The magnetic field at the center of a current-carrying circular loop is $B_{1}$. The magnetic field at a distance of $\sqrt{3}R$ from the center on its axis is $B_{2}$,where $R$ is the radius of the loop. The value of $B_{1} / B_{2}$ 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:

What is the convention for an electric or magnetic field emerging out of the plane of the paper and going into the plane of the paper?

$A$ long straight wire carrying a current of $30\,A$ is placed in an external uniform magnetic field of induction $4 \times 10^{-4}\,T$. The magnetic field is acting parallel to the direction of the current. The magnitude of the resultant magnetic induction in tesla at a point $2.0\,cm$ away from the wire is

According to the Biot-Savart law,what is the magnetic field at a point on the axis of a current-carrying wire?

$A$ square frame of side $1 \ m$ carrying a current $I$ produces a magnetic field $B$ at its centre. The same current is passed through a circular coil having the same perimeter as the square. The magnetic field at the centre of the circular coil is $B^{\prime}$. The ratio of $\frac{B}{B^{\prime}}$ is