In the circuit shown,$P \ne R$. The reading of the galvanometer is the same with switch $S$ open or closed. Then:

What is the equivalent resistance between $A$ and $D$ in the given circuit? (All resistors are $10 \,\Omega$)

The readings of ammeters $A_1, A_2$ and $A_3$ will be respectively:

Twelve equal resistors,each of resistance $R$,are connected to form a skeleton cube. The equivalent resistance between two diagonally opposite corners is:

In a Wheatstone's bridge,three resistances $P, Q$ and $R$ are 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

The potential difference $(V_A - V_B)$ between the points $A$ and $B$ in the given figure is (in $V$)