Question

Two very long, straight wires carrying currents as shown in figure. Find all locations where the net magnetic field is zero.

• A. $y=\sqrt{2}x$
• B. $y=x$
• C. $y=-x$
• D. $y=-\left(x/2\right)$

Answer 1

The correct option is C $y=-x$

Along the dashed line, $\overrightarrow{B_1}$ and $\overrightarrow{B_2}$ are in opposite directions. If the line has slope $-1.00$,

then $r_1=r_2$ and $B_1=B_2$. So, $B_{net}=0$
Hence, slope of the line dashed line is -1.
$\Rightarrow y=-x$ as the line passes through the origin making intercept zero.