Question

How do the lights in a series circuit behave when one bulb burns out?

The rest of the bulbs continue to shine at maximum brightness.
The rest of the bulbs continue to shine at a lower brightness.
The rest of the bulbs continue to shine at a higher brightness.
The rest of the bulbs stop shining and shut off.

Answer 1

The rest of the bulbs stop shining and shut off.

In a series circuit the same current flows through every bulb; if one bulb burns out (its filament breaks) it opens the circuit, stopping the current and extinguishing all the bulbs.