What solenoid component physically moves a mechanically operated device?

The plunger is the correct component as it serves as the physical mechanism that moves when a solenoid is activated. In a solenoid, when an electric current flows through the coil, it generates a magnetic field. This magnetic field attracts the plunger, causing it to move linearly. This movement is what translates the electrical energy into mechanical motion, enabling the solenoid to operate devices such as valves or locks.

The other components have distinct roles: the valve regulates fluid flow, the coil generates the magnetic field when energized, and the spring often serves to return the plunger to its initial position once the electric current is removed. However, it is the plunger that is the key element responsible for the physical movement required to manipulate the mechanically operated device.