0
votes
2answers
259 views

Capacitors and resistor in series and in parallel [closed]

In this circuit, are $R_1$ and $C_1$ in parallel and $C_2$ and $R_2$ in series? I have think that the currents that flows trought $R_1$ isn't the same that flows trought $C_1$ so, $R_1$ and $C_1$ ...
0
votes
1answer
60 views

how to find the diameter of this fuse? [closed]

A fuse blows if the current exceeds 1.0 A. It is made of material that melts at a current density of 620A/cm2. What is the diameter of the wire, assumed to have a circular profile, in the fuse?
1
vote
1answer
304 views

Non-conservative Electric Field

I was watching this video from Walter Lewin and while watching these two videos, I noticed there is a "contradiction" in what he is doing. All links direct you exactly to where he begins, so you don't ...
10
votes
3answers
1k views

Is it possible to mathematically derive the formula for resistance?

Resistance is given by $\rho L/A$, where $\rho$ is the material constant, $L$ is the length, and $A$ is the area. Is there any way that this can be derived mathematically, or is the only way ...
-1
votes
4answers
977 views

Resistance between two points on a conducting surface

Suppose we have a cylindrical resistor, with resistance given by $R=\rho\cdot l/(\pi r^2)$ Let $d$ be the distance between two points in the interior of the resistor and let $r\gg d\gg l$. Ie. it is ...