Moving Charges And Magnetism Ques 7

7. A charged paritcle (charge $q$ ) is moving in a circle of radius $R$ with uniform speed $v$. The associated magnetic moment $\mu$ is given by

[2007]

(a) $q v R^{2}$

(b) $q v R^{2} / 2$

(c) $q v R$

(d) $q v R / 2$

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Answer:

Correct Answer: 7.(d)

Solution:

  1. (d) Magnetic moment, $m=I A$

$=\frac{q v}{2 \pi R}(\pi R^{2})=\frac{q v R}{2}$

$[\because I=\frac{q}{T}$ and $T=\frac{2 \pi R}{v}]$