Question

Explain how electromagnetic induction can be used to detect metals? This technique is particularly important in detecting buried landmines for disposal, geophysical prospecting, and at airports.

a) Metals absorb electromagnetic waves, producing detectable signals.

b) Metals generate their own electromagnetic fields, allowing for detection.

c) Metals disrupt magnetic fields, inducing currents in nearby coils for detection.

d) Electromagnetic induction cannot be used to detect metals.

Answer 1

Electromagnetic induction detects metals through the creation of eddy currents that alter the properties of nearby coils, enabling their detection by metal detectors.

Step-by-step explanation:

Electromagnetic induction can be used to detect metals through the disruption of magnetic fields. When a metal is introduced to an alternating magnetic field, it distorts this field, resulting in eddy currents in the metal. These currents create a secondary magnetic field that can induce a current in nearby coils.

This induction process can lead to a detectable change in the coil's properties, such as its self-inductance or resonate frequency. Metal detectors work by sending an electromagnetic wave from a transmitter coil and analyzing the signal in a receiver coil; any induced electrical current in the metal causes a change in the signal, which the detector circuitry can identify.

This technique is fundamental at airports, in geophysical prospecting, and crucial for the detection and disposal of buried landmines.