A string of lights in a series circuit is not working. Which of the following is most likely the cause? A light bulb burned out and “opened” the circuit.
A light bulb burned out and “closed” the circuit.
One of the light bulbs is dimmer than the others.
One of the light bulbs is brighter than the others.

A. A light burned out and "opened" the circuit

Explanation:

In a parallel circuit if a light bulb goes out the rest are fine because they each have independent routes to the battery. But in a series circuit when a light bulb goes out the rest goes out because the current is going in one pathway. To tell the difference of if it closed or opened the circuit, you have to know what they mean. Closing a circuit means a complete electrical connection, the  light bulbs will light and electricity will flow. Opening a circuit means the opposite. If the all the light bulbs have stopped working then the circuit is not complete, therefore it's open.

A. A light burned out and "opened" the circuit

Explanation:

In a parallel circuit if a light bulb goes out the rest are fine because they each have independent routes to the battery. But in a series circuit when a light bulb goes out the rest goes out because the current is going in one pathway. To tell the difference of if it closed or opened the circuit, you have to know what they mean. Closing a circuit means a complete electrical connection, the  light bulbs will light and electricity will flow. Opening a circuit means the opposite. If the all the light bulbs have stopped working then the circuit is not complete, therefore it's open.

Explanation: