# Tagged Questions

The study of the presence and flow of electric charge. Charges, currents, fields, potentials.

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### Why can't I connection the anode of a battery to the cathode of an other battery and get a current flowing? [duplicate]

If I touch the anode of a battery or connect the anode the the cathode of an other battery, none (or rather: a very small current) flows between those two. If I instead connect the connect the anode ...
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### How did the author derive the distance the particle takes as $\dfrac{h}{\cos\theta}$?

On Page 292 of Griffith's Introduction to Electromagnetism (3rd ed.) he mentions that the a basic for of a generator is one in which one pulls a square wire with one side of it in an uniform magnetic ...
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### What is the real derivation of Ohm's law? [closed]

$I$ is proportional to $V$. But then how it is that I directly got $V=IR$? It looks impossible to handle this thing! If $I$ is proportional to $V$, then it must be $I=RV$. Why it is $V=IR$? The ...
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### Relationship between electrical resistivity and density

I just read this answer on EE.SE and that triggered a doubt in me. If I were asked whether there is any relationship between the electrical resistivity and the density of a substance I'd answer ...
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### Is it possible to calculate the energy of a spark?

I am not a physicist, but this question came to me and I need to answer it, and I think that you guys can help me. Is it possible to calculate the energy in a spark? For example in a lighter with ...
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### Electricity consumption in fan

Does regulation in a fan vary in Electricity consumption? i.e. I want to know exactly, is the energy consumption more when regulator is tuned to highest number or lowest number?
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### How can I calculate the Teslas and resistance of an electromagnet?

I'm trying to build a small electromagnet to use in a generator. Right now, I have a coil of insulated 16 AWG copper wire wrapped around a large iron nail with a diameter of 1.5cm. The length of the ...
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### (Capacitance of a battery?) Finding the charge accumulated on a rod

We all know the expression for the potential difference across a conducting rod moving through a region with a uniform magnetic field: $\epsilon = B l v$ Now my question is different. Is it ...
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### What trioboelectric materials create the best charge?

With developing the maximum triboelectric charge in mind: What roller and belt material combinations can I easily/cheaply buy at the local hardware store to make a Van de Graaff generator? I've ...
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### Why is there no charge in a capacitor connected to one battery pole? [duplicate]

Here is a very simple drawing of a battery pole and a capacitor plate connected by a wire (exaggerated in thickness). The question is, why is the capacitor not being charged? But as you will see ...