Question

the resistance of 1m long alluminium wire is 8n .if we reduce the legth of the wire 80cm ,what will its resistance be?
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Answer 1

Explanation:

R=26 Ω

l=1m

d−0.3mm

r=2d=20.3×10−3=0.15×10−3m

A=πr2=3.14×(0.15×10−3)2=0.071×10−6m2

R=AρL

or ρ=lRA=126×0.071×10−6=1.84×10−6Ωm