Answer the following questions:The charged currents in the outer conducting regions of the earth’s core are thought to be responsible for earth’s magnetism. What might be the ‘battery’ (i.e., the source of energy) to sustain these currents?

Answer the following questions:The earth’s core Is known to contain Iron. Yet geologists do not regard this as a source of the earth’s magnetism. Why?

Answer the following questions: The earth’s magnetic field varies from point to point in space. Does it also change with time? If so, on what time scale does it change appreciably?

Answer the following: The discharging current in the atmosphere due to the small conductivity of air is known to be 1800 A on an average over the globe. Why then does the atmosphere not discharge itself completely in due course and become electrically neutral? In other words, what keeps the atmosphere charged?

Answer the following questions:The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?

Answer the following questions:The earth may have even reversed the direction of Its field several times during its history of 4 to 5 billion years. How can geologists know about the earth’s field in such distant past?

Answer the following questions regarding earth’s magnetism: In which direction would a compass free point to, If located right on the geographic north or south pole?

Answer the following questions regarding earth’s magnetism:The earth’s field, It Is claimed, roughly approximates the field due to a dipole of magnetic moment 8 xx 10^22 J "T1 located at Its centre. Check the order of magnitude of this number In some way.

Answer the following questions regarding earth’s magnetism:A vector needs three quantities for Its specification. Name the three Independent quantities conventionally used to specify the earth’s magnetic field.

Answer the following questions regarding earth’s magnetism:The angle of dip at a location In southern India Is about 18^@ . Would you expect a greater or smaller dip angle In Britain?

Answer the following questions regarding earth’s magnetism: f 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?