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 mid-way between them is
A) \[\frac{{{\mu }_{0}}i}{r}\]
B) \[\frac{4{{\mu }_{0}}i}{r}\]
C) zero
D) \[\frac{{{\mu }_{0}}i}{4r}\]
Correct Answer:
A
Solution :
At point P, \[{{B}_{net}}={{B}_{AB}}+{{B}_{CD}}\] \[=\frac{{{\mu }_{0}}i}{2r}+\frac{{{\mu }_{0}}i}{2r}\] \[=\frac{{{\mu }_{0}}i}{r}\]