Question

Two thin long parallel wires separated by a distance $d$ carry a current of $I$ ampere in same direction. They will

• A. attract each other with a force of $\frac{\mu_{0} I^{2}}{2 \pi d}$
• B. repel each other with a force of $\frac{\mu_{0} I^{2}}{2 \pi d}$
• C. attract each other with a force of $\frac{\mu_{0} I^{2}}{2 \pi d^{2}}$
• D. repel each other with a force of $\frac{\mu_{0} I^{2}}{2 \pi d^{2}}$

Answer 1

Answer: (A)

Current flows in same direction.
$\therefore $ Wires attract each other and $\frac{F}{l}=\frac{\mu_{0} I^{2}}{2 \pi d}$