The number of turns of two circular coils $A$ and $B$ are $300$ and $200$ respectively. The magnetic moments of the two coils $A$ and $B$ are in the ratio $1:2$. If the two coils carry equal currents,then the ratio of radii of coils $A$ and $B$ is

$A$ circular coil of diameter $7\,cm$ has $24$ turns of wire carrying a current of $0.75\,A$. The magnetic moment of the coil is

$A$ charge $q$ is spread uniformly over an insulated loop of radius $r$. If it is rotated with an angular velocity $\omega$ with respect to the normal axis,then the magnetic moment of the loop is:

$A$ thin disc of radius $R$ and mass $M$ has charge $q$ uniformly distributed on it. It rotates with angular velocity $\omega$. The ratio of magnetic moment and angular momentum for the disc is

$A$ conducting ring of radius $R$ and one turn is formed from a conducting wire of length $L$ and on passing current $I$ the obtained magnetic dipole moment is $m$. If this wire is then converted to a ring of two turns and on passing electric current $I$,the new magnetic dipole moment obtained is . . . . . . .

$A$ current $i$ flows in a horizontal square loop of side $L$. Now,half of the loop is folded to be vertical. If $\overrightarrow {{\mu _1}}$ and $\overrightarrow {{\mu _2}}$ are the magnetic moments before and after folding,respectively,then: