Why is the zero of electric potential taken to be r=∞r = \infty, rather than r=0?r = 0?

Wouldn’t it make more sense if it was taken to be zero at r=0? This seems to imply that with a negative test charge at r=0 from a positive point charge, V=−∞, which I have trouble conceptualizing properly. Is that accurate? Is there a better way to look at it? Answer You evidently understand that … Read more

Why is voltage described as potential energy per charge?

Voltage is often called an electromotive force since it causes a flow of charge. However, it is described in terms of Joules per Coulomb or Potential Energy per Charge. Question: How does the potential energy associated with charge contribute to its effect on the flow of charge? High voltage, or high electromotive force, causes high … Read more

From Poisson’s equation to Laplace’s equation [closed]

Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 2 years ago. Improve this question I want to understand how exactly ∇2V=−ρϵ0 turns into ∇2V=0. Of course it is by setting ρ equal to 0 … Read more

Is the vector potential component AϕA_\phi for a dipole necessarily 0 due to symmetry about the zz-axis?

Consider an electric dipole (+q(t), –q(t)) [where say q(t)=q0cosωt] is placed along the ˆz axis. In the spherical polar coordinates, its vector potential →A=Arˆr+Aθˆθ+Aϕˆϕ at any point M said to only be a function of r (radial distance) and θ. However, from here my professor directly concluded that the component along ˆϕ i.e., Aϕ should … Read more

Why does the potential across the terminals of battery increase on moving from negative terminal to positive terminal?

I really want to know that how does battery create a potential difference across the circuit. When we cross the battery from its negative terminal to positive terminal the potential rises by the voltage mentioned on the battery . So what exactly happens between the terminals so that the potential rises ?I know that the … Read more

Laplace’s equation: Why is ℓ\ell to be a non-negative integer?

I have got some mathematical difficulties in the following exercise: Calculate the potential of the polarized sphere along the z-axis. There are no free charges. For this, we need to solve Laplace’s equation, by using the method of separation of variables. ϕ(r,θ,ϕ)=R(r)Θ(θ) We obtain a partial differential equation on r and θ: 1R∂∂rr2∂∂rR=ℓ(ℓ+1) 1Θ1sinθ∂∂θsinθ∂∂θΘ=−ℓ(ℓ+1). My … Read more

Point charge potential (sign problem)

I’m a bit embarrassed, but I’m not able to compute the electric potential at point P (at a distance R from the origin) generated by a positive unitary point charge in the origin with the right sign. Simply use the definition V(P)=−∫P∞→E⋅d→l, forgetting the constant and choosing a straight line to integrate from infinity (so … Read more

Electric potential vs potential difference

What is the difference between electric potential and potential difference? In our course book, they are given as separate topics but their definition is given the same. Answer What is the difference between “electric potential” and “potential difference”? What is the difference between age and age difference? If age(person) is the function so that age(you) … Read more

Is voltage electric potential or electric potential difference?

On Wikipedia, voltage is defined to be the electric potential difference. However, I am still not certain as to whether voltage is the electric potential (PE/q) or electric potential change (ΔPE/q). My confusion partially comes from talking about circuits and defining the amount of volts a point in a circuit has. So, is voltage electric … Read more