Two parallel conducting wires of equal length are placed distance d apart carry current I₁ and I₂ respectively in opposite directions. The resultant magnetic field at the midpoint of the distance between both the wires is

Step-by-step solution

Field due to a current-carrying long wire is given by B= ₀ I 2 r The field at the midpoint between the two wires are in the same direction and hence get added. The distance of the midpoint r= d 2 aligned & B=B₁+B₂= ₀ I₁ 2 ( d 2 ) + ₀ I₂ 2 ( d 2 ) & = ₀ (I₁+I₂ ) 2 ( d 2 ) aligned