What does the ammeter $A$ read in the circuit shown in Fig.? What if the positions of the cell and the ammeter are interchanged?

 

In the circuit shown in Fig, determine the current in the resistance $CD$ and equivalent resistance between the points $A$ and $B$. The internal resistance of cell is negligible.

In Fig, $ABCDA$ is a uniform circular wire of resistance $2 \mathrm{\Omega }$. $AOC$ and $BOD$ are two wires along two perpendicular diameters of the circle, each having same resistance $1 \mathrm{\Omega }$. A battery of emf $\xi$ and internal resistance r is connected between the points $A$ and $D$. Calculate the equivalent resistance of the network.

In the circuit shown in Fig, find the currents $I$, $I_1$, $I_2$ and $I_3$. Given that emf of the battery
$=2 \mathrm{V}$, internal resistance of the battery $=2 \mathrm{\Omega }$ and resistance of the galvanometer $=4 \mathrm{\Omega }$.

Determine the current flowing through the galvanometer $G$ of the Wheatstone bridge shown in Fig.