Question

A long straight conductor having a radius of cross-section of $1cm$ carried a steady current of $5A$. The current is uniformly distributed over its cross-section. Find the value of $B$ at a point at a distance of $1.5cm$ from its surface. $[{\mu }_O=4\pi \times {10}^{-7}Wb/Am]$

Answer 1

$B=\frac{{\mu }_{0}I{r}^2}{4\pi {(5^2+{1.5}^2)}^{3/2}}=\frac{{10}^{-5}\pi }{4\pi {\left(27.25\right)}^{3/2}}=\frac{{10}^{-5}}{4\times 140.25}=0.0017\times {10}^{-5}$