MCQ
When two magnetic moments are compared using equal distance method the deflections produced are $45^o$ and $30^o$. If the length of magnets are in the ratio  $1 : 2,$  the ratio of their pole strengths is
  • A
    $3:1$
  • B
    $3:2$
  • C
    $\sqrt 3 :1$
  • $2\sqrt 3 :1$

Answer

Correct option: D.
$2\sqrt 3 :1$
d
(d)$\frac{{{M_1}}}{{{M_2}}} = \frac{{\tan {\theta _1}}}{{\tan {\theta _2}}} \Rightarrow \frac{{{m_1}{L_1}}}{{{m_2}{L_2}}} = \frac{{\tan {\theta _1}}}{{\tan {\theta _2}}}$
$ \Rightarrow \frac{{{m_1}}}{{{m_2}}} = \frac{2}{1} \times \frac{{\tan 45^\circ }}{{\tan 30^\circ }} = \frac{{2\sqrt 3 }}{1}$

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