Question

Through two parallel wires A and B, 10A and 2A of currents are passed respectively in opposite directions. If the wire A is infinitely long and the length of the wire B is 2m, then force on the conductor B, which is situated at 10 cm distance from A, will be

• A. $8\times {10}^{-7}N$
• B. $8\times {10}^{-5}N$
• C. $4\times {10}^{-7}N$
• D. $4\times {10}^{-5}N$

Answer 1

Answer: (B)

$8\times {10}^{-5}N$

$F=\frac{{\mu }_0}{4\pi }\frac{2I_1{I}_2}{r}\times l$
$=\frac{{10}^{-7}\times 2\times 10\times 2}{0.1}\times 2$
$=8\times {10}^{-5}N$