Question

A dip needle on a plane perpendicular to magnetic meridians will remain

• A. horizontal
• B. vertical
• C. inclined at ${45}^0$ with horizontal
• D. in any direction

Answer 1

The correct option is B vertical

On a plane perpendicular to the magnetic meridian the horizontal component of magnetic field will become zero.
$B_H^{\prime }=B_H\cos 90$
$B_H^{\prime }=0$
therefore, angle of dip becomes $\tan \varphi =B_v/B_H^{\prime }$
therefore, $\varphi =90$
Therefore, dip needle will become perpendicular.