Question

Three straight parallel current carrying conductors are shown in the figure. The force experienced by the middle conductor of length $25cm$ is :

• A. Zero
• B. $9\times {10}^{-4}N$ toward left
• C. $6\times {10}^{-4}N$ toward left
• D. $3\times {10}^{-4}N$ toward right

Answer 1

The correct option is D $3\times {10}^{-4}N$ toward right

Force due to the first wire on the middle wire is,
$F_1=\frac{{\mu }_{o}I{I}_1}{6\pi }\times 25=\frac{2500{\mu }_o}{2\pi }$

Force due to the second wire on the middle wire is,
$F_2=\frac{{\mu }_{o}I{I}_2}{10\pi }\times 25=\frac{1000{\mu }_o}{2\pi }$

Net Force $F=F_1-F_2=\frac{1500{\mu }_o}{2\pi }=3\times {10}^{-4}N$ towards right