In an atom, electrons revolve around the nucleus along a path of radius $0.72 \text{ Å}$, making $9.4 \times 10^{18}$ revolutions per second. The equivalent current is [given, $e = 1.6 \times 10^{-19} \text{ C}$]. (in $\text{A}$)

Which of the following gives the value of the magnetic field according to Biot-Savart's law?

Two long current-carrying conductors are placed parallel to each other at a distance of $8 \, cm$ between them. The magnitude of the magnetic field produced at the mid-point between the two conductors due to the current flowing in them is $300 \, \mu T$. The equal current flowing in the two conductors is ...............

$A$ current of $1\,A$ is passed through a hexagonal conducting wire of side $1\,m$. The magnetic induction at its centre $O$ in $Wb/m^2$ will be

$A$ long straight wire,carrying current $I$,is bent at its mid-point to form an angle of $45^{\circ}$. The magnetic field induction (in tesla) at point $P$,at a distance $R$ from the point of bending,is equal to:

The magnitude of the magnetic field (in $SI$ units) at the centre of a hexagonal coil of side $10 \, cm$, having $50$ turns and carrying a current $I$ (Ampere), in units of $\frac{\mu_{0} I}{\pi}$ is: (in $\sqrt{3}$)