug...

Homework Statement Homework Equations ##ΔV=Ed## The Attempt at a Solution ##V_A=E l## ##V_b=0## , because point B is perpendicular to the electric field ##ΔV = V_a + V_b## = El Is my answer correct ?

Homework Statement A potentially silly question that I have put off too long to ask, any assistance is greatly appreciated! The electric field evaluated along the Z axis of a ring of charge centered on the origin and lying on the XY plane is only a function of ##z## and points only along...

Homework Statement Homework Equations The Attempt at a Solution Is my answer correct ?

Please refer to the image attached. So, my doubt is: While calculating dW in the derivation, we know this work is being done by external force, because only then the unit positive charge can be made to move towards the charge +Q. So dW should be equal to Fext.dx but here in the book it is shown...

I think mass as a form of potential energy and am always told that this is wrong. According to wiki: "In physics, potential energy is the energy possessed by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors." Why do this...

Homework Statement Homework Equations ##V= \frac {kq}{r}## ##V= \frac {U}{q}## The Attempt at a Solution ##V= \frac {kq}{r}## = 9*109*-5*10-9 /0.1= -450 V ##U= \frac {V}{q}## = -450 * -2*10-9 = 900nJ Is my answer correct ?

Homework Statement Homework Equations V=¼*(1/(π∈) * ∫(ρs/(R')*ds' where R' is distance from point to surface R'=|R-Ri| distance from observation point to location of surface charge density. The Attempt at a Solution So my attempt was to define R' as R'=√((-r)2+(-Φ)2+(z)2). Then I said...

Homework Statement Homework Equations V = kq / r The Attempt at a Solution VA = k q / rA VB = k q / rB rB = √((√8 * R)2 + R2) = 3 R VB = k q / 3R ΔV = | VA - VB | = | kq / R - Kq / 3R | = 2 kq / 3 R Can somebody check my answer please ?

Homework Statement Hi I'm attempting to derive the gravitational potential energy of a point mass (##m##) that's moving from infinity to a point r' inside a gravitational field produced by a another mass ##M##. For simplicity I treated it as a one dimensional case. The problem I get is that the...

Homework Statement The photon is normally assumed to have zero rest mass. If the photon did have a tiny mass, this would alter the potential energy the electron feels in the hydrogen atom (due to the Coulomb interaction with the proton). The potential then becomes yukawa potential...

Homework Statement Homework Equations V=kq/x The Attempt at a Solution I know the correct solution. It's... On my first attempt, rather than use (d+x) in the denominator and integrate from 0 to L, I instead used (x) and integrated from (d) to (L+d). This produces the wrong answer...

Homework Statement Homework EquationsThe Attempt at a Solution If we consider the bigger semicircular arc BD alone then potential difference between B and D will be 4BvR . If we consider smaller semicircular arc AC alone then potential difference between A and C will be 2BvR . If we...

Homework Statement Homework Equations K = (1/2)mv2 U = mgh W=Fd Integration/Calculus The Attempt at a Solution I'm not sure what I should be doing for this question, if height changes how is it possible that velocity stays the same, according to the conservation of energy (frictionless wire)...

Homework Statement Two equal line sources of strength k are located at x = 3a and x = −3a, near a circular cylinder of radius a with axis normal to the x, y plane and passing through the origin. The fluid is incompressible and the flow is irrotational (and inviscid). Use the Milne-Thomson...

Homework Statement Homework Equations Equations of Lienard Wiechert Potential The Attempt at a Solution I had used the equation of scaler potential. I don't understand how to use angle 60 degree is this equation. suggestion needed

How does the Higgs scalar potential evolve with temperature? Is there possibility they are independent? Besides temperature. What else can theoretically affect the higgs scalar potential?

1. Homework Statement : A graph of the x component of the electric field as a function of x in a region of space is shown in the figure [attached] below. The scale of the vertical axis is set by Exs = 47.5 N/C. The y and z components of the electric field are zero in this region. Suppose that...

Homework Statement Alright, this is a Lab Exercise, so it's light on an actual introduction and data, but I'll do my best to put into words the whole thing. The gist of it is that we have a Vat with water, a millimetre paper at the bottom, and we put two Equipotential surfaces inside. We charge...

I am to use this formula: https://d2vlcm61l7u1fs.cloudfront.net/media/fee/fee798ea-5480-47af-9904-35c76ac35e25/phpSzecLa.png I tried using intergral of (E*dr) as in the equation to integrate over the distance of V(2A)-V(0) But when i am to plug in zero into my integrate it would give a math...

Homework Statement Determine the potential that creates an undefined cylinder of radius $R$ and density density $\rho$ that is uniformly charged. Homework Equations Gauss's law. The Attempt at a Solution I know that for this problem I can use gauss because it is a cylinder, now I do not get...

Homework Statement Two frictionless pucks are placed on a level surface, as shown(see diagram) at an initial distance of 20.0m. The mass of puck 1 is 0.80kg and has a charge of +3.0 x10-4 C, while puck two has a mass of 0.40 kg and a charge of +3.0 x10-4 C. The initial velocity of puck 1 is...

Homework Statement They're in the attachment Homework Equations V=kQ/r The Attempt at a Solution I was absent during this class,so I have no idea,but I attempted question a which is the potential at point a,b Point a=(9*10^9 * 10*10^-6/0.2) Point B=(9*10^9 * -8*10^-6/0.3)

I worked problem 2.28 of Nayfeh and Brussel's Electricity and Magnetism. The problem asks for the potential near the center of a charged hollow sphere, based on the near-field expansion given by equation 2.62, which is: ##\Phi=\frac{1}{4\pi\epsilon_0}[\frac{dq}{r^\prime}+ \vec r \cdot \int...

Hello people, I have 3 questions related to the mean speed of electrons in a period potential /lattice. I've read Ashcroft and Mermin's page 139 as well as the Apendix E. From what I understood, if one applies the momentum operator on the wavefunction of a Bloch electron, one doesn't get a...

Homework Statement [/B] I have the following expression: $$S=T+V$$ $$T=\frac{m}{\tau_0+it}((x_1-x_0)^2+(x_2-x_1)^2)+\frac{m}{2(\tau_1-it)}(x_2-x_0)^2$$ $$V= \frac{(\tau_0+it)}{2}(\frac{k_0 x_0}{2}+\frac{k_0 x_2}{2}+k_0 x_1)+(\tau_1-it)(\frac{k_1 x_0}{2}+\frac{k_1 x_2}{2})$$ The main goal...

First, I'll give a little background so you guys know why I've arrived at this issue. I'm writing my BSc thesis right now, and the point of the thesis is to predict the bound states of two-nucleon systems (one bound, others not) by treating the problem as a simple QM two body problem. With a...

Homework Statement As an electron (q2) moves from point A to point B, it moves farther from a positive charge (q1). Does the electric potential energy increase, decrease, or stay the same. Homework Equations U=-kq1q2/r The Attempt at a Solution The electric potential energy decreases in...