Question 5.11: An overhead electrical power transmission line carries a cur......

Basic Electrical and Electronics Engineering [1015987]

An overhead electrical power transmission line carries a current of 100A. The direction of current flow through the line is from the West to the East direction. What is the direction of the magnetic field produced and what is its value 1 m below the overhead line?

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The magnitude of the magnetic field, B is expressed as

B=\frac{\mu_0 I}{2 \pi r}

Substituting values of $\mu_0 \text {, I, and } r \text { as } 4 \pi \times 10^{-7}, 100 \mathrm{~A}$ and 1m, respectively,

B=\frac{4 \pi \times 10^{-7} \times 100}{2 \pi \times 1}=20 \times 10^{-6} \mathrm{~Wb} / \mathrm{m}^2=20 \times 10^{-6} \text { Tesla }

The field produced is at right angles to the length of the current-carrying conductor.

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