$A$ closely wound solenoid of $800$ turns and area of cross section $2.5 \times 10^{-4} \text{ m}^2$ carries a current of $3.0 \text{ A}$. The magnetic moment associated with it is . . . . . . . (in $\text{ JT}^{-1}$)

$A$ coil of $n$ turns and radius $R$ carries a current $I$. It is unwound and rewound again to make another coil of radius $\frac{R}{3}$,with the current remaining the same. The ratio of the magnetic moment of the new coil to that of the original coil is:

$A$ rod of length $l$ having uniformly distributed charge $Q$ is rotated about one end with constant frequency $f$. Its magnetic moment is:

$A$ current $i$ is flowing in a conductor of length $l$. When it is bent in the form of a circular loop,then its magnetic moment will be-

Write the equation of the magnetic dipole moment in terms of electric current.

$A$ small bar magnet experiences a torque of $0.016 \ Nm$ when placed with its axis at $30^{\circ}$ with an external magnetic field of $0.04 \ T$. If the bar magnet is replaced by a solenoid of cross-sectional area $1 \ cm^2$ and $1000$ turns, having the same magnetic moment as that of the bar magnet, then the current flowing through the solenoid is: (in $A$)