Question

Three long, straight parallel wires carrying current, are arranged as shown in figure. The force experienced by a 25 cm length of wire C is

• A. ${10}^{-3}$ N
• B. $2.5\times {10}^{-3}$ N
• C. Zero
• D. $1.5\times {10}^{-3}$ N

Answer 1

The correct option is C Zero

Force on wire C due to wire D
$F_D={10}^{-7}\times \frac{2\times 30\times 10}{2\times {10}^{-2}}\times 25\times {10}^{-2}=5\times {10}^{-4}N.....$ (towards right)

Force on wire C due to wire G
$F_G={10}^{-7}\times \frac{2\times 20\times 10}{2\times {10}^{-2}}\times 25\times {10}^{-2}=5\times {10}^{-4}N.....$ (towards left)
$\Rightarrow$ Net force on wire C is $F_{net}=F_D-F_G=0$