(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Calculate the resistance of a strand of aluminium wire of diameter 4.0mm and length 1.0m, given its resistivity is 2.5*10^-8 Ωm. What would be the resistance per meter of 50 strands of this wire, using the strands in parallel as a cable?

2. Relevant equations

∏d^2/4 for area

ρ=RA/L,

Where ρ = Given resistivity

R= Resistance

A= Cross sectional Area

L= Length

3. The attempt at a solution

4.00mm Diameter → 4*10^-3 Converted to Meters

Length = 1m

Resistivity = 2.5*10^-8 Ωm

So I found out the Area using ∏d^2/4;∏*(4*10^-3)/4 which = 1.26*10^-5 m^2

Then I used the formula

ρ=RA/L,

rearranging for R,

ρL/A = R

and subbing in the values;

2.5*10^-8 * 1 /1.26*10^-5

which gives an answer of 1.989*10^-3 Ωm^-1

thus i multiplied it by 50 which gives a final answer of 0.09945

However my answer differs from the answer of the book which is given as 4.99Ωm^-1

Thanks for any help!

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# Homework Help: Electricity; Calculating Resistance.

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