The magnetic field at the centre of a single-turn circular coil of a given length of wire carrying a current $I$ is $B$. If the same wire is bent into a circular coil of two turns and the same current $I$ is passed through it,the new magnetic field at the centre will be:

$A$ uniform conducting wire of length $24a$ and resistance $R$ is wound up as a current-carrying coil in the shape of an equilateral triangle of side $a$ and then in the form of a square of side $a$. The coil is connected to a voltage source $V_{0}$. The ratio of the magnetic moment of the coils in the case of the equilateral triangle to that of the square is $1 : \sqrt{y}$, where $y$ is ..... .

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

Two concentric circular loops of radii $r_{1} = 30 \, cm$ and $r_{2} = 50 \, cm$ are placed in the $X-Y$ plane as shown in the figure. $A$ current $I = 7 \, A$ flows through them in the directions shown. The net magnetic moment of this system of two circular loops is approximately:

The magnetic moments associated with two closely wound circular coils $A$ and $B$ of radius $r_A = 10 \ cm$ and $r_B = 20 \ cm$ respectively are equal. If $N_A, I_A$ and $N_B, I_B$ are the number of turns and current of $A$ and $B$ respectively,then which of the following relations is correct?

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