Answer the following questions regarding earth's magnetism.
(a) A vector needs three quantities for its specification. name the three independent quantities conventionally used to specify the earth's magnetic field.
(b) The angle of dip at a location in southern india is about `18^@`. Would you expect a greater or lesser dip angle in Britain?
(c) If you made a map of magnetic field lines at Melbourne in Australia, would the lines seem to go into the ground or come out of the ground?
(d) Which direction would a compass needle point to, if located right on the geomagnetic north or south pole?
(e) The earth's field, it is claimed, roughly approximates the field due to a dipole of magnetic moment `8xx10^(22)JT^-1` located at its centre. Check the order of magnetude of this number in some way.
(f) Geologists claim that besides the main magnetic n-s poles, there are several local poles on the earth's surface oriented in different directions. How is such a thing possible at all?

Explanation

The earth.s magnetic field is only an approximation to consider it as a single dipole field. Local north-south poles may arise due to the presence of magnetised mineral deposits present inside the earth.