Cambridge Secondary (7-9). Stage 9. MCE Science. Workbook - Unit 12: Electrical Circuits - Question 8

Use two 1.5 V electric cells in holders, two LED lamps or 3 V lamps, electrical wires and two switches (a breadboard is optional). The cells are in series; each lamp has its own switch in a separate parallel branch, as shown.

Consider how switching one parallel lamp affects the brightness of the other. Why might this feature be useful in household circuits?