All Questions
172
questions
-4
votes
1
answer
71
views
Is my simplified explanation of Volts vs Current correct? [closed]
I was struggling to find any meaningful difference between Volts and Current, when studying the basics of Ohm's law.
The sentences explaining Potential Difference, between the negative and positive ...
- 117
5
votes
2
answers
135
views
What is the "closed circuit" of a bug swatter racket?
There are bug swatter racket that can kill fruit flies, mosquitos, or flies, if the insect touches the metal mesh.
However, when I look at the construction of the device, the metal mesh is all one ...
- 151
0
votes
1
answer
38
views
Ideal Superconductor connected to Zero Voltage
If an ideal superconductor was just left alone, with no potential difference, what would be the current flowing in it?
According to Ohm's Law, $V = IR$
Hence, if a superconductor of $0\Omega$ ...
0
votes
2
answers
54
views
Piece of iron instead of a proper fuse
In a video game Dying Light 2, there are those electrical boxes that you open and then "fix" by putting a piece of iron (I suppose). Assuming voltage $U$ is being produced and is supplied ...
- 291
0
votes
2
answers
185
views
Explanation of Potential Difference
My question is to verify if my thought process below is correct.
So in a circuit the charge will flow (the current). When the charge flows there is resistance which is the collisions of the charge ...
- 37
0
votes
3
answers
119
views
Why won't the bulb light? [closed]
Here's what the marking scheme says: "Capacitor gets charged first and acts as an insulator/blocks current".
However, electrons flow from negative to positive, so shouldn't the electrons ...
- 93
0
votes
3
answers
102
views
Potential drop against internal resistance of cells in combination
Suppose two cells of emf and internal resistance e1, r1 and e2, r2 respectively are connected in series. The negative electrode of 1st cell is connected to negative electrode of the second cell. Why ...
- 1
1
vote
3
answers
1k
views
Does current make the full return trip?
In an AC system, the neutral wire is said to provide a return path for the current back to it's source. Given that the current is said to be alternating back and forth, how does this work, does the ...
- 13
0
votes
1
answer
39
views
When using a screwdriver tester i am completing the circuit with 110v?
if i use a screwdriver tester, i am part of the circuit with 110v passing my body? isn't this dangerous?
- 3
0
votes
1
answer
78
views
"Why do power lines use high voltage?" Loss in power equal to Current*Voltage? [duplicate]
I define P is the average power. So $P=IV$ and $I=\frac{P}{V}$.
$P_{loss}$ I define to be the power loss, which is equal to $I^2R$.
Substituting for $I$, $P_{loss} = \frac {P^2R}{V^2}$
So I get that ...
- 93
1
vote
1
answer
49
views
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
votes
5
answers
4k
views
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
0
votes
2
answers
287
views
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 ...
1
vote
1
answer
123
views
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 ...
- 69
0
votes
3
answers
1k
views
How does current actually flow in a wire?
When I was in my school I was taught that the electric field due to the battery is along the wire (from $A \rightarrow B \rightarrow C \rightarrow D $) and these are responsible for electrons at each ...
- 8,230
12
votes
2
answers
2k
views
Which electrons kill you during electrocution?
I understand that there are three velocities in play in a circuit (I haven't studied Physics past high school so give me some rope)
v1: the velocity by which the electrical field propagates through ...
1
vote
1
answer
225
views
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
0
votes
1
answer
89
views
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
1
vote
3
answers
124
views
$I$ 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 ...
9
votes
5
answers
3k
views
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 ...
- 275
1
vote
1
answer
2k
views
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 ...
-1
votes
2
answers
203
views
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 ...
- 962
7
votes
5
answers
3k
views
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
0
votes
1
answer
43
views
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
1
vote
2
answers
259
views
Does a higher voltage always mean a higher electric field strength?
In a step-up transformer, the output voltage is higher than the input voltage, while the output current is lower than the input current. Basically, since P = VI is conserved, the current has to ...
- 337
0
votes
1
answer
183
views
EMF of source depends on the charge and the path then what do we mean when we say EMF of a source is $\epsilon$?
EMF of an EMF source (a battery for example) is defined as the work done by the non-conservative force(s) on charged particles as it passes through the terminals of the source divided by the charge of ...
- 480
0
votes
2
answers
597
views
Electric potential and kinetic energy in any flowing charge
We just started with electricity in school(grade 10) and I have some confusions regarding electric potential.
According to my book,
The potential at a point is defined as the amount of work done per ...
- 1,168
20
votes
4
answers
5k
views
Are the "bird sitting on a live wire" answers wrong?
Long ago, my high school teacher wrote the popular question on board,
"Why doesn't a bird sitting on a live wire get electrocuted?"
He gave us four options (I don't remember all of them) ...
- 1,441
21
votes
8
answers
13k
views
Why do we reduce only current to prevent power loss? Why not voltage?
In power transmission lines current is kept low and voltage is kept high to reduce the power loss. This is because $P = I^{2}R$ and $P = VI$. In order to reduce power loss we have to reduce $I$ since $...
- 335
1
vote
4
answers
1k
views
Current vs voltage in high voltage transmission lines
I know this question has been answered many times, but sadly I'm still not quite sure I get it.
Here's my interpretation, please correct me at any point:
We have some source. There's various ways to ...
- 135