What is the long wire that connect the mouse to the computer?

The long wire that connects a mouse to a computer is typically referred to as a "mouse cable" or simply a "mouse wire." This cable serves to transmit data (movements and clicks) from the mouse to the computer, as well as to supply power to the mouse if it is not wireless. It is usually a USB cable, though older mice may use other types of connectors like PS/2.

Modern mice usually have a USB Type-A connector on one end (which plugs into the computer) and a connector that fits into the mouse itself (often micro-USB, USB-C, or proprietary depending on the mouse model).

The length of the mouse cable can vary depending on the manufacturer and the intended use, with lengths ranging from a few feet to several meters.