High School

Study the circuit below. When the switch is closed, all three light bulbs are lit. What will happen if bulb A burns out?

A. Bulbs B and C will stay lit.
B. All bulbs will go out.
C. Only bulb B will stay lit.
D. Only bulb C will stay lit.

Answer :

Final answer:

If bulb A burns out in a series circuit, it would break the circuit and cause all the other bulbs in the series, including bulbs B and C, to also go out.

Explanation:

If bulb A burns out in a circuit where light bulbs are connected in series, as is often the case with old strings of holiday lights, the electrical circuit would be broken. This would cause all the bulbs in the series to go out, not just the burnt bulb. This happens because in a series circuit, the current must flow through each component sequentially. If any part of the series is interrupted, the entire current flow stops, and thus all devices connected in series with the interruption, would go out. Since bulb A is part of the continuous path required for the current flow, its failure results in the cessation of current through the entire circuit, affecting bulbs B and C as well.

If bulb A burns out in a series circuit, the electrical current stops flowing which means all bulbs will go out, which corresponds to option (b).