All Questions
Tagged with electricity electric-current
791
questions
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Is the speed of signal transport via electricity as fast as light? [duplicate]
Let us assume a time synchronization system that comprises a sender and a receiver. The sender generates and sends an encoded signal which presents the current time to the receiver periodically, and ...
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1
answer
63
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Question regarding power consumption by a device running on electricity
Say I have a device with resistance $R_2$, connected through a wire of resistance $R_1$ to a source providing potential difference $V$. If I close the circuit then current $I$ will flow through, and ...
- 1,168
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1
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175
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How is Lorentz Force $BQv=BIl$?
The formula for Lorentz Force on moving charge is $$F=BQv$$ which for current carrying wire is modified to $$F=BQv$$$$=BQ\frac lt$$$$=BIl$$
Where $l$ is the length of the wire inside the magnetic ...
- 1,168
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1
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191
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Motion of the electrons in a electric conductor when connected to a potential difference?
(I am a beginner in physics, so please forgive me if this is stupid.) Normally, under static electric state there is no resultant electric field existing inside a conducting material. But, when a ...
- 201
2
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3
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66
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How does the actual power of the device depend on the angular frequency of the voltage? [closed]
The voltage source produces a sinusoidal AC voltage. An electrical device with resistance and inductance is connected to the source. How does the actual power of the device depend on the angular ...
user331916
1
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1
answer
225
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High voltage in transmission line [closed]
I'm trying to understand why high voltage is used in transmission but I seem really confused by the explanations I read.
Here's what I could make out:
$$P_\text{loss} = \dfrac{ΔV^2}{R_t} = \dfrac{(...
- 349
3
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2
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299
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What makes a lightbulb glow?
I am self-studying electricity and magnetism, and I am confused about a point.
I have learnt that the drift speed of an electron is extremely small. However, according to Drude's model, the electron ...
- 268
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2
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82
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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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1
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141
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Why were electrons chosen to be negatively charged? [duplicate]
Wouldn't it make more sense to call electrons positively charged because when they move they make electricity?
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1
answer
89
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Does an open circuit have electrons accumulate in it?
This is what I have imagined electricity to be like, where the blue balls represent the free valence electrons in a conductor atom, and the electrons flow towards the positive electrode as the ...
- 1,168
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1k
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In which direction would the galvanometer's needle deflect when the current enters through the red lead?
Imagine that this is the galvanometer, and we attach the red terminal of a power source to the red terminal of the galvanometer, and the black terminal of the power source to the black one of the ...
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6
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Why are lightbulbs with lower resistance brighter in parallel circuits, but lightbulbs with higher resistances are brighter in series circuits? [closed]
When multiple lightbulbs are involved, why would a lightbulb with more resistance emit more light in a series circuit, but less in a parallel? (Pictures for reference)
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6
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3
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2k
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Why don't stationary charge feel force from a current carrying wire?
The current carrying wire doesn't apply any magnetic force on nearby charge $q$( positive stationary charge) because it has 0 velocity in lab frame. We found that there is no force on q by wire. But ...
- 79
2
votes
1
answer
21
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Change the current draw of a circuit without a potentiometer [closed]
I wanted to know how is it possible to alter the current that is being received, simply via a press of a button in a circuit. I am referring to this part of the video https://youtu.be/hFLopMOIjc8?t=...
- 39
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3
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124
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$I$ proportional to $V$ or vice versa?
I am confused whether Voltage depends on current or the vice versa. I always thought that the vice versa was correct. I tried to find the answers of some of my other conceptual doubts on the web but I ...
0
votes
1
answer
89
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How Electric field is generated inside wire when a voltage source is connected to it? [closed]
I have found by my searches that the electric field inside wire is generated by the positive or negative charges accumulated at the surface of wire.
My question is, Why do charge get accumulated on ...
user316791
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1
answer
30
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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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5
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3k
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How does the electrical ground rod work?
I was reading this article about shock current path, but it seems to be contradicting answers that I have seen on this site regarding electric shock. I can't find the original question but it was ...
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3
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131
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What exactly is AC Amperes
In the case of AC, electrons don't go anywhere. So what exactly are amperes in the case of AC current? It is supposed to be the measure of AC current, But obviously, I would argue that since electrons ...
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1
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2k
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Why increasing the resistance in a series circuit decreases the current in the circuit?
Concise Physics mentions that:
On connecting one more appliance in the same circuit , the resistance
of the circuit will increase . Hence , it will reduce the current in
the circuit , so each ...
-2
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3
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312
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What is meant by Electrical resistance and Electrical resistivity? Some different thoughts needed
The Electrical resistance is defined as the oppose of flow of charge by a material(wire for example). Also $R = \rho l/A$
What i think is that "charge" here actually means the magnitude of ...
0
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1
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45
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How does the electric field pattern looks like when current is moving inside the conductor and why this field is uniform?
We know that electric field is uniform inside a normal electric circuit consisting of some battery source and a conducting wire , $\mathrm{E}$ will be $\mathrm{E=V/d}$ , but I cannot think of a reason ...
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1
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1k
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Danger to swimmer from lightning?
Having been swimming a few times recently when a thunderstorm developed, I've started wondering what the actual dangers are (please note - I'm more interested in this from a science perspective; I get ...
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1
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32
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How are the electrons able to overcome the significant force of attraction of the ions?
The cause of electrical resistance(in a metal) is electrons colliding with themselves and the positive ions. So if the electrons collide with the positive ions, how are they able to overcome the ...
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3
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100
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What is the definition of direction of current?
Wikipedia defines the direction of current as:
The direction of conventional current is arbitrarily defined as the direction in which positive charges flow.
But suppose a region where there is a non-...
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2
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203
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How does the high potential difference between the two points ionizes the air?
As we can see that for some instance air can tolerate the potential difference between two points without any high leakage current and when this potential difference between the two points becomes too ...
- 952
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2
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84
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What will happen if both electrons and positive charges got ability to move inside the conductor?
Let's consider a conductor which has a potential difference across its ends.
And let's say that the electrons which already have tendency to move inside the conductor, by all of a sudden if positive ...
- 952
7
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5
answers
3k
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How does a resistor "know" to increase the potential difference across its ends?
My book says that current has to be constant throughout a simple series electrical circuit consisting of wires, a cell and few resistors, and hence resistors have higher potential difference across ...
- 1,168
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1
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43
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Confusion regarding drift velocity and potential
From this post I understood that the drift velocity of electrons decreases further into the circuit. But my book says that electrons move with constant velocity throughout the circuit, and both of ...
- 1,168
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280
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Does the number of electrons colliding in wire get double as the length of wire gets doubled?
Does the number of electrons colliding in a wire get doubled when length of wire is made twice with its area of cross-section remain constant.
My calculations for this are:-
For wire of length $L$ and ...