A dip circle lies initially in the magnetic meridian, it shows an angle of dip $\delta$ at a place. The dip circle is rotated through an angle $\alpha$ in the horizontal plane and then it shows an angle of dip $\delta^{\prime}$. Hence $\frac{\tan \delta^{\prime}}{\tan \delta}$ is
$\cos \alpha$
$1 / \sin \alpha$
$1 / \tan \alpha$
$1 / \cos \alpha$
The direction of the null points is on the equatorial line of a bar magnet, when the north pole of the magnet is pointing
What is the angle between axis of rotation and magnetic axis of earth ?
At a certain place, the horizontal component of earth's magnetic field is $\sqrt 3 $times the vertical component. The angle of dip at that place is....$^o$
At a point $A$ on the earth's surface the angle of $\operatorname{dip}, \delta=+25^{\circ} .$ At a point $B$ on the earth's surface the angle of dip, $\delta=-25^{\circ} .$ We can interpret that
Lines which represent places of constant angle of dip are called