Question

Wheatstone Bridge, Anybody?

Answer 1

please post your complete question.

Answer 2

yup @Shadowys U r right

Answer 3

Current through the middle branch i.e. the branch containing X will be 0 if:
\[\frac{ P }{ Q } = \frac{ R }{ S }\]
In this condition the bridge is said to be balanced. There will be no deflection in the galvanometer. So we can remove the middle branch and then simplify the circuit to answer the question.