$A$ current of $1 \, A$ flows through an infinitely long straight wire. The magnetic field produced at a point $1 \, m$ away from it is:

$A$ single current-carrying loop of wire with current $I$ flowing in an anticlockwise direction when seen from the $+ve\;z$ direction,lying in the $xy$ plane,is shown in the figure. The plot of the $\hat{j}$ component of the magnetic field $(B_y)$ at a distance $a$ (less than the radius of the coil) on the $yz$ plane versus the $z$ coordinate looks like:

The dimensions of the ratio of magnetic flux $(\phi)$ and permeability $(\mu)$ are

$A$ straight wire of diameter $0.5\, mm$ carrying a current of $1\, A$ is replaced by another wire of $1\, mm$ diameter carrying the same current. The strength of the magnetic field at a point far away is

$A$ long insulated copper wire is closely wound as a spiral of $N$ turns. The spiral has inner radius $a$ and outer radius $b$. The spiral lies in the $X-Y$ plane and a steady current $I$ flows through the wire. The $Z$-component of the magnetic field at the center of the spiral is

An infinitely long straight conductor is bent into the shape as shown in the figure. It carries a current $I$ ampere and the radius of the circular loop is $r$ metre. Then the magnetic induction $B$ at the centre $C$ of the circular part is: