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Question 26.31: An electrical cable consists of 125 strands of fine wire, ea......

An electrical cable consists of 125 strands of fine wire, each having 2.65 μΩ resistance. The same potential difference is applied between the ends of all the strands and results in a total current of 0.750 A. (a) What is the current in each strand? (b) What is the applied potential difference? (c) What is the resistance of the cable?

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(a) The current in each strand is i=0.750 \,A / 125=6.00 \times 10^{-3} \,A \text {. }

(b) The potential difference is V=i R=\left(6.00 \times 10^{-3}\, A \right)\left(2.65 \times 10^{-6} \Omega\right)=1.59 \times 10^{-8} \,V .

(c) The resistance is R_{\text {total }}=2.65 \times 10^{-6}\, \Omega / 125=2.12 \times 10^{-8}\, \Omega .

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