A long straight wire with a circular cross-section having radius R, is carrying a steady current I. The current I is uniformly distributed across this cross-section. Then the variation of magnetic field due to current I with distance r (r < R) from its centre will be :
Solution
<p>$\int {\overline B \,.\,\overline {dl} = {\mu _0}{I_{in}}}$</p>
<p>$\Rightarrow B \times 2\pi r = {{{\mu _0}I} \over {\pi {R^2}}} \times \pi {r^2}$</p>
<p>$\Rightarrow B \propto r$</p>
About this question
Subject: Physics · Chapter: Magnetic Effects of Current · Topic: Biot-Savart Law
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