(2) Hint: Magnetic equator crosses the geographical equator at two points.
The angle of dip is zero when the magnetic equator crosses the geographical equator. The geographic equator lying in magnetic north of the magnetic equator will have B_v vertically upwards thus, the angle of dip is negative. When the geographic equator lies in magnetic south of the magnetic equator B_v will be vertically downwards. Thus, the angle of dip is positive. The angle of dip is maximum and minimum when the values of B_v will be at points which are maximum north and maximum south of the magnetic equator. Hence, we can say that angle of the dip is bounded. Thus, we can say that angle of dip is zero at specific points, can be negative or positive and is bounded.