Chapter 22, Problem 1CQ

Volcanic and other such activity at the mid-Athletic ridge extrudes material to fill the gap between separating tectonic plates associated with continental drift. The magnetization of rocks is found to reverse in a coordinated manner with distance from the ridge. What does this imply about the Earth's magnetic field and how could the knowledge of the spreading rate he used to give its historical record?

To determine

What does this imply about the Earth's magnetic field?

Answer to Problem 1CQ

It implies that there is no magnetic force at the center of the earth where molten metal is present, and also suggest that there is a strong magnetic field outside the earth under the influence of which the earth gets magnetize.

Explanation of Solution

When the molten lava comes out form the volcano, it gets solidifies into a rock and it get magnetize in the direction of the local magnetic field, and at the center of the lava there is no magnetic field.

Similarly, it indicates that when the earth is in molten state there is no magnetic field, but as it starts cooling the outer layer of the earth gets magnetize under the influence of strong magnetic field. It also implies that there is a strong magnetic field outside the earth due to which the earth gets magnetize at the North and the South Pole.

Conclusion:

It implies that there is no magnetic force at the center of the earth where molten metal is present, and also suggest that there is a strong magnetic field outside the earth under the influence of which the earth gets magnetize.