question_answer

Two long straight wires are set parallel to each other at separation rand each carries a current in the same direction. The strength of the magnetic field at any point midway between the two wires is

A)  \[\frac{{{\mu }_{0}}i}{\pi r}\]                                    

B) \[\frac{2{{\mu }_{0}}i}{\pi r}\]

C) \[\frac{{{\mu }_{0}}i}{2\pi r}\]                   

D)         zero

Correct Answer: D

Solution :

\[{{B}_{1}}=\frac{{{\mu }_{0}}i}{2\pi \left( \frac{r}{2} \right)}\] \[{{B}_{2}}=\frac{{{\mu }_{0}}i}{2\pi \left( \frac{r}{2} \right)}\]                 So,          \[{{B}_{net}}=0\]