Question

In a hydrogen atom, an electron of mass $m$ and charge e revolves in an orbit of radius $r$ making $n$ revolutions per second. If the mass of hydrogen nucleus is $M$, the magnetic moment associated with the orbital motion of electron is

• A. $\frac{\pi n e r^{2} m}{M+m}$
• B. $\pi n e r^{2}$
• C. $\frac{\pi n e r^{2}}{m}$
• D. $\frac{\pi n e r^{2} m}{M}$

Answer 1

Answer: (B)

Magnetic moment $= NiA$
$i=\frac{q}{T}=e n $
$A=\pi r^{2} $
and $N=1 $
$\Rightarrow $ Magnetic moment
$(m)=(1)(e n)\left(\pi r^{2}\right)$