Here's why:

* Closed circuit: A closed circuit allows electricity to flow continuously from the power source, through the light bulb, and back to the source. This is what makes the light bulb turn on.

* Open circuit: An open circuit breaks the flow of electricity. This can happen due to a variety of reasons, such as:

* A broken wire

* A loose connection

* A faulty switch

* A blown fuse or tripped circuit breaker

When the circuit is open, electricity cannot reach the light bulb, and it remains off.