At what distance from wire '$B$' does the magnetic field become zero?

Discuss the similarities and differences between the Biot-Savart law and Coulomb's law.

Which of the following statements is true regarding magnetic lines of force?

Two long parallel wires carrying currents $I_1 = 4 \ A$ and $I_2 = 3 \ A$ in opposite directions are placed at a distance of $d = 5 \ cm$ from each other. $A$ point $P$ is at equidistance from both the wires such that the lines joining the point $P$ to the wires are perpendicular to each other. The magnitude of the magnetic field at point $P$ is ( $\mu_0 = 4 \pi \times 10^{-7} \ T \cdot m/A$ ).

$1 \ T = \dots \text{Gauss}$.

Describe the arrangement of iron filings sprinkled around a straight current-carrying wire.