Electrical, Circuits, Ohmslaw etc help

[whybeahero]

Electrical, Circuits, Ohmslaw etc help please

Homework Statement

Find the resistance of a copper conductor 300m in length if it has a CSA of 4mm2. The resistivity of copper is 1.72 x 10^-8m.

Homework Equations

This is all the information I have gotten from my teacher and i was wondering if anybody here can show me the formula and the answers to the questions.

The Attempt at a Solution

I would probably do something like 1.72 x 10^-8 X 200 or something i got no clue even for the other questions.

 

[Mr.A.Gibson]

You need to use the resistivity formula, should easily be able to look it up.

Make sure you use the units of the CSA correctly.

 

[whybeahero]

Ye the thing is I have no clue on how to work that out, or what that means lol the teacher didn't explain it on how to calculate it or anything, so can you show me how to work it out please.

 

[Redbelly98]

Homework Statement

Find the resistance of a copper conductor 300m in length if it has a CSA of 4mm2. The resistivity of copper is 1.72 x 10^-8m.

Homework Equations

This is all the information I have gotten from my teacher and i was wondering if anybody here can show me the formula and the answers to the questions.

The Attempt at a Solution

I would probably do something like 1.72 x 10^-8 X 200 or something i got no clue even for the other questions.

In the future, please post separate questions as separate threads.

For question #1: there is a formula for combining multiple resistors in series, to get the total resistance R_T. Check your textbook or class lecture notes, it is a standard formula that any introductory physics textbook will have.

 

[SammyS]

Homework Statement

Find the resistance of a copper conductor 300m in length if it has a CSA of 4mm2. The resistivity of copper is 1.72 x 10^-8m.
...

Has your teacher every written something like the following? Maybe it's in your textbook.

$$R=\frac{\,\rho\,\ell}{A}\ ,$$ where ρ is the resistivity and A is the cross-sectional area ?


.

 

[ehild]

Homework Statement

Find the resistance of a copper conductor 300m in length if it has a CSA of 4mm2. The resistivity of copper is 1.72 x 10^-8 Ωm.

Ohm (Ω) is the unit of resistance (R). Resistivity (ρ) is the resistance of a rod of 1 m length and 1 m² cross section. The resistance is directly proportional to the length and inversely proportional to the cross sectional area (A).

R=ρl/A.

Calculate the resistance of that cooper wire. ρ=1.72 x 10^-8 Ωm. You have to plug in the given data, but first transform the area from mm² to m². Go ahead.

ehild