Two very long straight conductors (wires) are set parallel to each other. Each carries a current ' I ' in the same direction and the separation between them is ' 2r '. The intensity of the magnetic field at point ' P ' (as shown in the figure) ( ₀= permeability of free space) is

Step-by-step solution

Magnetic field at point P The total magnetic field is found using superposition of fields from each wire. For a long straight wire carrying current I , the field magnitude at distance d is B = ₀ I 2 d . The left wire is at distance d₁ = 3r from point P. Using the right-hand rule, the field B₁ points into the page with magnitude B₁ = ₀ I 2 (3r) = ₀ I 6 r . The right wire is at distance d₂ = r from point P. Similarly, B₂ points into the page with B₂ = ₀ I 2 r . Both fields are in the same direction, so their magnitud