Question

Two wires are held perpendicular to the plane of paper and are 5 m apart. The currents of 2.5 A and 5 A in same dir then, the magnetic field strength (B) point midway between the wires will be then

• A. $\frac{{\mu }_0}{4\pi }T$
• B. $\frac{{\mu }_0}{2\pi }T$
• C. $\frac{3{\mu }_0}{2\pi }T$
• D. $\frac{3{\mu }_0}{4\pi }T$

Answer 1

The correct option is A $\frac{{\mu }_0}{4\pi }T$

$B=B_1-B_2$

$\frac{{\mu }_0{i}_1}{2\pi r_1}-\frac{{\mu }_0{i}_2}{2\pi r_2}$

$atMidpointr=\frac{5}{2}=2.5um.$

$B=\frac{{\mu }_0}{2\pi }\left(\frac{i_1}{r}-\frac{i_2}{r}\right)$

$\frac{{\mu }_0}{2\pi }\left(\frac{5}{2.5}-\frac{2.5}{2.5}\right)$

$\frac{{\mu }_0}{2\pi }\left(2-1\right)=\frac{{\mu }_0}{2\pi }$