The resultant magnetic moment of three magnetic dipoles, each of the magnetic moment \(M\) shown in the…

The resultant magnetic moment of three magnetic dipoles, each of the magnetic moment \(M\) shown in the arrangement is
  1. \(\sqrt{2} M\)
  2. \((\sqrt{2}+1) M\)
  3. \((\sqrt{2}-1) M\)
  4. \(M\)

Solution

Three magnetic moments of magnetic dipole, are shown in the figure below as,
Here, \(M_1=\sqrt{M_A^2+M_B^2+2 M_A M_B \cos 90^{\circ}}\) \(\begin{aligned} & \Rightarrow \quad M_1=\sqrt{M^2+M^2+0} \\ & \Rightarrow \quad M_1=M \sqrt{2} \end{aligned}\) Now, the resultant, magnetic moment, \(\begin{aligned} & M_{\text {resultant }}=M_1+M_C \\ & \left(\because M_1 \text { and } M_C\right. \text { are } \\ \Rightarrow \quad & M_{\text {resultant }}=M \sqrt{2}+M \\ \Rightarrow \quad & M_{\text {resultant }}=(1+\sqrt{2}) \mathrm{M} \end{aligned}\) \((\because M_1 \text { and } M_C \text { are in the same direction) }\) \(\therefore\) correct option is (b).

Asked in: AP EAMCET 2019 (23 Apr Shift 1)

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