Question

Two parallel conductors A and B separated by 5 cm carry electric current of 6 A and 2 A in the same direction. The point between A and B where the field is zero is at

• A. 0.25 cm from B
• B. 1 cm from B
• C. 1.25 cm from B
• D. 3.75 cm from B

Answer 1

The correct option is C 1.25 cm from B

Let point is at x distance away from B

So $B_1$ due to wire B$=\frac{{\mu }_0\times 2}{2\pi x}$

$B_2$ due to wire A$=\frac{{\mu }_0\times 6}{2\pi (5-x)}$

At Neutral point,

$B_1=B_2$

$\frac{2}{x}=\frac{6}{5-x}$

$10-2x=6x$

$x=\frac{10}{8}=\frac{5}{4}=1\cdot 25cm$