$A$ charge $q$ is spread uniformly over an isolated ring of radius $R$. The ring is rotated about its natural axis with an angular velocity $\omega$. Magnetic dipole moment of the ring is

In a hydrogen atom,the electron is making $6.6 \times 10^{15} \text{ rev } s^{-1}$ around the nucleus in an orbit of radius $0.528 \text{ Å}$. The magnetic moment in $\text{A-m}^2$ is:

$A$ particle of mass $m$ and charge $Q$ moving with a speed $v$ in a circular path of radius $R$ has a magnetic moment $\mu$. If the mass of the particle is doubled and it maintains the same speed while revolving in the same circular path, then the magnetic moment will be

$A$ $100$-turn closely wound circular coil of radius $5 \text{ cm}$ has a magnetic field of $3.14 \times 10^{-3} \text{ T}$ at its centre. The current flowing through the coil, and the magnitude of the magnetic moment of this coil are, respectively: (Take $\mu_0 = 4\pi \times 10^{-7} \text{ T m/A}$)

Magnetic induction at the centre of a circular loop of area $\pi \ m^2$ is $0.1 \ T$. The magnetic moment of the loop is ( $\mu_0 = \text{permeability of air}$ ).

$A$ circular loop and a square loop are formed from two wires of same length and cross-section. The same current is passed through them. The ratio of their dipole moments is