Potentials Definition and 244 Threads

Homework Statement The capacitors in the figure are initially uncharged and are connected, as in the diagram, with switch S open. The applied potential difference is V_{ab}= + 210 {\rm V} . What is the potential difference V_{cd} ? What is the potential difference V_{ad} after the...

Neuroscience -- Action Potentials, Voltage Clamps I'm trying to do a Neuroscience assignment and I'm a little confused about action potential behaviors especially when dealing with voltage clamps. First, when you are trying to measure the rate of an action potential propagation would you...

If the private messages supported latex, I could ask this directly from meopemuk, but I'll put the question here now. (Edit: very logical, I'm not even using latex here... well maybe the replies use latex) meopemuk, these instantaneous potentials you have been talking about seem very confusing...

I'm looking for a good book for graduate students that indicates how one can obtain a (classical) potential from a tree-level Feynman process. For example, how can one go from the S-matrix of e.g. Compton scattering and derive the Coulomb potential. Any help would be appreciated.

Hi, folks, Is the exponential (repulsive) term in Born-Mayer potentials supposed to be exp(-r) or exp(1/r)? - r is the interatomic distance; constants ignored I've seen both versions pop up in what appear to be reputable sources. The second one seems to be more popular, but, to me at...

Hi folks, A while ago I started a thread on N=2 SUSY QM, but unfortunately (fortunately?) the progress in my research is outpacing the progress in that discussion. :-p So I'm leaving that one on the back burner to skip ahead to shape-invariant potentials. I'm working from Chapter 5 of...

My question arises from study during my Human A+P class, but it goes beyond what I'd be expected to know for the class so I decided to post it here. When potassium exits the cell body during repolarization, is this due to its concentration gradient? If so, why does the chemical gradient get...

Homework Statement Use half-reactions and E's to determine the result of storing a solution of CuSO4 in a tin container. Homework Equations [Table of Standard Reduction Potentials of Half-Cells] The Attempt at a Solution My question isn't exactly how to do this question. I was just...

Hello, I am not sure if this is the right place to ask this, but I don't readily see a "numerical methods" forum here so I assumed this would be the place to go. Sorry if I overlooked another place to post this! Anyway, I have some points interacting via potentials that are dependent only on...

Homework Statement Suppose a wire carries a current such taht I(t) = 0 for t< = 0 = k t for t > 0 Find the electric and magnetic fields generated 2. The attempt at a solution trying to figure out vector potential first looking at the diagram s is the distance fro a point P to the wire which...

Homework Statement Homework Equations E=hc/λ? and the Time Independent Schrodinger Equation. The Attempt at a Solution Now, would I be right in thinking for the first section that the energy for the E=hc/λ bit is just the energy of the particle given in the question (10eV)...

Homework Statement Point X is 0.25m away from a point charge of +4.7 E -8 C, point Y is 0.65m away. What is the potential of point X with respect to point Y? Homework Equations delta Ep=delta Ek V=delta Ep/Q delta Ep=QV Ep=kQQ/d The Attempt at a Solution delta Ep = -Ep1 W=QV...

I'm attempting to reproduce the results in http://arxiv.org/PS_cache/hep-th/pdf/0611/0611332.pdf , notably the V_F(T) potential involved with the Kahler potential K = -2 \ln \left( \hat{\mathcal{V}} + \frac{\hat{\xi}}{2} \right) W = W_{0} + Ae^{-aT} \hat{\mathcal{V}} = \gamma...

Say you have a spherical conductor of radius a located inside the cavity of a larger spherical conductor of radius b, and that the larger sphere's outer radius is c If you charge the inner conductor at a to a charge Q, the inside part of the outer conductor becomes charged -Q and the outer...

I know the following ion/inside cell/outside cell Cl- 5mM 150 mM K+ 130mM 5mM Na+ 20mM 140mM Ca2+ 10^-4mM 2mM How would I find the reversal potential for conductance equally permeable to sodium and potassium? How do I find the reversal potential for a conductance equally permeable to...

I know the following ion/inside cell/outside cell Cl- 5mM 150 mM K+ 130mM 5mM Na+ 20mM 140mM Ca2+ 10^-4mM 2mM How would I find the reversal potential for conductance equally permeable to sodium and potassium? How do I find the reversal potential...

When we work out the E cell of with the electrode potential values of Zinc and copper (for example) Why does a positive E cell value indicate that the reaction is plausible?

1) The strongest reducing agent from those listed is: Use your book. a. Fe+3 b. Fe+2 c. Al+3 d. Al After looking at the chart of reduction potentials in my book, is it Al? 2) Select the reagent that will transform Fe+3 to Fe+2. a. H2 b. O2...

1. How does an Action potential start in the nerve. Does it just receive a stimulus and suddenly the inside of the nerve depolarizes??:confused: How does the inside of the nerve become more positive?? 2. In people with Multiple Sclerosis the myelin on the nerve is broken down & the AP doesn't...

The standard electrode potential of a Cu/Cu^2+ half-cell is given as 0.34V. However, the half-cell will only have this electrode potential relative to the hydrogen electrode when the concentration of Cu^2+ ions is 1mol.dm^-3. But won't most of the aqueous Cu^2+ ions form complexes...

