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 $\theta \text{'}.$ Then $\frac{\tan \theta \text{'}}{\tan \theta }$ 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 $\frac{1}{\cos x}$

In first case $\tan \theta =\frac{B_V}{B_H}$
Second case $\tan \theta \text{'}=\frac{B_v}{B_H\cos x}$
From first case and second case,
$\frac{\tan \theta \text{'}}{\tan \theta }=\frac{1}{\cos x}$