Which of the following is a vector quantity?

Two long parallel wires are separated by a distance of $2.50 \ cm$. The force per unit length that each wire exerts on the other is $4 \times 10^{-5} \ N \ m^{-1}$, and the wires repel each other. The current in one wire is $0.5 \ A$. What is the current in the second wire (in $A$)? (Take $\mu_0 = 4 \pi \times 10^{-7} \ S.I. \ \text{unit}$)

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) ($\mu_0=$ permeability of free space) is

Among the following,the unit of permeability is $NOT$ represented by

An infinitely long wire carrying current $I$ is along the $Y$-axis such that its one end is at point $A(0, b)$ while the wire extends up to $+\infty$. The magnitude of the magnetic field strength at point $(a, 0)$ is:

$A$ tightly wound $100$ turns coil of radius $10 \,cm$ carries a current of $7 \,A$. The magnitude of the magnetic field at the centre of the coil is (Take permeability of free space as $4 \pi \times 10^{-7} \,SI$ units):