All Questions
171
questions
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
181
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
99
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
77
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
280
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
122
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 ...
- 8,220
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 ...
