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Our Planet is surrounded by a magnetic field.In our experience this phenomenon is revealed for example by a compass needle that points approximately to the north.According to modern geophysical ideas when, at a given point and at a certain time,a measurement of the earth's magnetic field in carried out, the measured value is the result of the superimposition of contributions can be, at a first glance, considered separately,each of them corresponding to a different source.
* The main field, generated in the earth's fluid core by a gerdynamo mechanism;
* The crustal field,generated by magnetized rocks in the earth's crust;
* The external field,produced by electric currents flowing in the ionosphere and in the magnetosphere owing to the interaction of the solar electromagnetic radiation and the solar wind with the earth's magnetic field;
*The magnetic field resulting from an electromagnetic induction process generated by electric current induced in the crust and the upper mantle by the external magnetic field time variations.
nic....:)
Shishirbharti94 20 hours ago
NICELY EXPLAINED!!!
TheIndianlover 2 weeks ago