Question

Two parallel wires $2 \,m$ apart carry currents of $2\, A$ and $5 \,A $ respectively in same direction, the force per unit length acting between these two wires is

• A. $2 \times 10^{-6}N \, m^{-1}$
• B. $3 \times 10^{-6}\,N\, m^{-1}$
• C. $1 \times 10^{6} \, N\, m^{-1}$
• D. $4 \times 10^{-6}\, N\, m^{-1}$

Answer 1

Answer: (C)

Given, $I_{1}=2A$,
$I_{2}=5A$,
$r=2\,m$
$\therefore f=\frac{\mu_{0}}{4\pi}\frac{2I_{1}I_{2}}{r}=10^{-7}\times\frac{2\times2\times5}{2}$
$=1\times10^{-6}\,N\,m^{-1}$