Question

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

$[$1 Mark$]$

• A. $\sqrt{2}$ times magnitude of the magnetic field produced due to each wire.
• B. half of the magnitude of the magnetic field produced due to each wire.
• C. twice the magnitude of the magnetic field produced due to each wire.
• D. zero

Answer 1

The correct option is D zero


The magnetic field due to long wire carrying current is given by
$B=\frac{{\mu }_{0}i}{2\pi d}$
$\to$ The direction of magnetic field can be found by using right hand thumb rule.
$\to$ Place the thumb along the direction of current and curling fingers represents the direction of magnetic field.
$\therefore$ At mid point between the wires, the magnetic field due to both wires is equal in magnitude but in direction.
So, net magnetic field at midpoint is zero.