Same current i is flowing in the three infinitely long wires along positive x-,y- and z-directions. The magnetic filed at a point (0,0,-a) would be

Options

A. `(mu_(0)i)/(2pia)(hatj-hat i)`
B. `(mu_(0)i)/(2pi a)(hat j + hat i)`
C. `(mu_(0)i)/(pia)(hatj - hat i)`
D. `(mu_(0)i)/(2pia)(hat I + hat j + hat k)`

Answer

A

Explanation

Magnetic field in diffeent direction are in the below `B_(y) =(mu_(0)i(-hati))/(2pia)` and `B_(x)=(mu_(0)ihatj)/(2pia)`
Magnetic field `B_(net)=B_(x)+B_(y)`
`=(mu_(0)i)/(2pia)(hatj - hat i)`