All Questions
38
questions
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
0
answers
159
views
Electrical resistivity calculation of a cylindrical material
I have a copper rod, its diameter is 13mm, and its height is 13mm. I want to check its electrical resistivity. I have tools to give this copper a constant current by two points (the two black dots in ...
- 111
0
votes
1
answer
61
views
The equivalent resistance of the networks shown is [closed]
I solved the by taking resistance at the right side as in series but got ans as 5R/13 but the is 5R/11
- 21
1
vote
2
answers
4k
views
Charge flowing through switch when it is closed [closed]
The problem that I'm having is that the initial charges would have been 300 and 600 microcoulomb on the 3 and 6 microfarad capacitors respectively. But when the switch is closed there's some charge ...
- 21
1
vote
2
answers
102
views
Charges/Current at a junction [closed]
How is current distributed into two or more wires joined to an original wire at a junction? Is there a rule that allows us to find out the current in a single wire if the currents in the rest of the ...
- 161
1
vote
3
answers
928
views
How to find the current if both positive and negative charges are moving?
A gas is connected to a copper conductor. In the gas, +6C of charge move to the left every second, and -6C of charge move to the right every second. What is the current in the copper conductor, and ...
- 254
1
vote
0
answers
48
views
Voltage difference vs number of electrons [duplicate]
When we say a battery has voltage difference, can we deduce the difference in the number of electrons at the two terminals? What does it mean to say there exists a voltage difference?
- 149
1
vote
1
answer
1k
views
Angle measurement in deriving the magnetic field of a infinitely long solenoid
I'm facing a doubt in the derivation of the magnetic field inside an infinitly long solenoid of radius $R$.
To derive $B$ all the loops in the solenoid are considered: in a lenght $dx$ there are $n\,...
- 2,617
0
votes
1
answer
127
views
How to use general expression of force between two circuits to find the force between two wires?
The general expression of the force between two circuits $1$ and $2$ with currents $i_1$ and $i_2$ and with line elements $\bf{dl_1}$ and $\bf{dl_2}$ (infinitesimal vectors pointing in the direction ...
- 2,617
0
votes
1
answer
771
views
Condition for Maximum Power in the circuit [duplicate]
Maximum Power is transferred to a load when load resistance is equal to internal resistance of source.
I want to know How ?
If I consider a source with internal resistance 'R' ,connected with ...
- 293
3
votes
2
answers
875
views
Electric field outside wire with stationary current
Consider a conductor of arbitrary structure where a stationary current flow, that is
$$\nabla \cdot \vec{j}=0$$
I did not find on textbook clear explanations on two facts:
How is the electric ...
- 2,617
2
votes
2
answers
2k
views
Faraday's law in circuits with multiple loops and different magnetic fields
I'm confused about the application of Faraday's Law in to situations with a circuit made of two loops that enclose two different changing magnetic fluxes.
Which of the two is correct?
The emf in each ...
- 2,617
1
vote
1
answer
416
views
How to predict length of conductor?
A long round conductor of cross sectional area $S$ is made of material whose resistivity depends only on a distance $r$ from axis of the conductor $\rho=\frac{\alpha}{r^2}$, where $\alpha $ is ...
- 209
1
vote
1
answer
945
views
Resistivity - Resistance of a wire wounded closely together
Here is the question I'm facing,
The cross sectional area of a bare wire is a square of area 1.00mm^2. A 10.0m, length of this wire is wound close together on a wooden cylinder so that neighbouring ...
- 15
1
vote
2
answers
16k
views
Why does internal resistance increase as current decreases?
Our class conducted and experiment to investigate internal resistance and terminal pd, using a cell, fixed resistor and variable resistor. The results were as follows:
As the resistance of the ...
- 361