Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit, another set of three bulbs of the same wattage are connected in parallel to the same source.
$(а)$. Will the bulb in the two circuits glow with the same brightness? Justify your answer.
$(b)$. Now let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason.

$(a)$.  No, the bulbs in the two circuits will not glow with the same brightness. The resistance in the parallel connection of resistors is always less than the resistance in the series connections. So, the bulbs in parallel connection will grow with more brightness.

$(b)$. If one bulb gets fused, the entire circuit will break in a series connection. So, no current will flow into the bulbs. All three bulbs will stop glowing in a series connection. In a parallel connection, the situation is different. Even if the bulb gets fused, the current will continue to flow into the other two bulbs. So, in parallel connection, the other two bulbs will continue to glow.

Simply Easy Learning