A) \[\pi ve{{r}^{2}}\]
B) \[\frac{\pi v{{r}^{2}}}{e}\]
C) \[\frac{\pi v\,e}{r}\]
D) \[\frac{\pi v{{r}^{2}}}{v}\]
Correct Answer: A
Solution :
Magnetic moment or magnetic dipole moment is a measure of the strength of a magnetic source. It is given by \[\mu =IA\] ? (i) where \[I\]is current and\[A\]the area. The effective current\[(I)\]is\[I=\frac{e}{T}\] where\[e\]is electron charge and\[T\]the time period. Also,\[v=\frac{1}{T}=\]frequency and area \[A=\pi {{r}^{2}}\], where\[r\]is radius of circular path. Putting these values in Eq. (i), we get \[\mu =ev.\pi {{r}^{2}}\] Note: Magnetic moment can also expressed terms of angular momentum\[(L)\] \[\mu =IA=-\frac{2}{2{{M}_{e}}}L\]. where\[{{M}_{e}}\] is mass of electron.You need to login to perform this action.
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