Question

Figure shows two long wires carrying equal currents $I_1$ and $I_2$ flowing in opposite directions. Which of the arrows labeled $A,B,C$ and $D$ correctly represents the direction of the magnetic field due to the wires at a point located at an equal distance $d$ from each wire?

• A. $A$
• B. $B$
• C. $C$
• D. $D$

Answer 1

The correct option is B $B$

Magnitude of magnetic field at the given distance d from the wires is same because:

$B_1=B_2=\frac{{\mu }_o{I}_1}{2\pi d}$

Net magnetic field, $B=B_h+B_v$

where horizontal component, $B_h=B_1\cos 30-B_2\cos 30=0$

vertical component, $B_v=B_1\sin 30+B_2\sin 30=B_1$ upwards