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 vertical plane and then it shows an angle of dip ${\theta }^{\prime }$ .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

Answer: (A)

In magnetic meridian, angle of dip is given by
$\tan \theta =\frac{V}{H}$ ...(i)
When dip circle is rotated in vertical plane, then
$\tan {\theta }^{\prime }=\frac{V}{H\cos x}$
$\therefore$ $\frac{\tan {\theta }^{\prime }}{\tan \theta }=\frac{1}{\cos x}$