The value of current through the $20\,\Omega$ resistor is .................. $A$.

The equivalent resistance between $P$ and $Q$ in the given figure is ............... $\Omega$.

In a typical Wheatstone network,the resistances in cyclic order are $A = 10 \,\Omega $,$B = 5 \,\Omega $,$C = 4 \,\Omega $ and $D = 4 \,\Omega $. What should be done for the bridge to be balanced?

When the value of $R$ in the balanced Wheatstone bridge, shown in the figure, is increased from $5 \Omega$ to $7 \Omega$, the value of $S$ has to be increased by $3 \Omega$ in order to maintain the balance. What is the initial value of $S$ (in $\Omega$)?

In the following network,the current flowing through the $15\Omega$ resistance is: (in $A$)

The given Wheatstone bridge shows no deflection in the galvanometer joined between the points $B$ and $D$ (see figure). Calculate the value of $R$ in $\Omega$.