All Questions
Tagged with electricity electric-current
97
questions with no upvoted or accepted answers
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What's the expression relating conductivity with temperature?
In this image, σ is the conductivity, n is the number of electrons per unit volume, λ is the mean free path of the electrons, v (with subscript d) is the drift velocity of electrons, and T is the ...
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Volt, Ampere and Ohm in real life
Long story short, i am a what some would call a visual thinker; i think in photos and videos. If i can't visualize it, i'm having a very hard time understanding it. For that reason, i've never ...
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Experimental material impedance measurement
Imagine you have a square-shaped plate of conductive material to which you connect 3 electrodes E1, E2, and E3 (as shown in figure below). Suppose we assume for this plate a 'pi' (aka delta) two-port ...
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Applying KVL to batteries with different EMF in parallel
Consider the circuit diagram below-
Two batteries of different voltages are placed in
parallel, however as I was told that KVL is applicable to all loops if there is no varying magnetic fields, ...
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63
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Charging a single plate of a capacitor does not work
I charged a 100nF capacitor with 12V with a battery, then i disconnect the battery from the capacitor and connect the positive side of the capacitor to ground (which is an electron source) ...
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89
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What's the magnetic field produced by a current carrying circular loop at a point on its plane?
How do I find the magnetic field in this case? I already know about the magnetic field produced by a current carrying loop at an axial point or center but what about the point on its plane?
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How is electric current possible if no electric field exists inside a conductor?
How is electric current possible if no electric field exists inside a conductor?
Since no electric field exists inside a conductor. How is electric current possible as $$v_d=\frac{(eE)t}{2m},\;\;{E=0}...
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Why do potential difference between the terminals of an ideal battery remains equal to its $Emf$ even if it is connected externally
In an ideal battery, the battery forces are equal in magnitude to the electric forces (the ones that are present when battery is not connected externally) and thus we conclude that E.M.F. ($\...
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147
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How do the electric field lines distribute inside a current carrying conductor?
We know that when we connect a conductor to a source of potential difference, an electric field is established inside the conductor. With the help of calculations which I show below, we can see that ...
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151
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Why the readings of wattmeter in both cases coming out the same even though they are connected at different places?
The value of resistance is 3Ω and inductor impedance is j4Ω.
As far as I have learned the wattmeter measures instantaneous power but shows reading for average power. As I solved for the given values ...
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134
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Doubt regarding the flow of charge between the primary cell and secondary cell in a potentiometer
In the potentiometer, if the emf of primary cell and secondary cell are not equal, then the wire connected to primary cell and secondary cell will have different potential. Suppose the emf of the ...
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307
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Free electrons in materials with high resisitivity
I want to understand why exactly resistors or materials with high resistivity difficult the flow of current. If I'm not mistaken, there are not many free electrons in this materials to move and ...
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163
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If a light bulb is connected to different voltages, is there a single method to calculate the utilized power?
If a bulb is marked at 100W and 200V, we know that the bulb utilises a power of 100W when connected to a 200V potential difference. So, can we say that the bulb, when connected to twice the potential ...
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132
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Why is current density assumed to be uniform in following scenario
This was homework question, and i got it right. But i still don't understand why.
Assume that we have some glass rod, which is heated. At the ends of the glass rod potential difference $\Delta V$ is ...
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Current equation $I=nqA\vec{v}_d$
I was reading from several introductory E&M materials, and they all state that $$I=neA\vec{v}_d$$where $n$ is number of free charge carriers, $e$ is the elementary charge of electron, $A$ is cross-...