Question

Linh builds a circuit from the diagram shown.

A rectangular box of lines with the long side vertical and an extra horizontal line about 2 thirds of the way up. The top line has a circle with an X in it labeled 1. The right side from top has a top circle 2 with an X in it then the connection with the extra line then a bottom circle 4 with an X in it. The extra line has a circle 3 with an X in it. The left side has a stack of horizontal lines near its bottom, which are, from top very short, short, very short, short.
If Linh removes bulb 3, which bulbs will remain lit?

1 only
1 and 2 only
4 only
1, 2, and 4

Answer 1

1, 2, and 4.

With bulb 3 removed the direct branch between the left node and the right mid node is open, but there is still a closed path from the battery through bulb 1 → bulb 2 → bulb 4 back to the battery, so those three bulbs remain lit.