ASVAB (Armed Services Vocational Aptitude Battery)Paragraph Comprehension (PC)Easy
Read the following passage: "The Earth's magnetic field, also known as the geomagnetic field, extends from the Earth’s interior out into space, protecting our planet from solar wind and cosmic rays. This field is generated by electric currents due to the motion of convection currents of molten iron in the Earth's outer core. Without this protective field, charged particles from the sun would strip away the Earth's atmosphere, making life on the surface impossible. The magnetic field also causes the phenomenon of the aurora, visible near the poles, as charged particles interact with atmospheric gases. Furthermore, it aids in navigation for many animals, including birds and sea turtles, and is utilized by human compasses." According to the passage, what is the primary source of the Earth's magnetic field?
- AMagnetic rocks in the Earth's crust
- BInteraction of solar wind with the atmosphere
- CMolten iron convection in the outer core
- DStatic charges on the Earth's surface
Show answer & explanationAnswer & explanation
Correct answer: C. Molten iron convection in the outer core
The passage explicitly states, 'This field is generated by electric currents due to the motion of convection currents of molten iron in the Earth's outer core,' directly identifying the source.
Why the other options are wrong
- A. Magnetic rocks are not mentioned as the primary source of the global field.
- B. Solar wind interaction is a consequence, not the source, of the magnetic field.
- D. The passage does not mention static charges as the source.
Geomagnetic Field Source
The Earth's magnetic field originates from the dynamic motion of molten iron within the planet's outer core.
- Known as the Geodynamo theory.
- Convection currents create electric currents.
- Essential for protecting Earth from solar radiation.
Memory trick: Molten core's movement Makes Magnetic Might.