Answer the following questions:
$(a)$ 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?
$(b)$ The earth's core is known to contain iron. Yet geologists do not regard this as a source of the earth's magnetism. Why?
$(c)$ 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?
$(d)$ 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?
$(e)$ 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?
$(f)$ Interstellar space has an extremely weak magnetic field of the order of $10^{-12}\; T$. Can such a weak field be of any significant consequence? Explain.
$(a)$ 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?
$(b)$ The earth's core is known to contain iron. Yet geologists do not regard this as a source of the earth's magnetism. Why?
$(c)$ 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?
$(d)$ 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?
$(e)$ 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?
$(f)$ Interstellar space has an extremely weak magnetic field of the order of $10^{-12}\; T$. Can such a weak field be of any significant consequence? Explain.
(N/A) Yes,the earth's magnetic field changes with time. It changes appreciably over a time scale of a few hundred years.
$(b)$ The earth's core contains molten iron. At the high temperatures present in the core,iron is not ferromagnetic,and therefore,it cannot be the source of the earth's magnetism.
$(c)$ The 'battery' or source of energy that sustains these currents is believed to be the radioactivity in the earth's interior.
$(d)$ Geologists can infer the history of the earth's magnetic field by analyzing the magnetization of rocks formed during their solidification in the distant past.
$(e)$ At large distances (greater than about $30,000\; km$),the earth's magnetic field is distorted by the solar wind and the interaction with the ionosphere,where the motion of charged particles creates additional magnetic fields.
$(f)$ Yes,even a weak magnetic field of $10^{-12}\; T$ can have significant consequences over the vast distances of interstellar space,as it can cause the deflection of charged particles moving through it.
$(b)$ The earth's core contains molten iron. At the high temperatures present in the core,iron is not ferromagnetic,and therefore,it cannot be the source of the earth's magnetism.
$(c)$ The 'battery' or source of energy that sustains these currents is believed to be the radioactivity in the earth's interior.
$(d)$ Geologists can infer the history of the earth's magnetic field by analyzing the magnetization of rocks formed during their solidification in the distant past.
$(e)$ At large distances (greater than about $30,000\; km$),the earth's magnetic field is distorted by the solar wind and the interaction with the ionosphere,where the motion of charged particles creates additional magnetic fields.
$(f)$ Yes,even a weak magnetic field of $10^{-12}\; T$ can have significant consequences over the vast distances of interstellar space,as it can cause the deflection of charged particles moving through it.
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