How does a 'open surface' of a closed loop look like?

AI Thread Summary
The discussion focuses on the visualization of the "open surface" of a solenoid in the context of electricity and magnetism, referencing Walter Lewin's lecture. Participants clarify that the correct term for the surface in question is "helicoid," distinguishing it from a Riemann surface. A Riemann surface is explained as a mathematical concept used to visualize different branches of a function and their relationships. The conversation highlights the importance of precise terminology in understanding complex concepts in physics and mathematics. Overall, the distinction between helicoids and Riemann surfaces is crucial for accurate visualization in these fields.
serverxeon
Messages
100
Reaction score
0
im on the topic of electricity and magnetism, and came across walter lewin's lecture.

i cannot visualise how the 'open surface' of this solenoid will look like

b7f9ye.png


is the open surface a riemann surface? or something else?

[PLAIN]http://wiki-images.enotes.com/thumb/b/b5/Riemann_sqrt.jpg/180px-Riemann_sqrt.jpg

thanks
 
Last edited by a moderator:
Physics news on Phys.org
I believe the correct terminology is helicoid.

A Riemann surface is something else entirely. I'm not a mathematician, but as I understand it, a Riemann surface is just a way to visualize different branches of a function and how they are related to each other.
 
Thread 'Gauss' law seems to imply instantaneous electric field propagation'
Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
Maxwell’s equations imply the following wave equation for the electric field $$\nabla^2\mathbf{E}-\frac{1}{c^2}\frac{\partial^2\mathbf{E}}{\partial t^2} = \frac{1}{\varepsilon_0}\nabla\rho+\mu_0\frac{\partial\mathbf J}{\partial t}.\tag{1}$$ I wonder if eqn.##(1)## can be split into the following transverse part $$\nabla^2\mathbf{E}_T-\frac{1}{c^2}\frac{\partial^2\mathbf{E}_T}{\partial t^2} = \mu_0\frac{\partial\mathbf{J}_T}{\partial t}\tag{2}$$ and longitudinal part...
Thread 'Recovering Hamilton's Equations from Poisson brackets'
The issue : Let me start by copying and pasting the relevant passage from the text, thanks to modern day methods of computing. The trouble is, in equation (4.79), it completely ignores the partial derivative of ##q_i## with respect to time, i.e. it puts ##\partial q_i/\partial t=0##. But ##q_i## is a dynamical variable of ##t##, or ##q_i(t)##. In the derivation of Hamilton's equations from the Hamiltonian, viz. ##H = p_i \dot q_i-L##, nowhere did we assume that ##\partial q_i/\partial...
Back
Top