Answer:
Both technicians are correct.
Step-by-step explanation:
A relay can be defined as an electromagnetic device (switch) that electrically controls the automatic opening and closing of the contacts of an electric circuit. Relays are used to control or regulate an electrical circuit through a power signal (quantity) such as voltage and current.
One of the components used in an electromagnetic switch (relay) is a solenoid. A solenoid is made up of a core that moves to open or close a circuit breaker or electronic switch, when it is energized.
In this scenario, Technician A says that a relay is an electromagnetic switch. Technician B says that a solenoid uses a movable core.
Hence, both Technician A and Technician B are correct.