What is the value of the current flowing through the galvanometer in the balanced condition of a Wheatstone bridge?

In the circuit,$E_1 = E_2 = E_3 = 2 \text{ V}$ and $R_1 = R_2 = 4 \text{ } \Omega$. Then the current flowing through $E_2$ is

In the circuit shown below,the ammeter reading is zero. Then the value of the resistance $R$ is (in $\Omega$)

The value of current $I$ in the given current distribution is: (in $A$)

The internal resistances of two cells shown are $0.1\,\Omega$ and $0.3\,\Omega$. If $R = 0.2\,\Omega$,the potential difference across the cell

In the adjoining circuit,the galvanometer $G$ shows zero deflection. If the batteries $A$ and $B$ have negligible internal resistance,the value of the resistor $R$ will be .............. $\Omega$.