How to complete this electrical current table?

I don't understand it. Could someone please explain it?enter image source here

1 Answer
Mar 22, 2018

a) all globes are on
b)all are off
c) G and I are on, rest off
d)G, I, J are on - H is off


For current to flow, there must be a complete closed path from one end of the battery to the other. To see whether a globe will be on just check whether you can draw a continuous line from the positive end of the battery, through the globe, on to the negative end (you are not allowed to draw a line through a switch that is open),

In d), current will flow through the closed key F, rather than the higher resistance path offered by the globe H. The globe H will be off in this case.