Question

Two long parallel wires are $30 \, cm$ apart carrying currents $10 \, A$ and $15 \, A$ respectively in the same direction. The force acting over a length of $5 \, m$ of the wires is

• A. $5\times 10^{- 4 \, }N$ , (attraction)
• B. $1\times 10^{- 4}N$ , (attraction)
• C. $5\times 10^{- 4}N$ , (repulsion)
• D. $1\times 10^{- 4}N$ , (repulsion)

Answer 1

Answer: (A)

Force acting between two parallel wire
$F=\frac{\mu _{0} i_{1} i_{2}}{2 \pi r}l$
$F=\frac{\left(2 \times 1 0^{- 7}\right) \left(10\right) \left(15\right)}{0.3}\times 5$
$F=5\times 10^{- 4} \, N$