$A$ long wire carries a steady current. It is bent into a circle of one turn and the magnetic field at the centre of the coil is $B$. It is then bent into a circular loop of $n$ turns. The magnetic field at the centre of the coil for the same current will be

The magnetic field at the centre of a current-carrying circular coil is

Two concentric coils each of radius equal to $2\pi \, cm$ are placed at right angles to each other. $3 \, A$ and $4 \, A$ are the currents flowing in each coil respectively. The magnetic induction in $Wb/m^2$ at the centre of the coils will be $(\mu_0 = 4\pi \times 10^{-7} \, Wb/A \cdot m)$.

One of the two identical conducting wires of length $L$ is bent in the form of a circular loop and the other one into a circular coil of $N$ identical turns. If the same current $i$ is passed in both,the ratio of the magnetic field at the center of the loop $(B_L)$ to that at the center of the coil $(B_C)$,i.e.,$\frac{B_L}{B_C}$ will be:

The figure shows a square loop $ABCD$ with edge length $a$. The resistance of the wire $ABC$ is $r$ and that of $ADC$ is $2r$. The value of the magnetic field at the centre of the loop is:

Two parallel wires of equal lengths are separated by a distance of $3 \ m$ from each other. The currents flowing through the $1^{\text{st}}$ and $2^{\text{nd}}$ wires are $3 \ A$ and $4.5 \ A$ respectively in opposite directions. Find the resultant magnetic field at the midpoint between the wires $(\mu_0 = \text{permeability of free space})$.