Earthʹs magnetic field
A)is principally generated in the inner core.
B)is constant in its intensity.
C)is variable,and it has faded to zero and returned to full strength with the polarity reversed.
D)remains a mystery as to its cause.

Question

Quizplus · Accepted Answer

Earth's magnetic field is variable and has flipped its polarity many times in the past. This phenomenon has been recorded in rocks and provides evidence for the movement of tectonic plates over time. The cause of Earth's magnetic field is understood to be generated by the movement of molten iron in the outer core, which creates electric currents that produce the magnetic field.

Earthʹs Magnetic Field