Earth's Magnetic Field

question 18

Multiple Choice

Earth's magnetic field

• A)is variable,and it has phased to zero some nine times during the past 4 million years.
• B)is constant in its intensity.
• C)remains a mystery as to its cause.
• D)is principally generated in the inner core.
• E)has repelled iron from the core to the surface.

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Definitions:

Manual Motor Starter

A manually operated switch designed to start and stop motors while providing overload protection.

Energize

To supply electricity to a circuit or device, making it operational or "live."

Motor Load

The amount of power a motor needs to perform its task, reflecting the mechanical demand placed on it.

Automatic Restart

A feature in machinery that allows it to automatically resume operation after an interruption or stop.