At a given place on the Earth,the angle between the Magnetic Meridian and the Geographic Meridian is called . . . . . . .

At a certain place,the angle of dip is $30^{\circ}$ and the horizontal component of the Earth's magnetic field is $0.5 \ G$. The Earth's total magnetic field (in $G$) at that place is:

Consider the plane $S$ formed by the dipole axis and the axis of the Earth. Let $P$ be a point on the magnetic equator and in plane $S$. Let $Q$ be a point of intersection of the geographical and magnetic equators. Obtain the declination and dip angles at $P$ and $Q$.

The angle of dip at a place is $60^{\circ}$. At this place,the total intensity of the Earth's magnetic field is $0.64 \text{ units}$. The horizontal intensity of the Earth's magnetic field at this place is . . . . . . $\text{units}$.

The lines of force due to the Earth's horizontal component of the magnetic field are:

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....$^o$