What is another name for a reed switch?

• A. A switch that detects sound.
• B. A push-button switch.
• C. The formal name of a magnetic switch—it's a simple switch that turns on and off with magnet.
• D. A mechanical switch actuated by pressure.

Answer: (C)

A reed switch is a magnetic switch: it closes or opens the circuit when a magnet is brought near. Inside a glass envelope, two ferromagnetic reeds come together in the presence of a magnetic field and separate when the field is removed. This simple magnetic actuation is exactly what defines a reed switch, which is why describing it as the formal name of a magnetic switch that turns on and off with a magnet fits best. The other options describe devices activated by sound, a push button, or pressure, none of which rely on magnetism, so they don’t match how a reed switch operates.