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

Two long straight parallel wires carry currents of $8 \ A$ and $10 \ A$ in opposite directions. If the distance of separation between the wires is $9 \ cm$, then the net magnetic field at a point between the two wires, which is at a perpendicular distance of $4 \ cm$ from the wire carrying $8 \ A$ current is:

$AB$ and $CD$ are long straight conductors,separated by a distance $d$,each carrying a current $I$. The magnetic field at the midpoint of $BC$ is

$A$ wire $A$, bent in the shape of an arc of a circle, carrying a current of $2 \, A$ and having radius $2 \, cm$, and another wire $B$, also bent in the shape of an arc of a circle, carrying a current of $3 \, A$ and having radius $4 \, cm$, are placed as shown in the figure. The ratio of the magnetic fields due to the wires $A$ and $B$ at the common centre $O$ is

$A$ thin wire of length $l$ is carrying a constant current $i$. The wire is bent to form a circular coil. If the radius of the coil,thus formed,is $R$ and the number of turns in it is $n$,then which of the following graphs represents the variation of magnetic field induction $B$ at the centre of the coil?

$A$ $10 \ A$ current is passing through a very long wire of radius $5 \ cm$. The magnetic field at a distance of $2 \ cm$ inside from its curved surface is . . . . . . $\times 10^{-5} \ T$.