question_answer

Two long straight wires are set parallel to each other. Each carries a current; in the same direction and the separation between them is 2r. The intensity of the magnetic field midway between them is     

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

B)  \[\frac{4{{\mu }_{0i}}}{r}\]

C)  zero                     

D)         \[\frac{{{\mu }_{0i}}}{4r}\]

Correct Answer: C

Solution :

The magnetic field at point\[P\]                 \[{{B}_{net}}={{B}_{1}}-{{B}_{2}}\] Since,    \[|{{B}_{1}}|\,\,=\,\,|{{B}_{2}}|\] So,        \[{{B}_{net}}=0(zero)\]