Wheatstone's Bridge - Practice Questions & MCQ

Wheatstone's Bridge

It is an arrangement of four resistances which can be used to measure one of them in terms of rest. Let R is an adjustable resistance, Pand Q are known resistance and S is an unknown resistance. To obtain valur of S we will close the keys K1 and K2 and will adjust R to obtain null deflection in the galvanometer. Then the balancing condition of bridge is 

$
\begin{aligned}
& \frac{P}{Q}=\frac{R}{S} \\
& V_B=V_D
\end{aligned}
$

(Balanced condition)
No current will flow through the galvanometer
unbalanced condition: $V_B>V_D$

$
\left(V_A-V_B\right)<\left(V_A-V_D\right)
$

Current will flow from $A$ to $B$