The current associated with an electron of charge $e$ moving in a circular orbit of radius $r$ with speed $v$ around the positively charged nucleus is given by

$A$ current-carrying small loop behaves like a small magnet. If $A$ is its area and $M$ is its magnetic moment,the current in the loop will be

$A$ steady current $i$ flows in a small square loop of wire of side $L$ in a horizontal plane. The loop is now folded about its middle such that half of it lies in a vertical plane. Let $\overrightarrow {{\mu _1}} $ and $\overrightarrow {{\mu _2}} $ respectively denote the magnetic moments due to the current loop before and after folding. Then

The radius of a circular loop is $r$ and a current $i$ is flowing in it. The equivalent magnetic moment will be

$A$ circular coil of radius $4\, cm$ and of $20$ turns carries a current of $3$ amperes. It is placed in a magnetic field of intensity $0.5\, Wb/m^2$. The magnetic dipole moment of the coil is.......$A \cdot m^2$.

$A$ wire carrying current $I$ is bent in the shape $A, B, C, D, E, F, A$ as shown,where rectangle $A, B, C, D, A$ and $A, D, E, F, A$ are perpendicular to each other. If the sides of the rectangles are of lengths $a$ and $b$,then the magnitude and direction of the magnetic moment of the loop $A, B, C, D, E, F, A$ is