why is there zero current when a light bulb burns out?
With the filamnt burned out there is no connection and no connection means no power is going through the wires; thus, no current.
Because the filament is burned out, so their is nothing left off the light bulb.
When a light bulb burns out, it means that the filament inside the bulb has broken or become disconnected, which results in an open circuit. An open circuit prevents the flow of electric current. In a functioning light bulb, the filament is made of a thin wire that provides resistance to the flow of electrons. As a result of this resistance, the filament heats up and emits light.
However, when the filament breaks or becomes disconnected, there is no longer a complete path for electrons to flow through, and the circuit is disrupted. Without a complete path, there is no longer a connection between the two ends of the filament. Since current is the flow of electrons through a closed circuit, when the circuit is broken, no current can flow. Therefore, when a light bulb burns out, there is zero current because there is no longer a continuous path for the electrons to travel along.