An electron revolves around a nucleus with rotational frequency $f$ in a circular orbit. Due to this,the magnetic induction produced at the nucleus position is $B$. The radius of the circular orbit is directly proportional to:

$A$ straight long wire is carrying current $I$. The ratio of magnetic field due to this wire at perpendicular distance $2 \text{ cm}$ and $5 \text{ cm}$ respectively from the wire is

Two infinitely long parallel wires carry currents of magnitude $I_1$ and $I_2$ and are at a distance $4 \, cm$ apart. The magnitude of the net magnetic field is found to reach a non-zero minimum value between the two wires at a distance of $1 \, cm$ from the first wire. The ratio of the two currents and their mutual direction is

Give the differences between Biot-Savart law and Coulomb's law.

Which one of the following options represents the magnetic field $\vec{B}$ at the origin $O$ due to the current $I$ flowing in the given wire segments lying on the $xy$ plane?

The ratio of the magnetic field at the centre of a current-carrying circular wire and the magnetic field at the centre of a square coil made from the same length of wire will be