Question

The angle of dip in a given meridian, making an angle $30^{\circ }$ with the magnetic meridian is equal to $30^{\circ }$. The true angle of dip at the given point is :-

• A. ${\tan }^{-1}\left(\frac{1}{2}\right)$
• B. ${\tan }^{-1}(2)$
• C. ${\tan }^{-1}(\sqrt{2})$
• D. ${\tan }^{-1}\left(\frac{1}{\sqrt{2}}\right)$

Answer 1

Answer: (A)

$\tan {\theta }^{{}^{\prime }}=\frac{\tan \theta }{\cos \alpha }$
${\theta }^{{}^{\prime }}=\alpha =30^{\circ }$
$\therefore \tan \theta =(\tan 30)\left(\cos 30^{\circ }\right)=\frac{1}{\sqrt{3}}\times \frac{\sqrt{3}}{2}$