Two parallel very long straight wires carrying current of 5 A each are kept at a separation of 1 m. If the currents are in the same direction, the force per unit length between them is N m⁻¹. (μ₀=4π×10⁻⁷ SI)

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(2) 5×10⁻⁶, attractive. Given: I₁=I₂=5 A, d=1 m, currents parallel. Idea: each wire sits in the other's field B=(μ₀I)/(2π d) and feels F=BIℓ, so F/ℓ=(μ₀I₁I₂)/(2π d). (μ₀)/(2π)=(4π×10⁻⁷)/(2π)=2×10⁻⁷. F/ℓ=2×10⁻⁷×(5×5)/1=5×10⁻⁶ N m⁻¹. Parallel currents in the same direction attract, so the force is attractive.

Two parallel very long straight wires carrying current of 5 A each are kept at a separation of 1 m. If the currents are in the same direction, the force per unit length between them is ______ N m⁻¹. (μ₀=4π×10⁻⁷ SI)

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