If a copper wire is steched to make 0.1% thinner, then what is the percentage increase in resistance

Asked by tangocharliee | 11th Nov, 2009, 02:25: PM

Expert Answer:

Streching elongates the wire, while simultaneously making it thinner.

Initial Volume = Final Volume

AiLi = AfLf

AiLi  = 0.999AiLf

Lf = Li/0.999

Rf = ρLf/Af = ρLi/(0.9992xAi)

Rf = 1.002ρLi/Ai = 1.002Ri

The resistance increases by 0.2%.

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TopperLearning.  

Answered by  | 11th Nov, 2009, 04:01: PM

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