Answer to Question #269879 in Physics for Ella

Question

At airport, a person is made to walk through a doorway of a metal detector, for security reasons. If he is carrying anything made of metal, the metal detector emits a sound. On what principle does the metal detector work?

Answer 1

In short, pass-through metal detectors, or arched metal detectors, based on pulse induction technology. Pass-through metal detectors send powerful short pulses of current through the coil. Each pulse generates a magnetic field. When a metal object passes through a magnetic field, a reflected magnetic field is created. This magnetic field reacts with the receiver coil, which turns on the alarm system.