If the strength of the magnetic field produced $10\,cm$ away from an infinitely long straight conductor is ${10^{ - 5}}\,Wb/m^2$,the value of the current flowing in the conductor will be........$A$.

$A$ circular loop of radius $r$ of conducting wire connected with a voltage source of zero internal resistance produces a magnetic field $B$ at its centre. If instead, a circular loop of radius $2r$, made of the same material and having the same cross-section, is connected to the same voltage source, what will be the magnetic field at its centre?

The intensity of the magnetic induction field at the centre of a single turn circular coil of radius $5 \,cm$ carrying a current of $0.9 \,A$ is:

Two parallel wires carry currents $i_1$ and $i_2$ $(i_1 > i_2)$. When the currents are in the same direction,the magnetic field at a point midway between the wires is $10 \, \mu T$. When the direction of $i_2$ is reversed,the magnetic field at that point becomes $30 \, \mu T$. What is the ratio $\frac{i_1}{i_2}$?

Two straight infinitely long current-carrying wires are kept along the $z-$axis at the coordinates $(0, a, 0)$ and $(0, -a, 0)$ respectively, as shown in the figure. The current in each wire is equal and directed along the negative $z-$axis (into the plane of the paper). The variation of the magnetic field on the $x-$axis will be approximately:

$A$ 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 $(\mu_0 = \text{permeability of free space})$: