Question

A dip needle lies initially in the magnetic meridian when it shows an angle of dip $\theta$ at a place. The dip circle is rotated through an angle $x$ in the horizontal plane and then it shows an angle of dip $\theta$'. Then $\frac{\tan {\theta }^{{}^{\prime }}}{\tan \theta }$ is

• A. $\frac{1}{\cos x}$
• B. $\frac{1}{\sin x}$
• C. $\frac{1}{\tan x}$
• D. $\cos x$

Answer 1

The correct option is A $\frac{1}{\cos x}$

$\tan \theta =\frac{B_V}{B_H};\tan {\theta }^{\prime }=\frac{B_V}{B_H\cos x};\frac{\tan {\theta }^{{}^{\prime }}}{\tan \theta }=\frac{1}{\cos x}$