The current tag has no wiki summary.
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3answers
290 views
charge density in a wire
if we have a infinitely thin and infinitely long straight wire on the z-Axis with given current I(t), how can i compute the charge density?
I figured out that the current-density is given by ...
6
votes
2answers
336 views
Voltage and current of positive lightning
For a physics issues investigation I chose to investigate what effects lightning could have on an aeroplane while in flight if it was struck and then go on to discuss some possible implications of ...
2
votes
1answer
145 views
Frequency Response RLC circuit - Current against Frequency graph - Symmetry?
I understand that in a Frequency Response experiment dealing with an RLC circuit, the graph of Current against Frequency is supposed to be symmetrical about the resonant frequency theoretically.
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1answer
43 views
Understanding drift velocities in currents
I have a doubt about the understanding of drift velocities in a current. My problem is that the textbook speaks very loosely about this. It's like: "well, if we apply a field $E$ then the charges will ...
7
votes
0answers
138 views
supersymmetric Noether theorem and supercurrents — invariance requirements
Consider $\mathcal{N}=1,d=4$ SUSY, $n$ chiral superfields $\Phi^i,$ Kaehler potential $K,$ superpotential $W$ and action ($\overline{\Phi}_i$ is complex conjugate of $\Phi^i$)
$$ S= \int d^4x \left[ ...
4
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0answers
235 views
Relating the variance of the current operator to measurements
(EDIT: Thanks to Nathaniel's comments, I have altered the question to reflect the bits that I am still confused about.)
This is a general conceptual question, but for definiteness' sake, imagine a ...
2
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0answers
56 views
Current between supeconducting rings
How to calculate the current between two superconducting rings with radius r separated by a distance d?
Please note that being unfamiliar to the concept of superconducting rings, I can't approach ...
2
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0answers
78 views
How much current would be generated by polarity reversal of Earth's magnetic field?
Continuing from my previous question Is reversal of magnetic polarity in a planet an instantaneous occurence?
A change in magnetic flux is expected to generate an EMF.
In the case where the ...
1
vote
0answers
122 views
If we have a current I flowing down a wire, why must the net bound current be zero?
Say we are dealing with a wire that has a current I flowing through it, i.e. I is the free current. Why must it then hold that the net bound current, that is, the bound volume current, $J_b$, and the ...
1
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0answers
104 views
What is the weakest magnetic field that can practically be measured?
I would like to be able to measure magnetic fields that are generated by nerve impulses in extremities like in fingers.
I know that they are very weak: about 100 mV electric potential would give us ...
1
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0answers
59 views
Effect of Current on spring
When Current passes thru a spring , some books mention that it gets compressed.
However, I think due to the heating effect of current, molecules will increase kinetic energy and the spring should get ...
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0answers
17 views
What is the principle of active voltage balancing/equalizing device?
I am wondering about active voltage sharing devices. Their purpose is to equally divide voltages on slightly unequal super-capacitors. I found some papers like this, but it is too scientific.
I want ...
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0answers
43 views
Object accelerated by electromagnet
If I have an electromagnet (powered by a battery) and a metallic object, the
power generated will depend on the voltage of the battery and the resistance of the coil.
If I accelerate the object, will ...
