- #1
FlyingSpartan
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Homework Statement
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?
Homework Equations
∏d^2/4 for area
ρ=RA/L,
Where ρ = Given resistivity
R= Resistance
A= Cross sectional Area
L= Length
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!