All Questions
29
questions
1
vote
1
answer
113
views
Derivation and theory for $I = kV^n$ [closed]
I performed an experiment in college to study the nature of a filament of a lamp, determine $k$ and $n$ in the relation mentioned, and study the variation of wattage of a lamp. I assume ohm's law is ...
- 33
0
votes
2
answers
78
views
Why doesn't charge accumulate in a loop?
When learning about electromagnetism at my university, electricity flow is generally shown as a conductor with a high potential at one end and a low potential at the other and thus charges flowing ...
- 3
0
votes
1
answer
42
views
Do electrons move faster towards the end of a circuit?
As 1 coulomb electrons go through 1 volt of potential difference, they gain 1 joule of energy. So in s series circuit, do electrons move faster towards the end of the circuit where they went though a ...
0
votes
4
answers
84
views
About electric field and electric potential
We know that electric potential is the negative of work done by electric field in moving a unit charge from infinity to that place.
This statement shows that electric field causes a potential ...
- 105
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 ...
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
2
votes
4
answers
1k
views
Why is current density in a conductor of uniform cross sectional area constant at all points?
According to what I was taught, if current was dispersed “uniformly,” current density would remain constant.
So, in a conductor, the 'current density should be the same at all points.' But, given that ...
- 444
0
votes
2
answers
393
views
Potential difference across two points in a current-carrying wire [duplicate]
I have had this doubt for quite a while and I have tried reading answers to similar questions but I'm still not sure.
If I connect a voltmeter at A and B, what would be the reading? Is it going to be ...
user287374
3
votes
1
answer
5k
views
What is the difference between electric spark and electric arc?
In my student book they separate these two and indicate that sparks need high voltage to occur while arcs need low voltage with normal or low pressure and electric arcs CAN come with heat and bright ...
- 59
1
vote
1
answer
108
views
What is the point of using an inverting amplifier in a circuit? [closed]
This may be a simple question to most of you, but I'm having trouble understanding the concept behind the use of an inverting amplifier.
What is the purpose of using an op amp in an inverting ...
- 113
0
votes
1
answer
46
views
Question on electricity and the basics of potential difference
I am having some difficulty understanding how batteries work. I don't quite understand what exactly potential difference is. My textbook says it is the work done per unit charge to move an electron, ...
- 169
2
votes
3
answers
146
views
Flow of charges
I saw this question which asks for the condition for flow of electricity through the conductor i know that electricity will flow only when there is a potential difference achieved between the ...
- 1,200
0
votes
0
answers
122
views
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. ($\...
- 155
0
votes
0
answers
147
views
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 ...
- 2,517
0
votes
3
answers
561
views
Electric field and current
When we provide a potential difference in a circuit it does nothing more than provide an electric field to the conductor,When an electric field is provided in a conductor the free electrons move to ...
- 307
1
vote
2
answers
1k
views
Two charged spheres connected by a wire
I have a few doubts about this problem. So we have two charged spheres of radius $r_1$ and $r_2$, one is initially charged with a charge $Q$, while the other one is initially without charge. The ...
0
votes
2
answers
469
views
Direction of current flow in circuit with multiple cells
As the point $A$ is earthed we know that its potential is zero, same is true for point $B$. Due to the cell between $B$ and $C$ we can say that potential at $C$ is $-3V$. So the potential at point D ...
0
votes
1
answer
163
views
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 ...
2
votes
1
answer
1k
views
Can electric potential be discontinuous?
I am studying the following problem, which is 9.11 of "Modern Electrodynamics" by Zangwill.
The idea is that you have a wire attached to a perfectly conducting sphere (radius $a$) buried into the ...
- 1,544
1
vote
1
answer
1k
views
How is PD = EMF for an open circuit?
For an open circuit, $V = E - Ir$. People say since there is no current flowing, $V$ is equal to $E$. However $V = IR$, where $R$ is the external resistance, that doesn't exist either so how can ...
5
votes
1
answer
3k
views
Can conductor be charged?
I have a copper conductor. For a while, I apply a voltage of $12kV$ DC from a source. After removing the source, will the conductor stay charged from the source if is not earthed? Will it discharge ...
- 185
-4
votes
3
answers
182
views
Doesn't any massive conductor look like "ground" to an AC supply?
I've been puzzling over this excellent answer to the perennial "Why don't I get shocked by a hot wire if I'm not grounded?" question. The orders of magnitude just don't seem right for two reasons:
...
- 924
4
votes
1
answer
223
views
At what distance is lightning dangerous for someone lying down?
My 8 yo child told me that they learned at school that they should lay down flat on the ground in case of lightning. I told him that the more correct position is crouching down with feet together, but ...
- 516
0
votes
1
answer
175
views
How do the electrons know the route? [duplicate]
I've learnt in classroom that the requirements for electrical current to flow in a circuit are as follows:
there must be a closed conducting path between negative and positive terminals
there must be ...
- 13k
1
vote
5
answers
2k
views
Field inside a wire?
This answer gives a great explanation of why the field inside a wire connected to a battery must be equal at all points: Why doesn't the electric field inside a wire in a circuit fall off with ...
user41086
5
votes
2
answers
503
views
How does current flow in a irregularly shaped heterogeneous resistor?
The motivation for my question is understanding how electricity gets through your skin as opposed to running along it, and how the presence of things like water on the skin affect the relative ...
user24082
2
votes
1
answer
2k
views
Why should a battery not give current in order to measure EMF?
Emf is the "potential difference (PD) across the terminals of a battery when it is giving no current to the circuit."
What does "when it is giving no current mean"? Will the PD across the terminals ...
- 1,159
2
votes
2
answers
422
views
Fundamentality of voltage to current
From Ohm's Law :
Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points.
I would like to know if ...
- 950
1
vote
1
answer
11k
views
Current against the inverse of resistance graph, $I = V/R +c$
If I have a plot of current ($y$ axis) against 1/Resistance ($x$ axis).
The circuit it is measured from is a simply 2 resistors connected in parallel to battery, where the potential across the ...
- 6,927