All Questions
Tagged with electric-current electricity
791
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Understanding if possibly current density can be made scalar by changing the current definition?
In the accepted answer to this question : Why does current density have a direction and not current?
I understand the need for current density to be vector, but I am now curious if the definition of ...
- 235
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25
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Find the external work for getting the wire from $\infty$ to the current location. (the potential in $\infty$ is $0$)
A ball of radius $R$, with charge density:
$$\rho(r)=\beta r,\quad\beta > 0$$
A thin wire, with charge density: $\lambda[\frac{c}{m}]$ and length $R$, located between $x=2R$ and $x=3R$.
My ...
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Why Do Van De Graaff Generators Only Shock When Grounding Someone?
When someone touchs the metal sphere of the Van De Graaff Generators, the charge on them builds up, causing the famous hair raising. However, why is it when a person is rapidly grounded by someone ...
- 101
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How exactly is the value of DC in an AC circuit, given by the RMS of the AC
How and WHY does the RMS of current gve us the equivalent DC?
I've been though this answer here:-root mean square for dc
but it doesn't answer my question.
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2
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210
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Flow of Electrons in Potential divider circuit
Take the above circuit. I'm trying to understand how current flows through this potential divider circuit. I used the following simulation to help me visualize this.
In the simulation the electrons ...
- 69
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Potential divider problem [closed]
What does the curved arrow represent? The answer states that L1 will be dimmer than L2.
From my current knowledge, moving the contact K closer to X will somehow increase the voltage of L2 meaning it ...
9
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5
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4k
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Why is it easier to raise AC current to high voltage than DC?
In my country (and maybe all around the world I don't know) once electricity has been generated, it is then raised to 200k Volts for transportation.
I know this is to reduce the loss. Given $P=U.I$ ...
- 201
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2
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287
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Voltmeter connected to parallel circuit
This is my current understanding. Voltage is defined to be the potential difference between 2 points, hence it only makes sense for a voltmeter to be connected in parallel. But why must this voltmeter ...
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1
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46
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Why do we take electric field inside resistor constant? [closed]
Why do we take electric field inside resistor constant
0
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2
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357
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Voltmeter in parallel
I can't seem to understand the problem with connecting a voltmeter in series. All explanations say that voltmeters have extremely high resistance so connecting it in series will effectively stop the ...
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1
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19
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Electrostatic attraction between charges in different media
Imagine you have two non-conducting spheres of density a (a < density of water). Therefore the spheres float on the surface of water with a portion of their bodies immersed in water. Now how do you ...
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1
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Transformers in Power transmission [duplicate]
Recently I learnt that transformers are used in the national grid to increase the voltage, so we get less current. But my understanding V=IR and by increasing the voltage we get more current, so what ...
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Does the power state of an electrical device affect its likelihood of being struck by lightning?
Holidaying in the tropics, I have come across the following behaviors which are all intended to reduce the likelihood of attracting a lightning strike when in a storm.
Turning off the CD player/radio ...
- 21
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1
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296
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Why does an increase in drift velocity decrease electron collision?
The original statement is "The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased.". My understanding is, the temperature of a wire ...
- 419
2
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1
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135
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How does the magnetic force exerted to moving electrons in a current-carrying wire, actually transmit to the wire itself?
From my physics book I understand that the magnitude of the magnetic force is $F=qvB\sin(\phi)$. It is posteriously derived that the total magnetic force exerted to all electrons in a current-carrying ...
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