Two infinitely long parallel wires carry equal current in same direction. The magnetic field at a mid point in between the two wires is

Options

A. `mu_(0)// 17`
B. `sqrt(3)mu_(0) // 2pi`
C. `mu_(0)// 2pi`
D. `3mu_(0)// 2pi `

Answer

C

Explanation

` = ( mu_(0))/(4pi) (2i_(2))/((r//2)) - (mu_(0))/(4u)(2i_(1))/((r//2)) = (mu_(0))/(4pi r) (4)/(r)(i_(2) -i_(1))`
`= (mu_(0))/(4pi) (4)/(5) (5-2.5)=(mu_(0))/(2pi)`