Do two magnetic field lines intersect each other? Why?

$A$ straight conductor of length $32 \,cm$ carries a current of $30 \,A$. Magnetic induction at a point in air at a perpendicular distance of $12 \,cm$ from the mid-point of the conductor is (in $G$)

$A$ long curved conductor carries a current $I$. $A$ small current element of length $dl$ on the wire induces a magnetic field at a point away from the current element. If the position vector between the current element and the point is $\vec{r}$,making an angle $\theta$ with the current element,then the induced magnetic field density $d\vec{B}$ at the point is $(\mu_0 = \text{permeability of free space})$:

Two concentric circular coils of $10$ turns each are situated in the same plane. Their radii are $20 \, cm$ and $40 \, cm$ and they carry respectively $0.2 \, A$ and $0.3 \, A$ current in opposite directions. The magnetic field at the centre is $(\mu_0 = 4 \pi \times 10^{-7} \, T \cdot m/A)$

$A$ straight wire carrying a current of $12 \,A$ is bent into a semi-circular arc of radius $2 \,cm$ as shown in the figure. Then the magnetic field due to the straight segments at the centre of the arc is

$A$ wire of length $L = 1 \ m$ carries a constant current $I$. The wire is bent to form a single circular loop of radius $R$. The magnetic field at the centre of this loop is $B$. If the same wire is now bent to form a circular loop with $n = 4$ turns,what will be the magnetic field $B'$ at the centre of this new loop?