What is "immediately after the switch is closed?

As an AI language model, I cannot assume the context of the switch. However, generally speaking, "immediately after the switch is closed" means the moment the physical switch or digital one is turned on, activating an electrical circuit to connect to an electronic device, which will start running or will be waiting for a command. It can be an immediate action that sets off a chain of events, or it can simply switch on a light bulb or a fan instantly. The time frame for the switch's response depends on the device or system that it controls. For example, as soon as the light switch is turned on, the light bulb illuminates immediately, giving light in the room.