B Current-carrying coil and solenoid

AI Thread Summary
The primary distinction between a current-carrying coil and a solenoid lies in their shapes. A solenoid is specifically a helical coil, while other forms of coils, such as toroidal or planar spirals, do not qualify as solenoids. Both structures consist of multiple turns of wire carrying the same current, but their geometric configurations define their classifications. The discussion emphasizes that the shape is the key factor in differentiating between the two. Understanding these differences is crucial for applications in electromagnetism and circuit design.
Meow12
Messages
46
Reaction score
20
What is the difference between a current-carrying coil and a solenoid?
 
Physics news on Phys.org
Baluncore said:
The difference is the current.
https://en.wikipedia.org/wiki/Solenoid
Assume that the same current I passes through the coil and the solenoid. Honestly, that picture in the Wikipedia article looks like a coil to me. It seems that both a coil and a solenoid have N turns of a current-carrying wire with radius r, and I don't see the difference.
 
Meow12 said:
Assume that the same current I passes through the coil and the solenoid.
Then the only difference is the shape of the coil.
A solenoid is a helix.
A coil wound on a toroid, or as a planar spiral, is not a helix, so not a solenoid.
 
This is from Griffiths' Electrodynamics, 3rd edition, page 352. I am trying to calculate the divergence of the Maxwell stress tensor. The tensor is given as ##T_{ij} =\epsilon_0 (E_iE_j-\frac 1 2 \delta_{ij} E^2)+\frac 1 {\mu_0}(B_iB_j-\frac 1 2 \delta_{ij} B^2)##. To make things easier, I just want to focus on the part with the electrical field, i.e. I want to find the divergence of ##E_{ij}=E_iE_j-\frac 1 2 \delta_{ij}E^2##. In matrix form, this tensor should look like this...
Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'
Please can anyone either:- (1) point me to a derivation of the perpendicular force (Fy) between two very long parallel wires carrying steady currents utilising the formula of Gauss for the force F along the line r between 2 charges? Or alternatively (2) point out where I have gone wrong in my method? I am having problems with calculating the direction and magnitude of the force as expected from modern (Biot-Savart-Maxwell-Lorentz) formula. Here is my method and results so far:- This...
Back
Top