There are two different groups, A and B, of bulbs for the Christmas tree. Only incandescent bulbs are used, ie bulbs where a resistive w ire is overheated to emit light. For group A of bulbs, when one bulb is removed (or burned out), the rest remain illuminated. For group B, when one bulb is removed, the rest no longer work. This means that In A there are only a few bulbs in series and for this reason, when one is removed, the others always remain illuminated. In group B, all the bulbs are in parallel In group A, I took out one bulb in a set of two bulbs In group B, all bulbs are in series

There are two different groups, A and B, of bulbs for the Christmas tree. Only incandescent bulbs are used, ie bulbs where a resistive w ire is overheated to emit light. For group A of bulbs, when one bulb is removed (or burned out), the rest remain illuminated. For group B, when one bulb is removed, the rest no longer work. This means that In A there are only a few bulbs in series and for this reason, when one is removed, the others always remain illuminated. In group B, all the bulbs are in parallel In group A, I took out one bulb in a set of two bulbs In group B, all bulbs are in series