Recent questions in Electric current

Ohm's law
Answered

linziboobeary1o8p
2022-05-18

Ohm's law
Answered

Brody Collins
2022-05-18

Resistivity
Answered

pevljivuaosyc
2022-05-18

${A}_{Au}=197g/mole$

and of copper

${A}_{Cu}=63.5g/mole$

The specific resistivity of gold is

$\rho =22.8n\mathrm{\Omega}m$

and the Nordheim coefficient is

$C=450n\mathrm{\Omega}m$

Then by the Nordheim rule we have that the resistivity of this alloy is given as

$\rho ={\rho}_{Au}+CX(1-X)$

where X=0.1, and represents the percentage of Copper in the alloy. Using the above I got that

$\rho =63.3n\mathrm{\Omega}m$

, but data shows that the actual resistivity is $\rho =108n\mathrm{\Omega}m$. What about X? Is it the percentage of atoms in the alloy, or is it the percentage of mass in the alloy?

Resistivity
Answered

Jordon Haley
2022-05-18

${a}^{2}+{b}^{2}+{c}^{2}+3(ab+bc+ca)\le \frac{1}{2}(\sqrt{a}+\sqrt{b}+\sqrt{c})(a+b)(b+c)(c+a).$

On atypical inequality (a smaller amount than a product) that resisted my attempts to prove it.

Resistivity
Answered

quorums15lep
2022-05-17

${R}_{H}=\frac{{E}_{y}}{{j}_{x}{B}_{z}}.$

Always as ${R}_{H}$. I am currious as to how to use this coefficient? Is it the y-direction resistance/resistivity (it is very close to the general resistivity from Ohm's law $\rho =E/j$)? Then I should be able to find it by ${R}_{H}={V}_{y}/{I}_{y}$ (or ${R}_{H}={E}_{y}/{j}_{y}$).

or is it simply defined as this as a proportionality constant (it does indeed look good with the three factors combined around one constant) and not an actual physical quantity?

Ohm's law
Answered

Brooklynn Hubbard
2022-05-17

Resistivity
Answered

Daphne Haney
2022-05-15

Resistivity
Answered

Jazlyn Raymond
2022-05-15

$\begin{array}{rl}R& =\rho \frac{L}{A}\\ I& =neA{v}_{d}\\ \mathrm{\Delta}V& =IR\\ {v}_{d}& =\frac{\mathrm{\Delta}V}{\rho Lne}\end{array}$

The resistivity does not change, neither does the length of the resistor nor the term ne but the resistance does change as well as the current, so the area is eliminated from the expression. I wonder if the drift velocity would be the same after increasing the diameter or if my derivation is wrong.

Resistivity
Answered

Nubydayclellaumvcd
2022-05-14

Suppose we have a projectile of mass m that impacts a material with velocity ${v}_{0}$. As it travels through the material it is subject to the resistive force $F=\alpha {v}^{2}+\beta $. How can I determine $v(t)$, the velocity of the projectile at time t where t=0 is the impact time, and $v(p)$, the velocity of the projectile when it reaches a penetration depth of p?

This question addresses v(t) for an exclusively quadratic resistive force ($\beta =0$), but is there a more general formula for when there is a constant component?

Resistivity
Answered

Yasmine Larson
2022-05-14

$R={R}_{0}\ast (1+\alpha (T-{T}_{0}))$

Where ${R}_{0}$ and ${T}_{0}$ are the reference resistance and temperature.

Is it then safe to say that:

$\rho ={\rho}_{0}\ast (1+\alpha (T-{T}_{0}))$

(where ${\rho}_{0}$ is the reference resistivity)?

Resistivity
Answered

Blaine Stein
2022-05-14

Resistivity
Answered

syaoronsangelhwc17
2022-05-14

Resistivity
Answered

vilitatelp014
2022-05-14

Resistivity
Answered

Osmarq5ltp
2022-05-14

Resistivity
Answered

Logan Lamb
2022-05-13

$R=\frac{\rho L}{A}$

However what is the volume resistivity of materials like copper and aluminium for instance? How do we calculate the volume resistivity of materials, because this was confusing when I read the site:

Method of calculating eddy currents of a conductor, is this correct?

Where there is the answer given by Floris states the equation:

$F=\frac{v\cdot {B}^{2}\cdot A}{\rho /t}$

Where $\rho $ is given to be the volume resisitivity.

My question:

how do we measure the volume resistivity of a material for example aluminium?

what happens if the thickness of the material changes?

Ohm's law
Answered

lurtzslikgtgjd
2022-05-13

The practical use of the electric current problems is met basically everywhere even if you are not majoring in Engineering. Take an example of data programming and the use of safety (data transfer) questions when the data is being transferred from place to place via cloud storage solutions. The same is related to automation and logistics where the electric current equation will help to calculate the limitations and the available resources. See some answers to the questions dealing with the electricity principles to get a better idea of how it works and compare the existing solutions to your task objectives!