Can someone just confirm the following: Change in potential energy of a charge, for example caused by moving two negative charges together is equal to the work done: Work done = Force x Distance = -qE * ∆X (Where E is electric field strength) = -qE∆X...

shapes of potentials! Hi all.. 1)we have,for example,rectangular, square well, well type etc potentials. How is the shape of a potential is determined? What is the shape of the nucleus potential? 2)I am unable to get the physical importence of the wave vector 'K' and K-space in band...

Choosing the Lorenz gauge implies that sources of the EM potentials at a given point are the charge density (for scalar potential) and current density (for vector potential) that cross a collecting sphere converging at the speed of light toward that point. It is often said that the retarded...

can anyone explain 2 me the fact that we don't have the concept of potentials in relativity...

This is about membrane potentials in a nerve membrane. I've already studied the Nernst equation and the Goldmann equation, but I have found its significance in explaining the resting potential. The Nernstian potential occurs at equlibrium, when concentration gradient = opposing electric...

The question says that charges are distributed with uniform charge lambda along a semicircle of radius R, centered at the origin of a coordinate system. What is the potential at the origin? I am not sure how to approach this one. Can anyone help me set this up and solve it? Thanks!

please elaborate ..." particle quantum mechanics is valid in the nonrelativistic regime by definition ...it refuses to obey relativity ...this is not bcoz we write non relativistic hamiltonians bt the concept of potentials is untenable in relativity ...since it assumes the transfer of...

A solid copper sphere whose radius is 1.0cm has a very thin surface coating of nickel. Some of the nickel atoms are radioactive and emit an electron with each decay. Due to the geometry of the situation, half of these electrons enter the copper sphere, each carrying away a charge of -e. The...

anyone here have knowledge on computing Lennard-Jones potentials for molecules using periodic boundaries versus doing it on the 3D surface of a hypersphere?

Hello! I am right now occupied with statistical physics, and of course the connections to thermodynamics are always there. We are especially verifying the old-school thermodynamical results. This leads to a lot of talking about thermodynamical potentials, but I feel that I and most of the...

A hollow cylindrical shell of length L and radius R has charge Q uniformly distributed along its length. What is the electric potential at the center of the cylinder? I use eta = Q/A = Q/2piRL dq = (eta)*dA = Q/(2piRL)*2piRdL dV = 1 / 4 pi epsilon 0 * dq/r where r = sqrt(L^2+R^2) V...

ok I've "hit the wall" on this question and I am wondering if someone could help me a +charge q1 is located 3.00m left of a -charge q2. the charges are not equal in magnitude. There is 2 spots on a line through the charges where the potential is 0. 1 spot on this line where the electric...

Why is it that all the potentials that we use in QM are classical ? For example the columb potential. Shouldnt we use a wave equation for the potential as well as for the position?

Inside a shell of matter I would experience a flat gravitational potential and hence no gravitational force. Is there any experiment I can do, short of leaving the shell, that could allow me to determine the existence of the potential? For example would my extra potential energy show up...

Let’s say we have a 1 mol system in a state A (Pa,Va,Ta are given) and we take it to a state B(Pb,Vb are given) . We want to know what’s the maximum work we can give to a reversible work source. Considering the process is carried out attached to a 150 K heat source, the only data available is...

I just learned the scalar and vector potentials arising from the electric and magnetic fields have a physical reality in relation to quantum mechanical effects, such as the Aharonov-Bohm effect. Contrary to what I've learned from my course on electrodynamics (Griffiths) this sure must mean they...

Dear friends, I’m having trouble with this thermodynamic problem. I apologise if you don’t understand my poor English (I’m writing to you from Spain!) We’ve got two cylinders (1 is adiabatically isolated from 2 but not from the outside, where Pressure P and Tº are constant) and cylinder 1...

What exactly are they? CAn you maybe explain it 2 me in terms of electromagnetism. I am a bit unsure what each of them actually are

The electric potential along the x-axis (in kv) is plotted versus the value of x, (in meters). Evaluate the x-component of the electrical force (in Newtons)on a charge of 5.10 micro-C located on the x-axis at x=2.8 m. http://www.geocities.com/vsage3/p.bmp I tried finding the value of kV...

Two concentric spheres of radii 1.65 cm and 19.0 cm, respectively, are given equal but opposite charges of 6.35e-08 C. How much energy is stored in the system (in J)? I know V = U/q where U would be the entire energy stored in the system beacuse it's not in motion. I know q's but I just...

I have a question concerning the stationary states of a spherically symmetric potential (V=V(r), no angular dependence) By separation of variables the eigenfunctions of the angular part of the Shrödinger equation are the spherical harmonics. However, (apart from Y^0_0) these are not...

Living cells actively pump sodium ions inside the cell to outside the cell. Given that the electric potential is 0.070V higher outside the cell than inside the cell and that the cell membran is 0.09E-6 meters thick, how much work must be done to move one sodium ion from inside the cell to...

From what I understand, the release of neurotransmitters into the synaptic cleft and the consequent binding of these to their respective receptors on the post-synaptic membrane can have one of the following effects: - excitatory: K+/Na+ ligand-gated ion channels are opened and the local...

Here is the largest part of the chart that will fit on a post. ___U.V.______lavender_____violet______indigo__ 3.650E-07___3.864E-07___4.097E-07___4.339E-07 - visible light 7.301E-07___7.729E-07___8.195E-07___8.679E-07 1.460E-06___1.545E-06___1.639E-06___1.735E-06...