Module 3 : MAGNETIC FIELD
Lecture 15 : Biot- Savarts' Law
Example 5
 

Field due to a straight wire carrying current

The direction of the field at P due to a current element $\vec{dl}$is along $\vec{dl}\times\vec r$, which is a vector normal to the page (figure on the left) and coming out of it.

\includegraphics{fig3.17.eps}

We have,

\begin{displaymath}\frac{\vec{dl}\times\hat r}{r^2} = \frac{\mid dl\sin\theta\mid}{r^2}\hat k\end{displaymath}

where the plane of the figure is taken as the x-y plane and the direction of outward normal is parallel to z-axis. If $a$be the distance of the oint P from the wire,

         Back                                                                                                                             Next