If you want to stop the current flow through device 3 in the circuit shown above, which one of the following single switches should you open?

a. switch s2
b. switch s4
c. switch s3
d. switch s5- right
hope this hell someone out . the answer is d

Assuming G stands for generator or power source, then anything that cuts the main current will stop everything (including device 3) from functioning.

You will notice that this can be accomplished by opening either switch 1 or switch 5.

We need to stop everything because device 3 is parallel connected.

Yes, choice D (switch 5 is correct, out of the given choices).

Igotchu on that if you still need it