What are the two methods that are readily utilized in magnetometers to detect metal?

Magnetometers, used in security screening for detecting metallic objects, typically operate using two main methods:

Continuous-wave: Emits a constant electromagnetic field to detect disruptions caused by metal.

Pulsed-field: Emits bursts of energy and analyzes the return signals to identify metal objects.

These methods allow both walk-through and handheld devices to detect ferrous and non-ferrous metals.

A, C, and D include terms not applicable to standard magnetometer operation.