Question

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

• A. $\frac{1}{cosx}$
• B. $\frac{1}{sinx}$
• C. $\frac{1}{tanx}$
• D. $cosx$

Answer 1

The correct option is A $\frac{1}{cosx}$

In first case $tan\theta =\frac{B_V}{B_H}$ ..... (i)
Second case $tan\theta =\frac{B_V}{B_{H}cosx}$ ..... (ii)
From equation (i) and (ii), $\frac{tan{\theta }^{\prime }}{tan\theta }=\frac{1}{cosx}$