Q2 of 44 Page 200

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?

The earth’s core contains iron in molten state which is not ferromagnetic in nature hence geologists do not regard this as a source of earth’s magnetism.


Fact: After Curie temperature (Tc) materials lose permanent magnetism. This is due to inability is magnetic domains to align properly. After this temperature magnetic materials attain paramagnetic nature.


More from this chapter

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1

Answer the following question regarding earth’s magnetism:

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?

 2

Answer the following question:

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?

 2

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?

 2

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?