Two long parallel wires are at a distance of 1 metre. Both

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Two long parallel wires are at a distance of 1 metre. Both of them carry one ampere of current. The force of attraction per unit length between the two wires is

1. 2 × 10^–7 N/m
2. 2 × 10^–8 N/m
3. 5 × 10^–8 N/m
4. 10^–7 N/m

Correct Option: A

F =	μ₀	×	2i₁i₂I	= 10^-7 ×	2 × 1 × 1 × 1	= 2 × 10^-7 N/m.
	4π		r		1

[This relates to the definition of ampere]