$A$ wire of length $2\,m$ is bent into a circular loop. When a current of $1\,A$ is passed through the loop,then the magnetic moment of the loop is

The ratio of the magnetic field at the centre of a current-carrying circular coil to its magnetic moment is $\alpha$. If the current and radius both are doubled,then the new ratio will become:

The magnitude of the magnetic moment of the current loop shown in the figure is

An insulating thin rod of length $l$ has a linear charge density $\rho(x) = \rho_0 \frac{x}{l}$ on it. The rod is rotated about an axis passing through the origin $(x = 0)$ and perpendicular to the rod. If the rod makes $n$ rotations per second,then the time-averaged magnetic moment of the rod is:

The ratio of the magnetic field at the centre of a current-carrying circular loop to its magnetic moment is '$x$'. When both the current and the radius are tripled, the new ratio will be:

Magnetic field at the centre of a circular loop of area $A$ is $B$. The magnetic moment of the loop will be ($\mu_{0} =$ permeability of free space).