Question

A long straight wire in the horizontal plane carries a current of $50A$ in north to south direction. Given the magnitude and direction of $B$ at a point $2.5m$ east of the wire.

• A. $2\times {10}^{-6}T,$ south
• B. $3\times {10}^{-6}T,$ down
• C. $4\times {10}^{-6}T,$ up
• D. $6T$, north

Answer 1

The correct option is C $4\times {10}^{-6}T,$ up

$\begin{array}{c}B=\frac{\mu 2}{4Mr}\left(\sin \theta +\sin {\theta }_2\right)\\ \Rightarrow \frac{4M\times {10}^{-7}\times 500}{4M\times 25}\times 2\\ \Rightarrow 2\times {10}^{-6}\times 2T\\ \Rightarrow 4\times {10}^{-6}T,up\end{array}$

Hence,

option $C$ is correct answer.