Answer :
Answer:
Option (C)
Explanation:
A metal detector is usually defined as an instrument that is commonly used to detect the presence of metals in the bags and luggage. It is very widely used in places like airports, railway stations, and other important official places.
This device is generally activated with the help of electromagnetic induction. It contains a single or numerous inducting coils which are connected to the elements placed on the ground surface. These used materials are metallic in nature. Within the region of the electromagnetic field, when any metallic substance enters, it immediately gains energy and thereby transmits an electromagnetic field of its own.
Thus, the correct answer is option (C).