question_answer

In a Wheatstone?s bridge, three resistance P, Q and R connected in the three arms and the fourth arm is formed by two resistances \[{{S}_{1}}\] and \[{{S}_{2}}\]connected in parallel. The condition for the bridge to be balanced will be

A) \[\frac{P}{Q}=\frac{2R}{{{S}_{1}}+{{S}_{2}}}\]

B) \[\frac{P}{Q}=\frac{R\left( {{S}_{1}}+{{S}_{2}} \right)}{{{S}_{1}}{{S}_{2}}}\]

C) \[\frac{P}{Q}=\frac{R\left( {{S}_{1}}+{{S}_{2}} \right)}{2{{S}_{1}}{{S}_{2}}}\]

D) \[\frac{P}{Q}=\frac{R}{{{S}_{1}}+{{S}_{2}}}\]