Question

Two long parallel copper wires carry currents of $5A$ each in opposite directions. If the wires are separated by a distance of $0.5m,$ then the force between the two wires is

• A. $10^{- 5}N,$ attractive
• B. $10^{- 5}N$ repulsive
• C. $2\times 10^{- 5}N,$ attractive
• D. $2\times 10^{- 5}N,$ repulsive

Answer 1

Answer: (B)

$F=10^{- 7}\frac{2 i_{1} i_{2}}{g}=10^{- 7}\times \frac{2 \times 5 \times 5}{0 . 5}=10^{- 5}N$ (repulsive)